:root {
            --proton: #ef4444;
            --neutron: #3b82f6;
            --electron: #eab308;
            --bg-dark: #020617;
            --glass-bg: rgba(255, 255, 255, 0.05);
            --glass-border: rgba(255, 255, 255, 0.1);
            --success: #22c55e;
            --error: #ef4444;
            --text-primary: #f1f5f9;
            --text-secondary: #94a3b8;
            --space-1: 8px;
            --space-2: 16px;
            --space-3: 24px;
            --space-4: 32px;
            --space-5: 40px;
            --space-6: 48px;
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
            background: var(--bg-dark);
            color: var(--text-primary);
            min-height: 100vh;
            overflow: hidden;
        }

        /* Glass Card Effect */
        .glass-card {
            background: var(--glass-bg);
            border: 1px solid var(--glass-border);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            border-radius: 1rem;
        }

        /* Top Bar */
        .top-bar {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            height: 60px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 0 var(--space-4);
            background: rgba(2, 6, 23, 0.95);
            border-bottom: 1px solid var(--glass-border);
            z-index: 100;
        }

        .nav-left {
            display: flex;
            align-items: center;
            gap: var(--space-2);
        }

        .nav-brand {
            display: flex;
            align-items: center;
            gap: var(--space-2);
            margin-right: var(--space-2);
        }

        .nav-logo {
            height: 32px;
            width: auto;
            object-fit: contain;
        }

        .nav-company-name {
            font-family: 'Space Grotesk', sans-serif;
            font-size: 0.875rem;
            font-weight: 600;
            color: var(--text-primary);
            white-space: nowrap;
        }

        .home-btn {
            font-size: 1.25rem;
            padding: var(--space-1) var(--space-2);
        }

        .overview-logo-container {
            margin-bottom: var(--space-4);
        }

        .overview-logo {
            width: 200px;
            height: 200px;
            object-fit: contain;
        }

        .overview-company-name {
            font-family: 'Space Grotesk', sans-serif;
            font-size: clamp(2rem, 5vw, 3rem);
            font-weight: 700;
            color: var(--text-primary);
            margin-bottom: var(--space-4);
            letter-spacing: -0.02em;
        }

        .slide-select-wrapper {
            position: relative;
        }

        .slide-select {
            appearance: none;
            -webkit-appearance: none;
            padding: var(--space-1) var(--space-3);
            padding-right: 2rem;
            background: var(--glass-bg);
            border: 1px solid var(--glass-border);
            color: var(--text-primary);
            border-radius: 0.5rem;
            font-size: 0.875rem;
            cursor: pointer;
            transition: all 0.2s ease;
            min-width: 180px;
        }

        .slide-select:hover {
            background: rgba(255, 255, 255, 0.15);
            border-color: var(--electron);
        }

        .slide-select:focus {
            outline: none;
            border-color: var(--electron);
        }

        .slide-select option {
            background: #1e293b;
            color: var(--text-primary);
            padding: var(--space-2);
        }

        .slide-counter {
            font-size: 1.25rem;
            font-weight: 700;
            color: var(--electron);
        }

        .nav-buttons {
            display: flex;
            gap: var(--space-2);
        }

        .nav-btn {
            padding: var(--space-1) var(--space-3);
            background: var(--glass-bg);
            border: 1px solid var(--glass-border);
            color: var(--text-primary);
            border-radius: 0.5rem;
            cursor: pointer;
            font-size: 0.875rem;
            transition: all 0.2s ease;
        }

        .nav-btn:hover {
            background: rgba(255, 255, 255, 0.15);
            border-color: var(--electron);
        }

        .nav-btn:disabled {
            opacity: 0.3;
            cursor: not-allowed;
        }

        .keyboard-hints {
            font-size: 0.75rem;
            color: var(--text-secondary);
        }

        .keyboard-hints kbd {
            background: var(--glass-bg);
            border: 1px solid var(--glass-border);
            border-radius: 4px;
            padding: 2px 6px;
            margin: 0 2px;
        }

        /* Main Split Layout */
        .main-container {
            position: fixed;
            top: 60px;
            left: 0;
            right: 0;
            bottom: 40px;
            display: flex;
        }

        .teacher-panel-header {
            font-size: 0.75rem;
            color: var(--electron);
            text-transform: uppercase;
            letter-spacing: 1px;
            margin-bottom: var(--space-3);
            padding-bottom: var(--space-1);
            border-bottom: 1px solid var(--glass-border);
        }

        /* Teacher Guidance Sections */
        .guidance-section {
            margin-bottom: var(--space-3);
            padding: var(--space-2);
            background: var(--glass-bg);
            border: 1px solid var(--glass-border);
            border-radius: 0.75rem;
            border-left: 3px solid var(--electron);
        }

        .guidance-section.interaction {
            border-left-color: var(--success);
        }

        .guidance-section.watch {
            border-left-color: var(--proton);
        }

        .section-title {
            font-size: 0.8rem;
            font-weight: 700;
            color: var(--electron);
            margin-bottom: var(--space-1);
            text-transform: uppercase;
            letter-spacing: 0.5px;
        }

        .section-bullets {
            list-style: none;
        }

        .section-bullets li {
            font-size: 0.875rem;
            line-height: 1.5;
            margin-bottom: 6px;
            padding-left: var(--space-2);
            position: relative;
            color: var(--text-primary);
        }

        .section-bullets li::before {
            content: "•";
            position: absolute;
            left: 0;
            color: var(--text-secondary);
        }

        .section-bullets li:last-child {
            margin-bottom: 0;
        }

        /* Spoken/Non-Spoken Text Classes */
        .spoken {
            color: #ff8c00;
            font-weight: 700;
        }

        .non-spoken {
            color: #87CEEB;  /* Light blue for non-spoken content */
        }

        .heading {
            color: #eab308;
        }

        /* Tab Interface Styles */
        .tab-container {
            margin-bottom: var(--space-3);
        }

        .tab-list {
            display: flex;
            gap: var(--space-1);
            border-bottom: 1px solid var(--glass-border);
            margin-bottom: var(--space-2);
        }

        .tab-btn {
            padding: var(--space-1) var(--space-2);
            background: transparent;
            border: none;
            border-bottom: 2px solid transparent;
            color: var(--text-secondary);
            cursor: pointer;
            font-size: 0.8rem;
            font-weight: 600;
            transition: all 0.2s ease;
        }

        .tab-btn:hover {
            color: var(--text-primary);
        }

        .tab-btn[aria-selected="true"] {
            color: var(--electron);
            border-bottom-color: var(--electron);
        }

        .tab-panel {
            display: none;
        }

        .tab-panel[aria-hidden="false"] {
            display: block;
        }

        /* LHS Tab Interface */
        .lhs-tab-list {
            display: flex;
            gap: var(--space-1);
            padding: var(--space-2) var(--space-3);
            background: rgba(2, 6, 23, 0.8);
            border-bottom: 1px solid var(--glass-border);
        }

        .lhs-tab-btn {
            padding: var(--space-1) var(--space-2);
            background: transparent;
            border: none;
            border-bottom: 2px solid transparent;
            color: var(--text-secondary);
            cursor: pointer;
            font-size: 0.8rem;
            font-weight: 600;
            transition: all 0.2s ease;
        }

        .lhs-tab-btn:hover {
            color: var(--text-primary);
        }

        .lhs-tab-btn.active {
            color: var(--electron);
            border-bottom-color: var(--electron);
        }

        /* Pause/Wait Cues */
        .cue-pause {
            color: var(--success);
            font-weight: 600;
        }

        .cue-wait {
            color: var(--neutron);
            font-weight: 600;
        }

        /* Bottom Progress Bar */
        .bottom-bar {
            position: fixed;
            bottom: 0;
            left: 0;
            right: 0;
            height: 40px;
            display: flex;
            align-items: center;
            padding: 0 var(--space-4);
            background: rgba(2, 6, 23, 0.95);
            border-top: 1px solid var(--glass-border);
        }

        .progress-container {
            flex: 1;
            height: 8px;
            background: var(--glass-bg);
            border-radius: 4px;
            overflow: hidden;
            margin-right: var(--space-3);
        }

        .progress-bar {
            height: 100%;
            background: linear-gradient(90deg, var(--electron), var(--neutron));
            transition: width 0.3s ease;
            border-radius: 4px;
        }

        .progress-label {
            font-size: 0.75rem;
            color: var(--text-secondary);
            min-width: 80px;
            text-align: right;
        }

        /* Student Slide Styles (mirrored from main_lesson_01) */
        .slide-title {
            font-size: 1.5rem;
            font-weight: 700;
            margin-bottom: var(--space-2);
            color: var(--text-primary);
        }

        .slide-title .highlight {
            color: var(--electron);
        }

        .content-card {
            padding: var(--space-3);
            margin-bottom: var(--space-2);
        }

        .atom-visual {
            display: flex;
            justify-content: center;
            align-items: center;
            gap: var(--space-3);
            margin: var(--space-2) 0;
        }

        .atom-box {
            width: 100px;
            height: 140px;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            padding: var(--space-2);
            text-align: center;
        }

        .atom-symbol {
            font-size: 2.5rem;
            font-weight: 700;
        }

        .atom-mass {
            font-size: 1.25rem;
            color: var(--text-secondary);
        }

        .atom-label {
            font-size: 0.75rem;
            color: var(--text-secondary);
            margin-top: var(--space-1);
        }

        .vs-text {
            font-size: 1.25rem;
            font-weight: 700;
            color: var(--text-secondary);
        }

        .info-box {
            padding: var(--space-2);
            margin: var(--space-2) 0;
            border-left: 4px solid var(--electron);
            background: rgba(234, 179, 8, 0.1);
        }

        .info-box p {
            margin-bottom: var(--space-1);
            line-height: 1.5;
            font-size: 0.9rem;
        }

        .particle-legend {
            display: flex;
            justify-content: center;
            gap: var(--space-3);
            margin: var(--space-2) 0;
        }

        .legend-item {
            display: flex;
            align-items: center;
            gap: var(--space-1);
            font-size: 0.8rem;
        }

        .legend-dot {
            width: 10px;
            height: 10px;
            border-radius: 50%;
        }

        .legend-dot.proton { background: var(--proton); }
        .legend-dot.neutron { background: var(--neutron); }

        .formula-box {
            background: rgba(59, 130, 246, 0.15);
            border: 2px solid var(--neutron);
            border-radius: 0.5rem;
            padding: var(--space-2);
            text-align: center;
            font-size: 1rem;
            font-family: 'Courier New', monospace;
            margin: var(--space-2) 0;
        }

        .step-list {
            list-style: none;
            counter-reset: step-counter;
        }

        .step-list li {
            counter-increment: step-counter;
            display: flex;
            align-items: flex-start;
            gap: var(--space-1);
            margin-bottom: var(--space-1);
            padding: var(--space-1);
            background: rgba(255, 255, 255, 0.03);
            border-radius: 0.5rem;
            font-size: 0.85rem;
        }

        .step-list li::before {
            content: counter(step-counter);
            min-width: 20px;
            height: 20px;
            background: var(--electron);
            color: #000;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 0.75rem;
        }

        .quiz-options {
            display: flex;
            flex-direction: column;
            gap: var(--space-1);
            margin: var(--space-2) 0;
        }

        .quiz-option {
            padding: var(--space-1) var(--space-2);
            background: rgba(255, 255, 255, 0.05);
            border: 2px solid rgba(255, 255, 255, 0.2);
            border-radius: 0.5rem;
            font-size: 0.85rem;
        }

        .calculator-app {
            background: rgba(0, 0, 0, 0.3);
            border: 2px solid var(--glass-border);
            border-radius: 1rem;
            padding: var(--space-2);
            margin: var(--space-2) 0;
        }

        .calc-row {
            display: flex;
            align-items: center;
            gap: var(--space-1);
            margin-bottom: var(--space-1);
            flex-wrap: wrap;
        }

        .calc-label {
            min-width: 140px;
            font-weight: 600;
            font-size: 0.8rem;
        }

        .calc-input {
            width: 80px;
            padding: 0.35rem;
            background: rgba(255, 255, 255, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.3);
            border-radius: 0.25rem;
            color: white;
            text-align: center;
            font-size: 0.8rem;
        }

        .btn {
            padding: var(--space-1) var(--space-2);
            border: none;
            border-radius: 0.5rem;
            font-size: 0.8rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.2s ease;
        }

        .btn-primary {
            background: var(--electron);
            color: #000;
        }

        .btn-secondary {
            background: rgba(255, 255, 255, 0.1);
            color: white;
            border: 1px solid rgba(255, 255, 255, 0.2);
        }

        .data-table {
            width: 100%;
            border-collapse: collapse;
            margin: var(--space-2) 0;
            font-size: 0.75rem;
        }

        .data-table th,
        .data-table td {
            padding: var(--space-1);
            text-align: left;
            border: 1px solid var(--glass-border);
        }

        .data-table th {
            background: rgba(255, 255, 255, 0.05);
            font-weight: 600;
        }

        .data-table .result-row {
            background: rgba(34, 197, 94, 0.1) !important;
            font-weight: 600;
        }

        .input-group {
            display: flex;
            align-items: center;
            gap: var(--space-1);
            margin: var(--space-1) 0;
        }

        .input-label {
            min-width: 120px;
            font-size: 0.8rem;
            color: var(--text-secondary);
        }

        .fill-input {
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.3);
            color: white;
            padding: 0.4rem 0.8rem;
            border-radius: 0.5rem;
            width: 100px;
            text-align: center;
            font-size: 0.85rem;
        }

        .feedback {
            margin-top: var(--space-1);
            padding: var(--space-1);
            border-radius: 0.5rem;
            font-size: 0.8rem;
        }

        .particle-tray {
            display: flex;
            justify-content: center;
            gap: var(--space-3);
            margin: var(--space-2) 0;
        }

        .particle-source {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: var(--space-1);
        }

        .particle-btn {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            cursor: grab;
        }

        .particle-btn.proton { background: var(--proton); }
        .particle-btn.neutron { background: var(--neutron); }

        .nucleus-area {
            width: 120px;
            height: 120px;
            border: 2px dashed var(--glass-border);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin: var(--space-2) auto;
        }

        .isotope-stats {
            display: flex;
            justify-content: center;
            gap: var(--space-2);
            margin: var(--space-2) 0;
        }

        .stat-box {
            text-align: center;
            padding: var(--space-1);
            background: var(--glass-bg);
            border-radius: 0.5rem;
            min-width: 60px;
        }

        .stat-value {
            font-size: 1.25rem;
            font-weight: 700;
            color: var(--electron);
        }

        .stat-label {
            font-size: 0.65rem;
            color: var(--text-secondary);
        }

        .checklist {
            list-style: none;
        }

        .checklist li {
            display: flex;
            align-items: center;
            gap: var(--space-1);
            padding: var(--space-1);
            margin-bottom: var(--space-1);
            background: rgba(255, 255, 255, 0.03);
            border-radius: 0.5rem;
            font-size: 0.85rem;
        }

        .check-box {
            width: 20px;
            height: 20px;
            border: 2px solid var(--glass-border);
            border-radius: 4px;
            cursor: pointer;
        }

        .confidence-rating {
            display: flex;
            justify-content: center;
            gap: var(--space-1);
            margin: var(--space-2) 0;
        }

        .confidence-btn {
            padding: var(--space-1);
            background: var(--glass-bg);
            border: 1px solid var(--glass-border);
            color: var(--text-primary);
            border-radius: 0.5rem;
            cursor: pointer;
            font-size: 1rem;
            font-weight: 700;
        }

        .exam-game {
            padding: var(--space-2);
        }

        .question-card {
            padding: var(--space-2);
            margin-bottom: var(--space-2);
            background: var(--glass-bg);
            border: 2px solid var(--glass-border);
            border-radius: 0.75rem;
        }

        .question-card.locked {
            opacity: 0.5;
        }

        .question-number {
            display: inline-block;
            width: 24px;
            height: 24px;
            background: var(--electron);
            color: #000;
            border-radius: 50%;
            text-align: center;
            line-height: 24px;
            font-weight: 700;
            margin-right: var(--space-1);
        }

        /* NEW: Student Mirror Panel (LHS 60%) */
        .student-mirror-panel {
            width: 60%;
            display: flex;
            flex-direction: column;
            border-right: 1px solid var(--glass-border);
            background: rgba(0, 0, 0, 0.3);
        }

        .student-mirror-header {
            padding: var(--space-2) var(--space-3);
            background: rgba(2, 6, 23, 0.8);
            border-bottom: 1px solid var(--glass-border);
            font-size: 0.875rem;
            font-weight: 600;
            color: var(--text-secondary);
            display: flex;
            align-items: center;
            gap: var(--space-2);
        }

        .mirror-icon {
            font-size: 1.1rem;
        }

        .student-mirror-content {
            flex: 1;
            padding: var(--space-3);
            overflow-y: auto;
        }

        .student-mirror-content .glass-card {
            max-width: 800px;
            margin: 0 auto;
        }

        /* NEW: Teacher Panel (RHS 40%) */
        .teacher-panel {
            width: 40%;
            display: flex;
            flex-direction: column;
            background: rgba(2, 6, 23, 0.5);
        }

        /* Locked state: LHS takes full width, RHS is hidden */
        .main-container.notes-locked .student-mirror-panel {
            width: 100%;
            border-right: none;
        }

        .main-container.notes-locked .teacher-panel {
            display: none;
        }

        /* NEW: Visual Summary Styles */
        .visual-summary {
            padding: var(--space-2);
        }

        .visual-summary-box {
            background: var(--glass-bg);
            border: 1px solid var(--glass-border);
            border-radius: 0.75rem;
            padding: var(--space-3);
            margin-bottom: var(--space-2);
        }

        .visual-summary-title {
            font-size: 1rem;
            font-weight: 700;
            color: var(--electron);
            margin-bottom: var(--space-2);
            display: flex;
            align-items: center;
            gap: var(--space-1);
        }

        .visual-summary-emoji {
            font-size: 1.5rem;
        }

        .visual-summary-svg {
            display: flex;
            justify-content: center;
            margin: var(--space-2) 0;
        }

        .visual-summary-keypoint {
            display: flex;
            align-items: flex-start;
            gap: var(--space-2);
            margin-bottom: var(--space-1);
            font-size: 0.8rem;
            color: var(--text-primary);
        }

        .visual-summary-keypoint::before {
            content: "•";
            color: var(--electron);
            font-weight: bold;
        }

        .color-box {
            display: inline-block;
            padding: 2px 8px;
            border-radius: 4px;
            font-weight: 600;
            font-size: 0.75rem;
        }
        .color-box.red { background: rgba(239, 68, 68, 0.3); color: var(--proton); }
        .color-box.blue { background: rgba(59, 130, 246, 0.3); color: var(--neutron); }
        .color-box.yellow { background: rgba(234, 179, 8, 0.3); color: var(--electron); }
        .color-box.green { background: rgba(34, 197, 94, 0.3); color: var(--success); }

        /* ==================== NEW INTRO SLIDE STYLES ==================== */

        /* Build an Atom Activity */
        .build-atom-container {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: var(--space-3);
        }

        .atom-diagram {
            position: relative;
            width: 200px;
            height: 200px;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .electron-orbit {
            position: absolute;
            border: 2px dashed rgba(234, 179, 8, 0.4);
            border-radius: 50%;
        }

        .electron-orbit:nth-child(1) { width: 120px; height: 120px; }
        .electron-orbit:nth-child(2) { width: 160px; height: 160px; }
        .electron-orbit:nth-child(3) { width: 200px; height: 200px; }

        .nucleus-center {
            width: 60px;
            height: 60px;
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid var(--glass-border);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 0.7rem;
            color: var(--text-secondary);
            z-index: 2;
        }

        .particle-label-row {
            display: flex;
            justify-content: center;
            gap: var(--space-3);
            flex-wrap: wrap;
        }

        .particle-label-item {
            display: flex;
            align-items: center;
            gap: var(--space-1);
            font-size: 0.85rem;
            font-weight: 600;
        }

        .particle-label-icon {
            width: 28px;
            height: 28px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 0.7rem;
        }

        .particle-label-icon.proton { background: var(--proton); }
        .particle-label-icon.neutron { background: var(--neutron); }
        .particle-label-icon.electron { background: var(--electron); }

        .identify-choices {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: var(--space-2);
            width: 100%;
            max-width: 350px;
        }

        .identify-choice {
            padding: var(--space-2);
            background: rgba(255, 255, 255, 0.05);
            border: 2px solid rgba(255, 255, 255, 0.2);
            border-radius: 0.5rem;
            text-align: center;
            cursor: pointer;
            transition: all 0.2s ease;
            font-size: 0.85rem;
        }

        .identify-choice:hover {
            border-color: var(--electron);
            background: rgba(234, 179, 8, 0.1);
        }

        .identify-choice.correct {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.2);
        }

        .identify-choice.incorrect {
            border-color: var(--error);
            background: rgba(239, 68, 68, 0.2);
        }

        /* Particle Calculator Activity */
        .particle-calc-container {
            display: flex;
            flex-direction: column;
            gap: var(--space-3);
        }

        .notation-diagram {
            text-align: center;
            padding: var(--space-3);
            background: rgba(59, 130, 246, 0.1);
            border: 2px solid var(--neutron);
            border-radius: 0.75rem;
            position: relative;
        }

        .notation-large {
            font-size: 2.5rem;
            font-weight: 700;
            font-family: 'Courier New', monospace;
            line-height: 1.2;
        }

        .notation-labels {
            display: flex;
            justify-content: center;
            gap: var(--space-4);
            margin-top: var(--space-2);
            font-size: 0.75rem;
            color: var(--text-secondary);
        }

        .notation-labels span {
            display: flex;
            align-items: center;
            gap: 4px;
        }

        .calc-input-row {
            display: flex;
            align-items: center;
            gap: var(--space-2);
            padding: var(--space-2);
            background: var(--glass-bg);
            border-radius: 0.5rem;
        }

        .calc-input-row label {
            min-width: 100px;
            font-size: 0.85rem;
            font-weight: 600;
        }

        .calc-result-box {
            text-align: center;
            padding: var(--space-2);
            background: rgba(34, 197, 94, 0.1);
            border: 2px solid var(--success);
            border-radius: 0.5rem;
            font-weight: 700;
            font-size: 1rem;
            color: var(--success);
            display: none;
        }

        .calc-result-box.show {
            display: block;
        }

        .calc-next-btn {
            margin-top: var(--space-2);
        }

        /* Atom Comparison Activity */
        .atom-compare-container {
            display: flex;
            flex-direction: column;
            gap: var(--space-3);
        }

        .atom-compare-grid {
            display: grid;
            grid-template-columns: 1fr auto 1fr;
            gap: var(--space-2);
            align-items: start;
        }

        .atom-compare-card {
            padding: var(--space-3);
            background: var(--glass-bg);
            border: 2px solid var(--glass-border);
            border-radius: 0.75rem;
            text-align: center;
        }

        .atom-compare-card h4 {
            font-size: 1.25rem;
            margin-bottom: var(--space-2);
        }

        .atom-compare-card .compare-symbol {
            font-size: 2rem;
            font-weight: 700;
            margin-bottom: var(--space-1);
        }

        .atom-compare-vs {
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--text-secondary);
            padding-top: var(--space-4);
        }

        .compare-detail-list {
            list-style: none;
            text-align: left;
            font-size: 0.8rem;
        }

        .compare-detail-list li {
            padding: 4px 0;
            border-bottom: 1px solid var(--glass-border);
            display: flex;
            justify-content: space-between;
        }

        .compare-detail-list li:last-child {
            border-bottom: none;
        }

        .highlight-same {
            background: rgba(34, 197, 94, 0.15);
            border-left: 3px solid var(--success);
            padding-left: var(--space-1);
        }

        .highlight-different {
            background: rgba(239, 68, 68, 0.15);
            border-left: 3px solid var(--error);
            padding-left: var(--space-1);
        }

        .mystery-question {
            text-align: center;
            padding: var(--space-3);
            background: rgba(234, 179, 8, 0.1);
            border: 2px solid var(--electron);
            border-radius: 0.75rem;
            font-size: 1rem;
        }

        .compare-answer-btns {
            display: flex;
            justify-content: center;
            gap: var(--space-2);
            margin-top: var(--space-2);
        }

        .compare-answer-btn {
            padding: var(--space-1) var(--space-3);
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.2);
            border-radius: 0.5rem;
            color: var(--text-primary);
            cursor: pointer;
            font-weight: 600;
            transition: all 0.2s ease;
        }

        .compare-answer-btn:hover {
            border-color: var(--electron);
        }

        .compare-answer-btn.correct {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.3);
        }

        .compare-answer-btn.incorrect {
            border-color: var(--error);
            background: rgba(239, 68, 68, 0.3);
        }

        /* NEW: Transcript Section */
        .transcript-section {
            flex: 1;
            display: none;
            flex-direction: column;
            background: rgba(2, 6, 23, 0.7);
            overflow: hidden;
            min-height: 0;
        }

        .transcript-section.unlocked {
            display: flex;
        }

        .teacher-notes-lock-section {
            margin-bottom: var(--space-3);
            padding: var(--space-2) var(--space-3);
        }

        .teacher-notes-lock-box {
            background: var(--glass-bg);
            border: 1px solid var(--glass-border);
            border-radius: 0.75rem;
            padding: var(--space-3);
        }

        .teacher-notes-lock-label {
            font-size: 0.8rem;
            font-weight: 700;
            color: var(--electron);
            text-transform: uppercase;
            letter-spacing: 0.5px;
            margin-bottom: var(--space-2);
        }

        .teacher-notes-lock-row {
            display: flex;
            gap: var(--space-2);
            align-items: center;
        }

        .teacher-notes-lock-input {
            flex: 1;
            padding: var(--space-1) var(--space-2);
            background: rgba(255, 255, 255, 0.1);
            border: 1px solid rgba(255, 255, 255, 0.3);
            border-radius: 0.5rem;
            color: var(--text-primary);
            font-size: 0.85rem;
            font-family: 'Courier New', monospace;
        }

        .teacher-notes-lock-input:focus {
            outline: none;
            border-color: var(--electron);
        }

        .teacher-notes-lock-btn {
            padding: var(--space-1) var(--space-2);
            background: var(--electron);
            color: #000;
            border: none;
            border-radius: 0.5rem;
            font-size: 0.8rem;
            font-weight: 700;
            cursor: pointer;
            transition: all 0.2s ease;
            white-space: nowrap;
        }

        .teacher-notes-lock-btn:hover {
            background: #fbbf24;
        }

        .teacher-notes-lock-feedback {
            margin-top: var(--space-1);
            font-size: 0.75rem;
            color: var(--error);
            min-height: 1.2em;
        }

        .transcript-header {
            padding: var(--space-2) var(--space-3);
            font-size: 0.75rem;
            font-weight: 700;
            text-transform: uppercase;
            letter-spacing: 1px;
            color: var(--text-secondary);
            display: flex;
            align-items: center;
            gap: var(--space-2);
        }

        .transcript-icon {
            font-size: 0.9rem;
        }

        .transcript-content {
            flex: 1;
            overflow-y: auto;
            padding: 0 var(--space-3) var(--space-3);
            font-size: 0.85rem;
            line-height: 1.6;
            min-height: 0;
        }

        .transcript-block {
            margin-bottom: var(--space-3);
            padding: var(--space-2);
            background: var(--glass-bg);
            border-radius: 0.5rem;
            border-left: 3px solid var(--electron);
        }

        .transcript-block-title {
            font-size: 0.7rem;
            font-weight: 700;
            text-transform: uppercase;
            color: var(--electron);
            margin-bottom: var(--space-1);
        }

        .spoken-text {
            color: #ff8c00;
            font-weight: 600;
        }

        .non-spoken-text {
            color: #87CEEB;
        }

        /* ==================== Interactive Activity Styles ==================== */

        .interactive-section {
            max-width: 800px;
            margin: var(--space-4) auto;
            padding: var(--space-4);
            background: rgba(0, 0, 0, 0.3);
            border-radius: 1rem;
            border: 2px solid var(--glass-border);
        }

        /* SLIDE 1: Emoji Reaction Poll */
        .emoji-poll {
            display: flex;
            justify-content: center;
            gap: var(--space-4);
            margin: var(--space-4) 0;
        }

        .emoji-btn {
            font-size: 3rem;
            cursor: pointer;
            transition: all 0.3s ease;
            filter: grayscale(0.5);
        }

        .emoji-btn:hover {
            transform: scale(1.3);
            filter: grayscale(0);
        }

        .emoji-btn.selected {
            transform: scale(1.4);
            filter: grayscale(0) drop-shadow(0 0 15px rgba(234, 179, 8, 0.8));
        }

        .poll-results {
            display: flex;
            flex-direction: column;
            gap: var(--space-2);
            margin-top: var(--space-3);
        }

        .poll-bar {
            display: flex;
            align-items: center;
            gap: var(--space-2);
        }

        .poll-bar-label { font-size: 2rem; min-width: 60px; }
        .poll-bar-track {
            flex: 1;
            height: 20px;
            background: rgba(255, 255, 255, 0.1);
            border-radius: 10px;
            overflow: hidden;
        }

        .poll-bar-fill {
            height: 100%;
            background: var(--electron);
            width: 0%;
            transition: width 0.5s ease;
        }

        /* SLIDE 2: Matching Game */
        .matching-area {
            display: flex;
            gap: var(--space-4);
            justify-content: space-around;
            margin: var(--space-4) 0;
        }

        .match-column {
            flex: 1;
            display: flex;
            flex-direction: column;
            gap: var(--space-2);
        }

        .match-label {
            font-size: 0.875rem;
            color: var(--text-secondary);
            text-align: center;
            margin-bottom: var(--space-1);
        }

        .match-item {
            padding: var(--space-2);
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.2);
            border-radius: 0.5rem;
            cursor: grab;
            text-align: center;
            font-weight: 600;
            transition: all 0.2s ease;
        }

        .match-item:hover { border-color: var(--electron); transform: scale(1.05); }
        .match-item.dragging { opacity: 0.5; }
        .match-item.matched { border-color: var(--success); background: rgba(34, 197, 94, 0.2); cursor: default; }
        .match-item.wrong { border-color: var(--error); animation: shake 0.3s ease; }

        @keyframes shake {
            0%, 100% { transform: translateX(0); }
            25% { transform: translateX(-5px); }
            75% { transform: translateX(5px); }
        }

        .match-target {
            padding: var(--space-2);
            min-height: 60px;
            border: 2px dashed rgba(255, 255, 255, 0.3);
            border-radius: 0.5rem;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .match-target.drag-over { border-color: var(--electron); background: rgba(234, 179, 8, 0.1); }

        /* SLIDE 3: Decision Spinner */
        .spinner-container {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: var(--space-4);
        }

        .spinner-wheel {
            width: 200px;
            height: 200px;
            border-radius: 50%;
            background: conic-gradient(
                var(--proton) 0deg 90deg,
                var(--neutron) 90deg 180deg,
                var(--electron) 180deg 270deg,
                var(--success) 270deg 360deg
            );
            display: flex;
            align-items: center;
            justify-content: center;
            position: relative;
            transition: transform 3s ease-out;
        }

        .spinner-wheel.spinning {
            transform: rotate(1800deg);
        }

        .spinner-center {
            width: 60px;
            height: 60px;
            background: var(--bg-dark);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 1.5rem;
        }

        .spinner-pointer {
            position: absolute;
            top: -20px;
            width: 0;
            height: 0;
            border-left: 15px solid transparent;
            border-right: 15px solid transparent;
            border-top: 25px solid var(--text-primary);
        }

        .spinner-options {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: var(--space-2);
            width: 100%;
            max-width: 300px;
        }

        .spinner-option {
            padding: var(--space-2);
            text-align: center;
            font-weight: 600;
            border-radius: 0.5rem;
            transition: all 0.2s ease;
        }

        .spinner-option.selected {
            background: rgba(234, 179, 8, 0.3);
            border: 2px solid var(--electron);
        }

        /* SLIDE 4: Interactive Slider */
        .slider-container {
            margin: var(--space-4) 0;
        }

        .ratio-slider {
            width: 100%;
            height: 20px;
            -webkit-appearance: none;
            background: linear-gradient(90deg, var(--proton), var(--neutron));
            border-radius: 10px;
            outline: none;
        }

        .ratio-slider::-webkit-slider-thumb {
            -webkit-appearance: none;
            width: 40px;
            height: 40px;
            border-radius: 50%;
            background: var(--electron);
            cursor: pointer;
            box-shadow: 0 0 15px rgba(234, 179, 8, 0.5);
        }

        .balance-visual {
            display: flex;
            justify-content: center;
            align-items: center;
            margin: var(--space-4) 0;
            gap: var(--space-4);
        }

        .balance-beam {
            width: 250px;
            height: 10px;
            background: linear-gradient(90deg, var(--proton), var(--electron));
            border-radius: 5px;
            position: relative;
            transition: transform 0.3s ease;
            transform-origin: center center;
        }

        .balance-fulcrum {
            position: absolute;
            left: 50%;
            top: 100%;
            transform: translateX(-50%);
            width: 0;
            height: 0;
            border-left: 20px solid transparent;
            border-right: 20px solid transparent;
            border-bottom: 30px solid var(--text-secondary);
        }

        .balance-pan {
            position: absolute;
            top: -60px;
            width: 80px;
            height: 40px;
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.3);
            border-radius: 0 0 40px 40px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 1.5rem;
            transition: all 0.3s ease;
        }

        .balance-pan.left { left: 0; }
        .balance-pan.right { right: 0; }

        .ratio-display {
            text-align: center;
            font-size: 1.5rem;
            font-weight: 700;
            margin-bottom: var(--space-3);
        }

        .ratio-display .cl-35 { color: var(--proton); }
        .ratio-display .cl-37 { color: var(--neutron); }
        .ratio-display .avg { color: var(--electron); font-size: 2rem; }

        /* SLIDE 5: Formula Puzzle Builder */
        .formula-puzzle {
            margin: var(--space-4) 0;
        }

        .puzzle-pieces {
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-2);
            justify-content: center;
            margin-bottom: var(--space-3);
            padding: var(--space-3);
            background: rgba(0, 0, 0, 0.2);
            border-radius: 0.5rem;
            min-height: 80px;
        }

        .puzzle-piece {
            padding: var(--space-2) var(--space-3);
            background: rgba(59, 130, 246, 0.3);
            border: 2px solid var(--neutron);
            border-radius: 0.5rem;
            cursor: grab;
            font-family: 'Courier New', monospace;
            font-weight: 600;
            transition: all 0.2s ease;
        }

        .puzzle-piece:hover { transform: scale(1.1); border-color: var(--electron); }
        .puzzle-piece.selected { background: rgba(234, 179, 8, 0.3); border-color: var(--electron); }

        .puzzle-slot {
            display: inline-block;
            min-width: 80px;
            padding: var(--space-2);
            margin: var(--space-1);
            border: 2px dashed rgba(255, 255, 255, 0.3);
            border-radius: 0.5rem;
            text-align: center;
            font-family: 'Courier New', monospace;
            transition: all 0.2s ease;
        }

        .puzzle-slot.filled {
            border-style: solid;
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.1);
        }

        .puzzle-target {
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-1);
            justify-content: center;
            padding: var(--space-3);
            background: rgba(0, 0, 0, 0.3);
            border-radius: 0.5rem;
        }

        /* SLIDE 6: Step Calculator */
        .step-calculator {
            background: rgba(0, 0, 0, 0.3);
            border-radius: 1rem;
            padding: var(--space-4);
        }

        .calc-step-row {
            display: flex;
            align-items: center;
            gap: var(--space-2);
            padding: var(--space-2);
            margin-bottom: var(--space-2);
            background: rgba(255, 255, 255, 0.05);
            border-radius: 0.5rem;
            overflow: hidden;
        }

        .calc-step-num {
            width: 30px;
            height: 30px;
            background: var(--electron);
            color: #000;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            flex-shrink: 0;
        }

        .calc-step-content {
            flex: 1;
            font-family: 'Courier New', monospace;
            padding: var(--space-2);
            background: rgba(0, 0, 0, 0.2);
            border-radius: 0.25rem;
        }

        .calc-step-reveal {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.5s ease;
            color: var(--success);
            font-weight: 600;
            padding-left: 42px;
        }

        .calc-step-reveal.show {
            max-height: 50px;
            padding-top: var(--space-1);
        }

        .reveal-btn {
            margin-top: var(--space-3);
            width: 100%;
        }

        /* SLIDE 7: Step Sorter */
        .step-sorter {
            margin: var(--space-4) 0;
        }

        .scrambled-steps {
            display: flex;
            flex-direction: column;
            gap: var(--space-2);
            margin-bottom: var(--space-4);
            padding: var(--space-3);
            background: rgba(0, 0, 0, 0.2);
            border-radius: 0.5rem;
            min-height: 200px;
        }

        .sort-step {
            padding: var(--space-2) var(--space-3);
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.2);
            border-radius: 0.5rem;
            cursor: grab;
            display: flex;
            align-items: center;
            gap: var(--space-2);
            transition: all 0.2s ease;
        }

        .sort-step:hover { border-color: var(--electron); transform: scale(1.02); }
        .sort-step.dragging { opacity: 0.5; }
        .sort-step.in-place {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.1);
        }

        .sort-step .step-num-badge {
            width: 24px;
            height: 24px;
            background: var(--electron);
            color: #000;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 0.75rem;
        }

        .sort-step.in-place .step-num-badge {
            background: var(--success);
        }

        .target-sequence {
            display: flex;
            flex-direction: column;
            gap: var(--space-2);
            padding: var(--space-3);
            background: rgba(0, 0, 0, 0.3);
            border-radius: 0.5rem;
            min-height: 200px;
        }

        .target-slot {
            padding: var(--space-2) var(--space-3);
            min-height: 50px;
            border: 2px dashed rgba(255, 255, 255, 0.3);
            border-radius: 0.5rem;
            display: flex;
            align-items: center;
        }

        .target-slot.drag-over { border-color: var(--electron); background: rgba(234, 179, 8, 0.1); }

        /* SLIDE 8: Typing Race */
        .typing-race {
            text-align: center;
        }

        .typing-question {
            font-size: 1.5rem;
            margin-bottom: var(--space-4);
            padding: var(--space-3);
            background: rgba(255, 255, 255, 0.05);
            border-radius: 0.5rem;
        }

        .typing-timer {
            font-size: 3rem;
            font-weight: 700;
            color: var(--electron);
            margin-bottom: var(--space-3);
            font-variant-numeric: tabular-nums;
        }

        .typing-input {
            width: 200px;
            padding: var(--space-2);
            font-size: 1.5rem;
            text-align: center;
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.3);
            border-radius: 0.5rem;
            color: white;
            margin: 0 auto var(--space-3);
        }

        .typing-input:focus {
            outline: none;
            border-color: var(--electron);
        }

        .typing-start-btn {
            font-size: 1.25rem;
            padding: var(--space-3) var(--space-5);
        }

        /* SLIDE 9: Particle Catcher */
        .particle-catcher {
            position: relative;
            height: 300px;
            background: linear-gradient(180deg, #0a1628 0%, #1e3a5f 100%);
            border-radius: 1rem;
            overflow: hidden;
            border: 2px solid var(--glass-border);
        }

        .catcher-target {
            position: absolute;
            bottom: 20px;
            left: 50%;
            transform: translateX(-50%);
            width: 150px;
            height: 50px;
            background: rgba(234, 179, 8, 0.3);
            border: 3px solid var(--electron);
            border-radius: 0 0 75px 75px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 0.875rem;
        }

        .falling-particle {
            position: absolute;
            width: 40px;
            height: 40px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 0.875rem;
            cursor: pointer;
            animation: fallDown 3s linear forwards;
            transition: transform 0.1s ease;
        }

        .falling-particle:hover { transform: scale(1.2); }

        .falling-particle.proton {
            background: var(--proton);
            color: white;
        }

        .falling-particle.neutron {
            background: var(--neutron);
            color: white;
        }

        @keyframes fallDown {
            from { top: -50px; }
            to { top: 350px; }
        }

        .catcher-score {
            position: absolute;
            top: 10px;
            right: 10px;
            font-size: 1.25rem;
            font-weight: 700;
        }

        .catcher-instructions {
            position: absolute;
            top: 10px;
            left: 10px;
            font-size: 0.875rem;
            color: var(--text-secondary);
        }

        /* SLIDE 10: Card Flip */
        .card-flip {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: var(--space-4);
        }

        .flip-card {
            width: 300px;
            height: 180px;
            perspective: 1000px;
            cursor: pointer;
        }

        .flip-card-inner {
            position: relative;
            width: 100%;
            height: 100%;
            transition: transform 0.6s;
            transform-style: preserve-3d;
        }

        .flip-card.flipped .flip-card-inner {
            transform: rotateY(180deg);
        }

        .flip-card-front, .flip-card-back {
            position: absolute;
            width: 100%;
            height: 100%;
            backface-visibility: hidden;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            border-radius: 1rem;
            padding: var(--space-3);
        }

        .flip-card-front {
            background: linear-gradient(135deg, rgba(59, 130, 246, 0.3), rgba(239, 68, 68, 0.3));
            border: 2px solid var(--glass-border);
        }

        .flip-card-front .card-icon {
            font-size: 4rem;
            margin-bottom: var(--space-2);
        }

        .flip-card-back {
            background: rgba(0, 0, 0, 0.5);
            border: 2px solid var(--glass-border);
            transform: rotateY(180deg);
        }

        .flip-card-back .result-icon {
            font-size: 4rem;
            margin-bottom: var(--space-2);
        }

        .flip-card-back .result-text {
            font-size: 1.25rem;
            font-weight: 700;
            margin-bottom: var(--space-2);
        }

        .flip-card-back .explanation {
            font-size: 0.875rem;
            color: var(--text-secondary);
            text-align: center;
        }

        .click-hint {
            font-size: 0.875rem;
            color: var(--text-secondary);
        }

        /* SLIDE 11: Fill-in-the-Blanks Animator */
        .fill-blanks {
            margin: var(--space-4) 0;
        }

        .blank-row {
            display: flex;
            align-items: center;
            gap: var(--space-2);
            padding: var(--space-2);
            margin-bottom: var(--space-2);
            background: rgba(255, 255, 255, 0.05);
            border-radius: 0.5rem;
            opacity: 0.5;
            transform: translateX(-20px);
            transition: all 0.4s ease;
        }

        .blank-row.active {
            opacity: 1;
            transform: translateX(0);
            border-left: 3px solid var(--electron);
        }

        .blank-row.completed {
            opacity: 1;
            border-left: 3px solid var(--success);
        }

        .blank-row .row-label {
            font-weight: 600;
            min-width: 80px;
        }

        .blank-input {
            flex: 1;
            max-width: 100px;
            padding: var(--space-1) var(--space-2);
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.3);
            border-radius: 0.25rem;
            color: white;
            text-align: center;
            font-family: 'Courier New', monospace;
        }

        .blank-input:focus {
            outline: none;
            border-color: var(--electron);
        }

        .blank-input.correct {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.2);
        }

        .blank-input.incorrect {
            border-color: var(--error);
            background: rgba(239, 68, 68, 0.2);
        }

        .blank-row .result {
            min-width: 120px;
            font-family: 'Courier New', monospace;
        }

        .blank-nav-btns {
            display: flex;
            gap: var(--space-2);
            justify-content: center;
            margin-top: var(--space-3);
        }

        /* SLIDE 12: Hint Ladder */
        .hint-ladder {
            margin: var(--space-4) 0;
        }

        .hint-step {
            display: flex;
            align-items: center;
            gap: var(--space-3);
            padding: var(--space-3);
            margin-bottom: var(--space-2);
            background: rgba(255, 255, 255, 0.05);
            border-radius: 0.5rem;
            cursor: pointer;
            transition: all 0.2s ease;
        }

        .hint-step:hover { background: rgba(255, 255, 255, 0.1); }
        .hint-step.locked { opacity: 0.5; cursor: not-allowed; }
        .hint-step.revealed { border-left: 3px solid var(--electron); }

        .hint-cost {
            width: 40px;
            height: 40px;
            background: var(--electron);
            color: #000;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            flex-shrink: 0;
        }

        .hint-step.locked .hint-cost {
            background: rgba(255, 255, 255, 0.2);
            color: var(--text-secondary);
        }

        .hint-text {
            flex: 1;
            font-size: 0.875rem;
        }

        .hint-reveal-area {
            margin-top: var(--space-4);
            padding: var(--space-3);
            background: rgba(234, 179, 8, 0.1);
            border: 2px solid var(--electron);
            border-radius: 0.5rem;
            min-height: 60px;
        }

        .points-display-hint {
            font-size: 1.25rem;
            font-weight: 700;
            text-align: center;
            margin-bottom: var(--space-3);
        }

        .points-display-hint span { color: var(--electron); }

        /* SLIDE 13: Boss Health Bar */
        .boss-game {
            text-align: center;
        }

        .boss-container {
            position: relative;
            margin: var(--space-4) 0;
            padding: var(--space-4);
            background: linear-gradient(180deg, #1a0a0a 0%, #2d1515 100%);
            border-radius: 1rem;
            border: 2px solid var(--error);
        }

        .boss-health-bar {
            height: 30px;
            background: rgba(255, 255, 255, 0.1);
            border-radius: 15px;
            overflow: hidden;
            margin-bottom: var(--space-3);
        }

        .boss-health-fill {
            height: 100%;
            background: linear-gradient(90deg, var(--error), #ff6b6b);
            width: 100%;
            transition: width 0.5s ease;
        }

        .boss-name {
            font-size: 1.5rem;
            font-weight: 700;
            margin-bottom: var(--space-2);
        }

        .boss-emoji {
            font-size: 5rem;
            margin-bottom: var(--space-2);
            animation: bossBounce 1s ease infinite;
        }

        @keyframes bossBounce {
            0%, 100% { transform: translateY(0); }
            50% { transform: translateY(-10px); }
        }

        .boss-status {
            font-size: 1rem;
            color: var(--text-secondary);
        }

        .boss-question {
            margin: var(--space-3) 0;
            padding: var(--space-3);
            background: rgba(0, 0, 0, 0.3);
            border-radius: 0.5rem;
        }

        .boss-options {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: var(--space-2);
        }

        .boss-option {
            padding: var(--space-2);
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.2);
            border-radius: 0.5rem;
            cursor: pointer;
            transition: all 0.2s ease;
        }

        .boss-option:hover:not(:disabled) {
            border-color: var(--electron);
            transform: scale(1.05);
        }

        .boss-option:disabled { opacity: 0.5; cursor: not-allowed; }

        .boss-damage-effect {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            font-size: 3rem;
            font-weight: 700;
            opacity: 0;
            animation: damagePopup 0.8s ease forwards;
        }

        .boss-damage-effect.correct { color: var(--success); }
        .boss-damage-effect.wrong { color: var(--error); }

        @keyframes damagePopup {
            0% { opacity: 0; transform: translate(-50%, -50%) scale(0.5); }
            50% { opacity: 1; transform: translate(-50%, -50%) scale(1.5); }
            100% { opacity: 0; transform: translate(-50%, -50%) scale(2); }
        }

        /* SLIDE 14: Drag-to-Complete */
        .drag-complete {
            margin: var(--space-4) 0;
        }

        .drag-source {
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-2);
            padding: var(--space-3);
            background: rgba(0, 0, 0, 0.2);
            border-radius: 0.5rem;
            margin-bottom: var(--space-3);
            min-height: 80px;
        }

        .drag-card {
            padding: var(--space-2) var(--space-3);
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.2);
            border-radius: 0.5rem;
            cursor: grab;
            transition: all 0.2s ease;
            font-size: 0.875rem;
        }

        .drag-card:hover {
            border-color: var(--electron);
            transform: scale(1.05);
        }

        .drag-card.dragging { opacity: 0.5; }
        .drag-card.completed { opacity: 0.3; cursor: default; }

        .drag-target-zone {
            padding: var(--space-4);
            background: rgba(34, 197, 94, 0.1);
            border: 3px dashed var(--success);
            border-radius: 1rem;
            min-height: 120px;
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-2);
            align-items: flex-start;
        }

        .drag-target-zone.drag-over {
            background: rgba(34, 197, 94, 0.2);
            border-style: solid;
        }

        .drag-target-zone .zone-label {
            width: 100%;
            text-align: center;
            font-weight: 700;
            color: var(--success);
            margin-bottom: var(--space-2);
        }

        .drag-target-zone .drag-card {
            background: rgba(34, 197, 94, 0.2);
            border-color: var(--success);
        }

        /* SLIDE 15: Confetti Celebration */
        .celebration {
            text-align: center;
            padding: var(--space-4);
        }

        .celebration-emoji {
            font-size: 5rem;
            margin-bottom: var(--space-3);
            animation: celebrateBounce 0.5s ease infinite;
        }

        @keyframes celebrateBounce {
            0%, 100% { transform: scale(1); }
            50% { transform: scale(1.1); }
        }

        .celebration-btn {
            font-size: 1.5rem;
            padding: var(--space-3) var(--space-5);
            margin-top: var(--space-3);
        }

        .confetti-container {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            pointer-events: none;
            z-index: 1000;
            overflow: hidden;
        }

        /* SLIDE 6 (NEW): Property Sorting Game */
        .property-sort-game {
            display: flex;
            flex-direction: column;
            gap: var(--space-3);
        }

        .property-sort-source {
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-2);
            justify-content: center;
            padding: var(--space-3);
            background: rgba(0, 0, 0, 0.2);
            border-radius: 0.5rem;
            min-height: 60px;
        }

        .property-tile {
            padding: var(--space-2) var(--space-3);
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.2);
            border-radius: 0.5rem;
            cursor: pointer;
            font-weight: 600;
            font-size: 0.85rem;
            transition: all 0.2s ease;
            user-select: none;
        }

        .property-tile:hover {
            border-color: var(--electron);
            transform: scale(1.05);
        }

        .property-tile.selected {
            border-color: var(--electron);
            background: rgba(234, 179, 8, 0.2);
            transform: scale(1.05);
        }

        .property-tile.sorted {
            opacity: 0.3;
            cursor: default;
            pointer-events: none;
        }

        .property-tile.correct-sort {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.2);
            opacity: 0.5;
        }

        .property-tile.wrong-sort {
            border-color: var(--error);
            animation: shake 0.3s ease;
        }

        .property-sort-bins {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: var(--space-3);
        }

        .sort-bin {
            padding: var(--space-3);
            border-radius: 0.75rem;
            min-height: 120px;
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: var(--space-1);
            cursor: pointer;
            transition: all 0.2s ease;
        }

        .sort-bin.chemical-bin {
            background: rgba(34, 197, 94, 0.1);
            border: 2px dashed var(--success);
        }

        .sort-bin.physical-bin {
            background: rgba(59, 130, 246, 0.1);
            border: 2px dashed var(--neutron);
        }

        .sort-bin:hover {
            transform: scale(1.02);
        }

        .sort-bin.chemical-bin:hover {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.2);
        }

        .sort-bin.physical-bin:hover {
            border-color: var(--neutron);
            background: rgba(59, 130, 246, 0.2);
        }

        .sort-bin-label {
            font-size: 0.9rem;
            font-weight: 700;
            text-transform: uppercase;
            letter-spacing: 0.5px;
            margin-bottom: var(--space-1);
        }

        .sort-bin.chemical-bin .sort-bin-label {
            color: var(--success);
        }

        .sort-bin.physical-bin .sort-bin-label {
            color: var(--neutron);
        }

        .sort-bin-items {
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-1);
            justify-content: center;
        }

        .sort-bin-item {
            padding: 4px 10px;
            border-radius: 0.25rem;
            font-size: 0.75rem;
            font-weight: 600;
        }

        .sort-bin.chemical-bin .sort-bin-item {
            background: rgba(34, 197, 94, 0.3);
            color: var(--success);
        }

        .sort-bin.physical-bin .sort-bin-item {
            background: rgba(59, 130, 246, 0.3);
            color: var(--neutron);
        }

        .property-sort-score {
            text-align: center;
            font-size: 0.85rem;
            color: var(--text-secondary);
        }

        .property-sort-score span {
            color: var(--electron);
            font-weight: 700;
        }

        /* Side-by-side isotope comparison for Slide 6 */
        .isotope-compare-side-by-side {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: var(--space-3);
            margin: var(--space-3) 0;
        }

        .isotope-compare-card {
            padding: var(--space-3);
            background: var(--glass-bg);
            border: 2px solid var(--glass-border);
            border-radius: 0.75rem;
            text-align: center;
        }

        .isotope-compare-card h4 {
            font-size: 1rem;
            margin-bottom: var(--space-2);
        }

        .isotope-compare-card .compare-symbol-big {
            font-size: 2.5rem;
            font-weight: 700;
            margin-bottom: var(--space-1);
        }

        .isotope-compare-card .compare-detail-list {
            list-style: none;
            text-align: left;
            font-size: 0.8rem;
        }

        .isotope-compare-card .compare-detail-list li {
            padding: 4px 0;
            border-bottom: 1px solid var(--glass-border);
            display: flex;
            justify-content: space-between;
        }

        .isotope-compare-card .compare-detail-list li:last-child {
            border-bottom: none;
        }

        .same-property {
            background: rgba(34, 197, 94, 0.1);
            border-left: 3px solid var(--success);
            padding-left: var(--space-1);
        }

        .diff-property {
            background: rgba(59, 130, 246, 0.1);
            border-left: 3px solid var(--neutron);
            padding-left: var(--space-1);
        }

        /* SLIDE 6 (NEW): Property Sorting Game */
        .property-sort-game { display: flex; flex-direction: column; gap: var(--space-3); }
        .property-sort-source { display: flex; flex-wrap: wrap; gap: var(--space-2); justify-content: center; padding: var(--space-3); background: rgba(0, 0, 0, 0.2); border-radius: 0.5rem; min-height: 60px; }
        .property-tile { padding: var(--space-2) var(--space-3); background: rgba(255, 255, 255, 0.1); border: 2px solid rgba(255, 255, 255, 0.2); border-radius: 0.5rem; cursor: pointer; font-weight: 600; font-size: 0.85rem; transition: all 0.2s ease; user-select: none; }
        .property-tile:hover { border-color: var(--electron); transform: scale(1.05); }
        .property-tile.selected { border-color: var(--electron); background: rgba(234, 179, 8, 0.2); transform: scale(1.05); }
        .property-tile.sorted { opacity: 0.3; cursor: default; pointer-events: none; }
        .property-tile.correct-sort { border-color: var(--success); background: rgba(34, 197, 94, 0.2); opacity: 0.5; }
        .property-tile.wrong-sort { border-color: var(--error); animation: shake 0.3s ease; }
        .property-sort-bins { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-3); }
        .sort-bin { padding: var(--space-3); border-radius: 0.75rem; min-height: 120px; display: flex; flex-direction: column; align-items: center; gap: var(--space-1); cursor: pointer; transition: all 0.2s ease; }
        .sort-bin.chemical-bin { background: rgba(34, 197, 94, 0.1); border: 2px dashed var(--success); }
        .sort-bin.physical-bin { background: rgba(59, 130, 246, 0.1); border: 2px dashed var(--neutron); }
        .sort-bin:hover { transform: scale(1.02); }
        .sort-bin.chemical-bin:hover { border-color: var(--success); background: rgba(34, 197, 94, 0.2); }
        .sort-bin.physical-bin:hover { border-color: var(--neutron); background: rgba(59, 130, 246, 0.2); }
        .sort-bin-label { font-size: 0.9rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.5px; margin-bottom: var(--space-1); }
        .sort-bin.chemical-bin .sort-bin-label { color: var(--success); }
        .sort-bin.physical-bin .sort-bin-label { color: var(--neutron); }
        .sort-bin-items { display: flex; flex-wrap: wrap; gap: var(--space-1); justify-content: center; }
        .sort-bin-item { padding: 4px 10px; border-radius: 0.25rem; font-size: 0.75rem; font-weight: 600; }
        .sort-bin.chemical-bin .sort-bin-item { background: rgba(34, 197, 94, 0.3); color: var(--success); }
        .sort-bin.physical-bin .sort-bin-item { background: rgba(59, 130, 246, 0.3); color: var(--neutron); }
        .property-sort-score { text-align: center; font-size: 0.85rem; color: var(--text-secondary); }
        .property-sort-score span { color: var(--electron); font-weight: 700; }
        .isotope-compare-side-by-side { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-3); margin: var(--space-3) 0; }
        .isotope-compare-card { padding: var(--space-3); background: var(--glass-bg); border: 2px solid var(--glass-border); border-radius: 0.75rem; text-align: center; }
        .isotope-compare-card h4 { font-size: 1rem; margin-bottom: var(--space-2); }
        .isotope-compare-card .compare-symbol-big { font-size: 2.5rem; font-weight: 700; margin-bottom: var(--space-1); }
        .isotope-compare-card .compare-detail-list { list-style: none; text-align: left; font-size: 0.8rem; }
        .isotope-compare-card .compare-detail-list li { padding: 4px 0; border-bottom: 1px solid var(--glass-border); display: flex; justify-content: space-between; }
        .isotope-compare-card .compare-detail-list li:last-child { border-bottom: none; }
        .same-property { background: rgba(34, 197, 94, 0.1); border-left: 3px solid var(--success); padding-left: var(--space-1); }
        .diff-property { background: rgba(59, 130, 246, 0.1); border-left: 3px solid var(--neutron); padding-left: var(--space-1); }
        .confetti {
            position: absolute;
            width: 10px;
            height: 10px;
            animation: confettiFall 3s ease-out forwards;
        }

        @keyframes confettiFall {
            0% { transform: translateY(-100vh) rotate(0deg); opacity: 1; }
            100% { transform: translateY(100vh) rotate(720deg); opacity: 0; }
        }

        /* Points Toast */
        .points-toast {
            position: fixed;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            padding: var(--space-3) var(--space-5);
            background: var(--electron);
            color: #000;
            font-size: 2rem;
            font-weight: 700;
            border-radius: 1rem;
            z-index: 200;
            animation: pointsPopup 1s ease forwards;
        }

        @keyframes pointsPopup {
            0% { opacity: 0; transform: translate(-50%, -50%) scale(0.5); }
            30% { opacity: 1; transform: translate(-50%, -50%) scale(1.2); }
            100% { opacity: 0; transform: translate(-50%, -50%) translateY(-50px); }
        }

        .lesson-overview {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            padding: var(--space-4);
            z-index: 50;
        }

        .overview-badge {
            display: inline-block;
            background: rgba(234, 179, 8, 0.15);
            border: 1px solid var(--electron);
            color: var(--electron);
            padding: var(--space-1) var(--space-3);
            border-radius: 2rem;
            font-size: 0.75rem;
            font-weight: 600;
            text-transform: uppercase;
            letter-spacing: 0.05em;
            margin-bottom: var(--space-3);
        }

        .overview-title {
            font-size: 2.5rem;
            font-weight: 700;
            color: var(--text-primary);
            margin-bottom: var(--space-4);
            text-align: center;
        }

        .overview-points {
            max-width: 600px;
            width: 100%;
            margin-bottom: var(--space-5);
        }

        .overview-point {
            display: flex;
            align-items: center;
            gap: var(--space-3);
            padding: var(--space-3);
            background: var(--glass-bg);
            border: 1px solid var(--glass-border);
            border-radius: 1rem;
            margin-bottom: var(--space-2);
            transition: all 0.2s ease;
        }

        .overview-point:hover {
            background: rgba(255, 255, 255, 0.1);
            border-color: var(--electron);
        }

        .overview-icon {
            font-size: 1.5rem;
            flex-shrink: 0;
        }

        .overview-point span:last-child {
            color: var(--text-primary);
            font-size: 1rem;
        }

        .start-lesson-btn {
            padding: var(--space-3) var(--space-6);
            background: var(--success);
            border: none;
            border-radius: 0.75rem;
            color: #000;
            font-size: 1.125rem;
            font-weight: 700;
            cursor: pointer;
            transition: all 0.2s ease;
        }

        .start-lesson-btn:hover {
            background: #16a34a;
            transform: translateY(-2px);
            box-shadow: 0 8px 24px rgba(34, 197, 94, 0.3);
        }

        /* =====================================================
           GAMIFIED ACTIVITY TYPE STYLES
           10 new interactive activity component CSS classes
           ===================================================== */

        /* A) Click-to-Reveal (flip cards) */
        .click-reveal-container {
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-2);
            justify-content: center;
        }

        .click-reveal-card {
            width: 140px;
            height: 100px;
            perspective: 600px;
            cursor: pointer;
        }

        .click-reveal-card-inner {
            position: relative;
            width: 100%;
            height: 100%;
            transition: transform 0.6s;
            transform-style: preserve-3d;
        }

        .click-reveal-card.flipped .click-reveal-card-inner {
            transform: rotateY(180deg);
        }

        .click-reveal-front,
        .click-reveal-back {
            position: absolute;
            width: 100%;
            height: 100%;
            backface-visibility: hidden;
            display: flex;
            align-items: center;
            justify-content: center;
            border-radius: 0.75rem;
            font-size: 0.8rem;
            text-align: center;
            padding: var(--space-2);
        }

        .click-reveal-front {
            background: var(--glass-bg);
            border: 2px solid var(--glass-border);
        }

        .click-reveal-back {
            background: rgba(34, 197, 94, 0.15);
            border: 2px solid var(--success);
            transform: rotateY(180deg);
        }

        .click-reveal-card.correct .click-reveal-back {
            background: rgba(34, 197, 94, 0.2);
            border-color: var(--success);
        }

        .click-reveal-card.incorrect .click-reveal-back {
            background: rgba(239, 68, 68, 0.2);
            border-color: var(--error);
        }

        /* B) Drag & Drop (sortable items) */
        .drag-drop-container {
            display: flex;
            flex-direction: column;
            gap: var(--space-3);
        }

        .drag-drop-pool {
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-2);
            padding: var(--space-3);
            background: rgba(0, 0, 0, 0.2);
            border-radius: 0.75rem;
            min-height: 80px;
            justify-content: center;
        }

        .drag-item {
            padding: var(--space-2) var(--space-3);
            background: var(--glass-bg);
            border: 2px solid var(--glass-border);
            border-radius: 0.5rem;
            cursor: grab;
            font-weight: 600;
            transition: all 0.2s;
            user-select: none;
        }

        .drag-item:hover {
            border-color: var(--electron);
            transform: scale(1.05);
        }

        .drag-item.dragging {
            opacity: 0.4;
            transform: scale(0.95);
        }

        .drag-item.placed {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.15);
            cursor: default;
        }

        .drop-zone {
            min-height: 60px;
            padding: var(--space-2);
            border: 2px dashed rgba(255, 255, 255, 0.3);
            border-radius: 0.5rem;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: var(--space-2);
            flex-wrap: wrap;
            transition: all 0.2s;
        }

        .drop-zone.drag-over {
            border-color: var(--electron);
            background: rgba(234, 179, 8, 0.1);
        }

        .drop-zone.correct {
            border-style: solid;
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.1);
        }

        .drop-zone-label {
            font-size: 0.75rem;
            color: var(--text-secondary);
            text-align: center;
            margin-bottom: var(--space-1);
        }

        /* C) Hotspot (clickable diagram zones) */
        .hotspot-container {
            position: relative;
            display: inline-block;
            max-width: 100%;
        }

        .hotspot-zone {
            position: absolute;
            cursor: pointer;
            border: 2px solid transparent;
            border-radius: 0.5rem;
            transition: all 0.2s;
        }

        .hotspot-zone:hover {
            border-color: var(--electron);
            background: rgba(234, 179, 8, 0.2);
        }

        .hotspot-zone.correct {
            border-color: var(--success) !important;
            background: rgba(34, 197, 94, 0.3) !important;
        }

        .hotspot-zone.incorrect {
            border-color: var(--error) !important;
            background: rgba(239, 68, 68, 0.3) !important;
        }

        .hotspot-zone.disabled {
            pointer-events: none;
        }

        /* D) Fill-in-the-Blank (text inputs) */
        .fill-blank-container {
            display: flex;
            flex-direction: column;
            gap: var(--space-2);
        }

        .fill-blank-row {
            display: flex;
            align-items: center;
            gap: var(--space-2);
            flex-wrap: wrap;
        }

        .fill-blank-label {
            font-size: 0.85rem;
            min-width: 120px;
        }

        .fill-blank-input {
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.3);
            color: white;
            padding: 0.5rem 1rem;
            border-radius: 0.5rem;
            width: 120px;
            text-align: center;
            font-size: 0.9rem;
            transition: all 0.2s;
        }

        .fill-blank-input:focus {
            outline: none;
            border-color: var(--electron);
        }

        .fill-blank-input.correct {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.15);
            color: var(--success);
        }

        .fill-blank-input.incorrect {
            border-color: var(--error);
            background: rgba(239, 68, 68, 0.15);
            color: var(--error);
        }

        .fill-blank-feedback {
            font-size: 0.8rem;
            margin-left: var(--space-2);
        }

        /* E) Matching (connect pairs) */
        .matching-container {
            display: flex;
            gap: var(--space-4);
            justify-content: space-around;
        }

        .match-column {
            flex: 1;
            display: flex;
            flex-direction: column;
            gap: var(--space-2);
        }

        .match-label {
            font-size: 0.8rem;
            color: var(--text-secondary);
            text-align: center;
            margin-bottom: var(--space-1);
            font-weight: 700;
            text-transform: uppercase;
            letter-spacing: 1px;
        }

        .match-item {
            padding: var(--space-2);
            background: rgba(255, 255, 255, 0.1);
            border: 2px solid rgba(255, 255, 255, 0.2);
            border-radius: 0.5rem;
            cursor: grab;
            text-align: center;
            font-weight: 600;
            transition: all 0.2s;
        }

        .match-item:hover {
            border-color: var(--electron);
            transform: scale(1.03);
        }

        .match-item.selected {
            border-color: var(--electron);
            background: rgba(234, 179, 8, 0.2);
            box-shadow: 0 0 10px rgba(234, 179, 8, 0.3);
        }

        .match-item.matched {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.2);
            cursor: default;
        }

        .match-item.wrong {
            border-color: var(--error);
            animation: shake 0.3s ease;
        }

        /* F) True/False Toggle (switch buttons) */
        .toggle-container {
            display: flex;
            flex-direction: column;
            gap: var(--space-2);
        }

        .toggle-row {
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: var(--space-2);
            background: rgba(255, 255, 255, 0.03);
            border-radius: 0.5rem;
            gap: var(--space-2);
        }

        .toggle-statement {
            flex: 1;
            font-size: 0.85rem;
        }

        .toggle-switch {
            width: 60px;
            height: 30px;
            border-radius: 15px;
            cursor: pointer;
            transition: all 0.3s;
            display: flex;
            align-items: center;
            padding: 3px;
            flex-shrink: 0;
        }

        .toggle-switch.off {
            background: rgba(239, 68, 68, 0.4);
            justify-content: flex-start;
        }

        .toggle-switch.on {
            background: rgba(34, 197, 94, 0.4);
            justify-content: flex-end;
        }

        .toggle-knob {
            width: 24px;
            height: 24px;
            border-radius: 50%;
            background: white;
            transition: all 0.3s;
        }

        .toggle-switch.correct {
            border: 2px solid var(--success);
        }

        .toggle-switch.incorrect {
            border: 2px solid var(--error);
        }

        /* G) Sequencing (arrange in order) */
        .sequence-container {
            display: flex;
            flex-direction: column;
            gap: var(--space-3);
        }

        .sequence-pool {
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-2);
            padding: var(--space-3);
            background: rgba(0, 0, 0, 0.2);
            border-radius: 0.75rem;
            min-height: 80px;
            justify-content: center;
        }

        .sequence-item {
            padding: var(--space-2) var(--space-3);
            background: var(--glass-bg);
            border: 2px solid rgba(255, 255, 255, 0.2);
            border-radius: 0.5rem;
            cursor: grab;
            display: flex;
            align-items: center;
            gap: var(--space-2);
            transition: all 0.2s;
        }

        .sequence-item:hover {
            border-color: var(--electron);
            transform: scale(1.02);
        }

        .sequence-item.dragging {
            opacity: 0.4;
        }

        .sequence-item.correct {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.15);
        }

        .sequence-item.incorrect {
            border-color: var(--error);
            background: rgba(239, 68, 68, 0.15);
        }

        .seq-number {
            min-width: 28px;
            height: 28px;
            background: var(--electron);
            color: #000;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 0.8rem;
            flex-shrink: 0;
        }

        /* H) Highlight (click words to highlight) */
        .highlight-container {
            line-height: 1.8;
            font-size: 0.95rem;
        }

        .highlight-word {
            cursor: pointer;
            padding: 2px 4px;
            border-radius: 4px;
            transition: all 0.2s;
        }

        .highlight-word:hover {
            background: rgba(255, 255, 255, 0.1);
        }

        .highlight-word.selected {
            background: rgba(234, 179, 8, 0.25);
            border-bottom: 2px solid var(--electron);
        }

        .highlight-word.correct {
            background: rgba(34, 197, 94, 0.25);
            border-bottom: 2px solid var(--success);
        }

        .highlight-word.incorrect {
            background: rgba(239, 68, 68, 0.25);
            border-bottom: 2px solid var(--error);
        }

        /* I) Word Scramble (unscramble letters) */
        .scramble-container {
            display: flex;
            flex-direction: column;
            gap: var(--space-3);
            align-items: center;
        }

        .scramble-word-row {
            display: flex;
            gap: var(--space-2);
            align-items: center;
            flex-wrap: wrap;
            justify-content: center;
        }

        .scramble-letter {
            width: 44px;
            height: 44px;
            display: flex;
            align-items: center;
            justify-content: center;
            background: var(--glass-bg);
            border: 2px solid var(--glass-border);
            border-radius: 0.5rem;
            font-weight: 700;
            font-size: 1.1rem;
            cursor: grab;
            transition: all 0.2s;
            user-select: none;
        }

        .scramble-letter:hover {
            border-color: var(--electron);
            transform: scale(1.1);
        }

        .scramble-letter.selected {
            border-color: var(--electron);
            background: rgba(234, 179, 8, 0.2);
        }

        .scramble-letter.placed {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.15);
        }

        .scramble-slot {
            width: 44px;
            height: 44px;
            border: 2px dashed rgba(255, 255, 255, 0.3);
            border-radius: 0.5rem;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.1rem;
            transition: all 0.2s;
        }

        .scramble-slot.filled {
            border-style: solid;
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.1);
        }

        .scramble-slot.correct {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.2);
        }

        .scramble-slot.incorrect {
            border-color: var(--error);
            background: rgba(239, 68, 68, 0.2);
        }

        /* J) Interactive Diagram (label placement) */
        .diagram-label-container {
            position: relative;
            display: inline-block;
        }

        .diagram-label {
            position: absolute;
            cursor: pointer;
            padding: var(--space-1) var(--space-2);
            background: var(--glass-bg);
            border: 2px solid var(--glass-border);
            border-radius: 0.5rem;
            font-size: 0.8rem;
            font-weight: 600;
            transition: all 0.2s;
            white-space: nowrap;
        }

        .diagram-label:hover {
            border-color: var(--electron);
            background: rgba(234, 179, 8, 0.2);
        }

        .diagram-label.selected {
            border-color: var(--electron);
            background: rgba(234, 179, 8, 0.2);
        }

        .diagram-label.placed {
            border-color: var(--success);
            background: rgba(34, 197, 94, 0.2);
            cursor: default;
        }

        .diagram-label.incorrect {
            border-color: var(--error);
            background: rgba(239, 68, 68, 0.2);
        }

        .diagram-target-zone {
            position: absolute;
            cursor: pointer;
            border: 2px dashed rgba(255, 255, 255, 0.3);
            border-radius: 0.5rem;
            transition: all 0.2s;
        }

        .diagram-target-zone:hover {
            border-color: var(--electron);
            background: rgba(234, 179, 8, 0.1);
        }

        .diagram-target-zone.correct {
            border-color: var(--success);
            border-style: solid;
            background: rgba(34, 197, 94, 0.2);
        }

        .diagram-target-zone.incorrect {
            border-color: var(--error);
            border-style: solid;
            background: rgba(239, 68, 68, 0.2);
        }

        /* =====================================================
           SHARED FEEDBACK ANIMATIONS
           ===================================================== */

        @keyframes shake {
            0%, 100% { transform: translateX(0); }
            25% { transform: translateX(-5px); }
            75% { transform: translateX(5px); }
        }

        .feedback-correct {
            color: var(--success);
            font-weight: 600;
        }

        .feedback-incorrect {
            color: var(--error);
            font-weight: 600;
        }

        .feedback-partial {
            color: var(--electron);
            font-weight: 600;
        }

.race-hud { display: flex; gap: 1rem; margin-bottom: 1rem; font-weight: 600; flex-wrap: wrap; }
.race-hud > div { padding: 0.4rem 0.8rem; background: var(--glass-bg); border-radius: 8px; border: 1px solid var(--glass-border); }
.race-word { font-size: 2.5rem; font-weight: 800; letter-spacing: 0.3em; text-align: center; padding: 1.5rem; background: var(--glass-bg); border-radius: 12px; margin: 1rem 0; color: var(--text-primary); }
.race-input { font-size: 1.2rem; padding: 0.5rem 1rem; border-radius: 8px; border: 1px solid var(--glass-border); background: var(--glass-bg); color: var(--text-primary); width: 60%; }
.race-start, .race-input { display: block; margin: 0.5rem auto; }
.race-start { padding: 0.5rem 1.5rem; background: var(--success); color: white; border: none; border-radius: 8px; font-weight: 600; cursor: pointer; }
.race-feedback { text-align: center; min-height: 1.5em; margin-top: 0.5rem; }

.mb-builder { display: flex; flex-direction: column; gap: 1rem; }
.mb-palette { display: flex; gap: 0.5rem; justify-content: center; flex-wrap: wrap; }
.mb-add, .mb-sub, .mb-check, .mb-reset { padding: 0.5rem 1rem; border-radius: 8px; border: 1px solid var(--glass-border); background: var(--glass-bg); color: var(--text-primary); cursor: pointer; font-weight: 600; }
.mb-add[data-atom="C"] { background: var(--proton); color: white; }
.mb-add[data-atom="H"] { background: var(--neutron); color: white; }
.mb-canvas { position: relative; min-height: 200px; background: var(--glass-bg); border-radius: 12px; border: 1px solid var(--glass-border); }
.mb-atom { position: absolute; width: 40px; height: 40px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: 700; color: white; }
.mb-c { background: var(--proton); }
.mb-h { background: var(--neutron); }
.mb-formula { text-align: center; font-size: 1.5rem; font-weight: 700; }
.mb-feedback { text-align: center; min-height: 1.5em; }

.bp-jump-area { position: relative; min-height: 350px; background: var(--glass-bg); border-radius: 12px; border: 1px solid var(--glass-border); overflow: hidden; }
.bj-platform { position: absolute; width: 60px; height: 14px; background: var(--success); border-radius: 4px; color: white; font-size: 0.7rem; text-align: center; line-height: 14px; font-weight: 700; }
.bj-player { position: absolute; width: 30px; height: 30px; background: var(--electron); border-radius: 50%; transition: all 0.5s; bottom: 20px; left: 10%; box-shadow: 0 0 10px var(--electron); }
.bj-hud { display: flex; gap: 1rem; margin-bottom: 0.5rem; font-weight: 600; }
.bj-start { padding: 0.5rem 1.5rem; background: var(--success); color: white; border: none; border-radius: 8px; font-weight: 600; cursor: pointer; }

.eq-cutter-area { display: flex; flex-direction: column; gap: 1rem; padding: 1rem; }
.ec-equation { display: flex; flex-wrap: wrap; gap: 0.4rem; justify-content: center; font-size: 1.5rem; font-weight: 700; }
.ec-token { padding: 0.3rem 0.6rem; background: var(--glass-bg); border: 1px solid var(--glass-border); border-radius: 6px; cursor: pointer; }
.ec-token.ec-wrong { background: var(--error); color: white; }
.ec-token.cut { text-decoration: line-through; opacity: 0.4; }
.ec-slot { display: inline-block; padding: 0.3rem 0.8rem; margin: 0 0.2rem; background: var(--glass-bg); border: 2px dashed var(--glass-border); border-radius: 6px; cursor: pointer; }
.ec-slot.ec-slot-correct { background: var(--success); color: white; border-style: solid; }
.ec-rope { text-align: center; font-size: 1.2rem; min-height: 1.5em; }
.ec-feedback { text-align: center; min-height: 1.5em; }

.mg-clues { background: var(--glass-bg); padding: 1rem; border-radius: 8px; margin-bottom: 1rem; }
.mg-clue { padding: 0.3rem 0; }
.mg-options { display: grid; grid-template-columns: 1fr 1fr; gap: 0.5rem; }
.mg-option-btn { padding: 0.8rem; background: var(--glass-bg); border: 1px solid var(--glass-border); border-radius: 8px; color: var(--text-primary); cursor: pointer; font-weight: 600; }
.mg-option-btn:hover { background: var(--electron); color: white; }
.mg-option-btn.mg-correct { background: var(--success); color: white; }
.mg-option-btn.mg-wrong { background: var(--error); color: white; opacity: 0.5; }
.mg-feedback { text-align: center; min-height: 1.5em; margin-top: 0.5rem; }
.mg-score { font-weight: 700; }

.dg-scenario { background: var(--glass-bg); padding: 1rem; border-radius: 8px; margin-bottom: 1rem; font-style: italic; }
.dg-cases { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.5rem; }
.dg-case { aspect-ratio: 1; background: var(--neutron); color: white; border: none; border-radius: 12px; font-size: 1.5rem; font-weight: 800; cursor: pointer; transition: all 0.3s; }
.dg-case.dg-revealed { background: var(--text-secondary); }
.dg-offer { text-align: center; font-size: 1.2rem; font-weight: 700; margin: 1rem 0; color: var(--electron); }
.dg-deal, .dg-nodeal { padding: 0.5rem 1.5rem; border-radius: 8px; border: none; font-weight: 700; cursor: pointer; margin: 0 0.5rem; }
.dg-deal { background: var(--success); color: white; }
.dg-nodeal { background: var(--error); color: white; }
.dg-feedback { text-align: center; min-height: 1.5em; margin-top: 0.5rem; }

.fn-fruit { font-size: 1.4rem; padding: 1.5rem; background: var(--glass-bg); border-radius: 12px; text-align: center; min-height: 100px; display: flex; align-items: center; justify-content: center; transition: transform 0.2s; }
.fn-true, .fn-false { padding: 0.8rem 2rem; border-radius: 8px; border: none; font-weight: 700; cursor: pointer; margin: 0.5rem; font-size: 1.1rem; }
.fn-true { background: var(--success); color: white; }
.fn-false { background: var(--error); color: white; }
.fn-hud { display: flex; gap: 1rem; margin: 1rem 0; font-weight: 600; }
.fn-hud > div { padding: 0.4rem 0.8rem; background: var(--glass-bg); border-radius: 8px; }
.fn-feedback { text-align: center; min-height: 1.5em; }

.sg-pads { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.8rem; padding: 1rem; }
.sg-pad { padding: 2rem 1rem; border-radius: 12px; color: white; text-align: center; font-weight: 700; cursor: pointer; opacity: 0.6; transition: all 0.3s; border: 2px solid var(--glass-border); }
.sg-hud { display: flex; gap: 1rem; margin-bottom: 1rem; font-weight: 600; }
.sg-hud > div { padding: 0.4rem 0.8rem; background: var(--glass-bg); border-radius: 8px; }
.sg-start { padding: 0.5rem 1.5rem; background: var(--success); color: white; border: none; border-radius: 8px; font-weight: 600; cursor: pointer; }
.sg-status { text-align: center; min-height: 1.5em; font-weight: 600; }

.ts-card { padding: 2rem 1rem; background: var(--glass-bg); border: 2px solid var(--glass-border); border-radius: 16px; text-align: center; font-size: 1.2rem; min-height: 120px; display: flex; align-items: center; justify-content: center; margin-bottom: 1rem; }
.ts-accept, .ts-reject { padding: 0.8rem 2rem; border-radius: 8px; border: none; font-weight: 700; cursor: pointer; margin: 0 0.5rem; font-size: 1.1rem; }
.ts-accept { background: var(--success); color: white; }
.ts-reject { background: var(--error); color: white; }
.ts-hud { display: flex; gap: 1rem; margin-bottom: 1rem; font-weight: 600; }
.ts-feedback { text-align: center; min-height: 1.5em; }

.ab-arena { position: relative; min-height: 250px; background: var(--glass-bg); border-radius: 12px; border: 1px solid var(--glass-border); padding: 1rem; }
.ab-bird { position: absolute; bottom: 20px; left: 10%; width: 40px; height: 40px; background: var(--proton); border-radius: 50%; transition: all 1s; }
.ab-target { position: absolute; bottom: 20px; right: 5%; width: 60px; height: 60px; background: var(--electron); border-radius: 8px; }
.ab-controls { display: flex; flex-wrap: wrap; gap: 1rem; align-items: center; margin-top: 1rem; }
.ab-controls label { display: flex; flex-direction: column; gap: 0.2rem; font-weight: 600; }
.ab-launch { padding: 0.5rem 1.5rem; background: var(--success); color: white; border: none; border-radius: 8px; font-weight: 600; cursor: pointer; }
.ab-result { text-align: center; min-height: 1.5em; margin-top: 1rem; font-weight: 600; }

.vd-cards { display: flex; flex-wrap: wrap; gap: 0.5rem; padding: 1rem; min-height: 80px; background: var(--glass-bg); border-radius: 8px; margin-bottom: 1rem; }
.vd-card { padding: 0.6rem 1rem; background: var(--electron); color: white; border-radius: 8px; cursor: grab; font-weight: 600; }
.vd-zones { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 0.5rem; }
.vd-zone { min-height: 150px; padding: 1rem; background: var(--glass-bg); border: 2px dashed var(--glass-border); border-radius: 12px; }
.vd-zone.vd-correct { border-color: var(--success); background: rgba(34, 197, 94, 0.1); }
.vd-zone-label { text-align: center; font-weight: 700; margin-bottom: 0.5rem; }
.vd-feedback { text-align: center; min-height: 1.5em; margin-top: 0.5rem; }
.vd-score { font-weight: 700; }

.bb-arena { display: flex; flex-direction: column; gap: 1rem; }
.bb-boss { padding: 1rem; background: var(--glass-bg); border-radius: 12px; text-align: center; }
.bb-hp { font-size: 1.2rem; font-weight: 700; }
.bb-attack { color: var(--text-secondary); }
.bb-hand { display: grid; grid-template-columns: repeat(4, 1fr); gap: 0.5rem; }
.bb-card { padding: 1rem 0.5rem; background: var(--glass-bg); border: 2px solid var(--glass-border); border-radius: 8px; cursor: pointer; color: var(--text-primary); text-align: center; transition: all 0.2s; }
.bb-card:hover { background: var(--proton); color: white; transform: translateY(-4px); }
.bb-card-marks { font-size: 1.2rem; font-weight: 800; color: var(--electron); }
.bb-card-text { font-size: 0.85rem; margin-top: 0.4rem; }
.bb-log { text-align: center; min-height: 1.5em; font-weight: 600; }
.bb-reset { padding: 0.5rem 1.5rem; background: var(--text-secondary); color: white; border: none; border-radius: 8px; font-weight: 600; cursor: pointer; }

/* === PLAN_V3 GAME STYLES (slides 01-05) === */

/* -----------------------------------------------
   HANGMAN
   ----------------------------------------------- */

.hangman-container {
    display: grid;
    grid-template-columns: 220px 1fr 260px;
    gap: 20px;
    padding: 16px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    min-height: 480px;
}

.hangman-left {
    display: flex;
    flex-direction: column;
    gap: 14px;
    align-items: center;
    padding: 10px 8px;
}

.hangman-center {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
    padding: 10px 0;
}

.hangman-right {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 14px;
    padding: 10px 8px;
}

.hangman-lives {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--error);
    text-align: center;
}

.hangman-lives-count {
    font-size: 2rem;
    font-weight: 800;
}

.hangman-picker-label {
    font-size: 0.72rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.hangman-picker {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
    justify-content: center;
}

.hangman-picker-btn {
    width: 38px;
    height: 38px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--glass-bg);
    border: 2px solid rgba(255, 255, 255, 0.15);
    border-radius: 10px;
    color: var(--text-primary);
    font-weight: 700;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s;
}

.hangman-picker-btn:hover {
    border-color: var(--electron);
    transform: scale(1.1);
}

.hangman-picker-btn:focus {
    outline: none;
    border-color: var(--electron);
    box-shadow: 0 0 0 2px rgba(234, 179, 8, 0.3);
}

.hangman-picker-btn.active {
    background: rgba(234, 179, 8, 0.25);
    border-color: var(--electron);
    color: var(--electron);
    box-shadow: 0 0 12px rgba(234, 179, 8, 0.3);
}

.hangman-mode-row {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    justify-content: center;
}

.hangman-mode-btn {
    padding: 7px 12px;
    background: rgba(234, 179, 8, 0.12);
    border: 1px solid var(--electron);
    border-radius: 20px;
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--electron);
    cursor: pointer;
    transition: all 0.2s;
    white-space: nowrap;
}

.hangman-mode-btn:hover {
    background: rgba(234, 179, 8, 0.3);
    transform: scale(1.05);
}

.hangman-mode-btn:focus {
    outline: none;
    box-shadow: 0 0 0 2px rgba(234, 179, 8, 0.3);
}

.hangman-word {
    display: flex;
    gap: 10px;
    justify-content: center;
    flex-wrap: wrap;
    margin: 8px 0;
    min-height: 80px;
    align-items: center;
}

.hangman-letter-cell {
    width: 52px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-bottom: 3px solid var(--electron);
    font-size: 2.2rem;
    font-weight: 800;
    color: transparent;
    transition: all 0.3s;
    background: rgba(255, 255, 255, 0.03);
    border-radius: 6px 6px 0 0;
}

.hangman-letter-cell.revealed {
    color: var(--success);
    border-bottom-color: var(--success);
    background: rgba(34, 197, 94, 0.08);
}

.hangman-message {
    font-size: 0.95rem;
    font-weight: 700;
    text-align: center;
    min-height: 1.5em;
    color: var(--text-primary);
}

.hangman-keyboard {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 6px;
    max-width: 520px;
    padding: 8px;
}

.hangman-key {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--glass-bg);
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    color: var(--text-primary);
    font-weight: 700;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.2s;
}

.hangman-key:hover {
    border-color: var(--electron);
    transform: scale(1.08);
}

.hangman-key:active {
    transform: scale(0.95);
}

.hangman-key:focus {
    outline: none;
    border-color: var(--electron);
    box-shadow: 0 0 0 2px rgba(234, 179, 8, 0.3);
}

.hangman-key.correct {
    border-color: var(--success);
    background: rgba(34, 197, 94, 0.15);
    color: var(--success);
}

.hangman-key.incorrect {
    border-color: var(--error);
    background: rgba(239, 68, 68, 0.15);
    color: var(--error);
}

.hangman-key.used {
    opacity: 0.3;
    pointer-events: none;
}

.hangman-gallows {
    position: relative;
    width: 200px;
    height: 180px;
    border-bottom: 3px solid var(--text-secondary);
    border-left: 3px solid var(--text-secondary);
}

.hangman-gallows::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100px;
    height: 3px;
    background: var(--text-secondary);
}

.hangman-gallows::after {
    content: '';
    position: absolute;
    top: 0;
    left: 100px;
    width: 3px;
    height: 30px;
    background: var(--text-secondary);
}

.hangman-part {
    position: absolute;
    display: none;
}

.hangman-part-head {
    width: 24px;
    height: 24px;
    border: 3px solid var(--error);
    border-radius: 50%;
    top: 30px;
    left: 88px;
}

.hangman-part-body {
    width: 3px;
    height: 40px;
    background: var(--error);
    top: 54px;
    left: 99px;
}

.hangman-part-left-arm {
    width: 26px;
    height: 3px;
    background: var(--error);
    top: 62px;
    left: 74px;
    transform-origin: right center;
    transform: rotate(-30deg);
}

.hangman-part-right-arm {
    width: 26px;
    height: 3px;
    background: var(--error);
    top: 62px;
    left: 100px;
    transform-origin: left center;
    transform: rotate(30deg);
}

.hangman-part-left-leg {
    width: 26px;
    height: 3px;
    background: var(--error);
    top: 94px;
    left: 74px;
    transform-origin: right center;
    transform: rotate(-30deg);
}

.hangman-part-right-leg {
    width: 26px;
    height: 3px;
    background: var(--error);
    top: 94px;
    left: 100px;
    transform-origin: left center;
    transform: rotate(30deg);
}

.hangman-feedback {
    font-size: 0.9rem;
    font-weight: 700;
    text-align: center;
    min-height: 1.5em;
    color: var(--text-secondary);
    padding: 6px 12px;
    border-radius: 8px;
}

.hangman-feedback.correct {
    color: var(--success);
    background: rgba(34, 197, 94, 0.1);
}

.hangman-feedback.incorrect {
    color: var(--error);
    background: rgba(239, 68, 68, 0.1);
}

/* -----------------------------------------------
   FLAPPY BIRD
   ----------------------------------------------- */

.flappy-container {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    padding: var(--space-2);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
}

.flappy-stage {
    position: relative;
    width: 100%;
    height: 220px;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--glass-border);
}

.flappy-character {
    position: absolute;
    left: 15%;
    width: 40px;
    height: 40px;
    background: var(--electron);
    border-radius: 50% 50% 50% 30%;
    transition: top 0.4s ease;
    z-index: 2;
}

.flappy-character::before {
    content: '';
    position: absolute;
    top: 8px;
    right: -4px;
    width: 12px;
    height: 8px;
    background: var(--error);
    border-radius: 0 8px 8px 0;
}

.flappy-character::after {
    content: '';
    position: absolute;
    top: 12px;
    right: 4px;
    width: 4px;
    height: 4px;
    background: var(--bg-dark);
    border-radius: 50%;
}

@keyframes flap {
    0%, 100% { transform: rotate(0deg); }
    50% { transform: rotate(-15deg); }
}

.flappy-zone {
    position: absolute;
    right: 10%;
    width: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    padding: 0.5rem;
    font-size: 0.8rem;
    font-weight: 700;
    text-align: center;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.2s;
    z-index: 1;
}

.flappy-zone:hover {
    border-color: var(--electron);
    transform: scale(1.03);
}

.flappy-zone:active {
    transform: scale(0.97);
}

.flappy-zone:focus {
    outline: none;
    border-color: var(--electron);
    box-shadow: 0 0 0 2px rgba(234, 179, 8, 0.3);
}

.flappy-zone.correct {
    border-color: var(--success);
    background: rgba(34, 197, 94, 0.15);
    color: var(--success);
}

.flappy-zone.incorrect {
    border-color: var(--error);
    background: rgba(239, 68, 68, 0.15);
    color: var(--error);
}

.flappy-question {
    position: absolute;
    left: 50%;
    top: 10px;
    transform: translateX(-50%);
    padding: 0.4rem 1rem;
    background: rgba(0, 0, 0, 0.7);
    border-radius: 8px;
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-primary);
    z-index: 3;
    text-align: center;
    max-width: 80%;
}

.flappy-score,
.flappy-lives,
.flappy-streak {
    font-size: 0.85rem;
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.flappy-score { color: var(--electron); }
.flappy-lives { color: var(--error); }
.flappy-streak { color: var(--neutron); }

.flappy-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 0.3rem 0.8rem;
    background: rgba(234, 179, 8, 0.15);
    border: 1px solid var(--electron);
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--electron);
}

.flappy-timer {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.flappy-flash {
    position: absolute;
    inset: 0;
    border-radius: 8px;
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.3s;
    z-index: 5;
}

.flappy-flash.flash-success {
    background: rgba(34, 197, 94, 0.2);
    opacity: 1;
}

.flappy-flash.flash-error {
    background: rgba(239, 68, 68, 0.2);
    opacity: 1;
}

/* -----------------------------------------------
   BINGO
   ----------------------------------------------- */

.bingo-container {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    padding: var(--space-2);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
}

.bingo-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 6px;
    max-width: 360px;
    margin: 0 auto;
}

.bingo-cell {
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.05);
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.2s;
    user-select: none;
}

.bingo-cell:hover {
    border-color: var(--electron);
    transform: scale(1.05);
}

.bingo-cell:active {
    transform: scale(0.95);
}

.bingo-cell:focus {
    outline: none;
    border-color: var(--electron);
    box-shadow: 0 0 0 2px rgba(234, 179, 8, 0.3);
}

.bingo-cell.matched {
    border-color: var(--success);
    background: rgba(34, 197, 94, 0.2);
    color: var(--success);
}

.bingo-cell.wrong {
    border-color: var(--error);
    background: rgba(239, 68, 68, 0.15);
    color: var(--error);
    animation: shake 0.4s ease;
}

.bingo-cell.bingo-line {
    border-color: var(--electron);
    background: rgba(234, 179, 8, 0.25);
    color: var(--electron);
    box-shadow: 0 0 12px rgba(234, 179, 8, 0.3);
}

.bingo-caller {
    text-align: center;
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
}

.bingo-call-display {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-1);
    padding: var(--space-1);
    background: rgba(0, 0, 0, 0.3);
    border-radius: 8px;
    font-size: 1.3rem;
    font-weight: 800;
    color: var(--electron);
    min-height: 52px;
}

.bingo-next-btn {
    padding: 0.5rem 1.5rem;
    background: var(--electron);
    color: var(--bg-dark);
    border: none;
    border-radius: 8px;
    font-weight: 700;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.2s;
    align-self: center;
}

.bingo-next-btn:hover {
    transform: scale(1.04);
    box-shadow: 0 0 12px rgba(234, 179, 8, 0.4);
}

.bingo-next-btn:active {
    transform: scale(0.97);
}

.bingo-next-btn:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(234, 179, 8, 0.3);
}

.bingo-streak {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--neutron);
    text-align: center;
}

.bingo-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 0.3rem 0.8rem;
    background: rgba(234, 179, 8, 0.15);
    border: 1px solid var(--electron);
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--electron);
}

.bingo-timer {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-align: center;
}

/* -----------------------------------------------
   TOWER STACK
   ----------------------------------------------- */

.tower-container {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    padding: var(--space-2);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
}

.tower-stage {
    position: relative;
    width: 100%;
    min-height: 200px;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 8px;
    border: 1px solid var(--glass-border);
    display: flex;
    flex-direction: column-reverse;
    align-items: center;
    padding: var(--space-2);
    gap: 4px;
}

.tower-slots {
    display: flex;
    flex-direction: column-reverse;
    align-items: center;
    gap: 4px;
    width: 100%;
}

.tower-slot {
    width: 80%;
    max-width: 280px;
    height: 36px;
    border: 2px dashed rgba(255, 255, 255, 0.15);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
    transition: all 0.3s;
}

.tower-slot.filled {
    border-style: solid;
    border-color: rgba(255, 255, 255, 0.3);
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-primary);
}

.tower-slot.correct {
    border-color: var(--success);
    background: rgba(34, 197, 94, 0.15);
    color: var(--success);
}

.tower-slot.incorrect {
    border-color: var(--error);
    background: rgba(239, 68, 68, 0.15);
    color: var(--error);
    animation: shake 0.4s ease;
}

.tower-conveyor {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-1);
    padding: var(--space-1);
    background: rgba(0, 0, 0, 0.2);
    border-radius: 8px;
    min-height: 48px;
}

.tower-item {
    padding: 0.4rem 0.8rem;
    background: var(--glass-bg);
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: 8px;
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.2s;
    user-select: none;
}

.tower-item:hover {
    border-color: var(--electron);
    transform: scale(1.06);
}

.tower-item:active {
    transform: scale(0.95);
}

.tower-item:focus {
    outline: none;
    border-color: var(--electron);
    box-shadow: 0 0 0 2px rgba(234, 179, 8, 0.3);
}

.tower-item.selected {
    border-color: var(--electron);
    background: rgba(234, 179, 8, 0.15);
    color: var(--electron);
}

.tower-item.used {
    opacity: 0.3;
    pointer-events: none;
}

.tower-question-card {
    padding: var(--space-1) var(--space-2);
    background: rgba(0, 0, 0, 0.5);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 600;
    text-align: center;
    color: var(--text-primary);
}

.tower-lives {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--error);
    text-align: center;
}

.tower-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 0.3rem 0.8rem;
    background: rgba(234, 179, 8, 0.15);
    border: 1px solid var(--electron);
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--electron);
    text-align: center;
}

.tower-message {
    font-size: 0.95rem;
    font-weight: 700;
    text-align: center;
    min-height: 1.5em;
    color: var(--text-primary);
}

/* -----------------------------------------------
   CRUDE DETECTIVE: CLUE & LOCATE
   Wide-layout design for the slide-local standalone view.
   ----------------------------------------------- */

        /* Break the activity panel out of the 800px cap so the detective game
           can use the full LHS width (60% of the viewport). */
.detective-container {
            --detective-amber: #fbbf24;
            --detective-amber-soft: rgba(251, 191, 36, 0.18);
            --detective-paper: #1f1a0e;
            --detective-paper-line: rgba(251, 191, 36, 0.08);
            --detective-shadow: 0 14px 32px rgba(0, 0, 0, 0.5);
            position: relative;
            display: flex;
            flex-direction: column;
            gap: 18px;
            padding: 24px;
            background:
                radial-gradient(1200px 280px at 0% 0%, rgba(251, 191, 36, 0.12), transparent 60%),
                radial-gradient(800px 220px at 100% 100%, rgba(59, 130, 246, 0.10), transparent 60%),
                linear-gradient(180deg, rgba(2, 6, 23, 0.85), rgba(2, 6, 23, 0.6));
            border: 1px solid rgba(251, 191, 36, 0.30);
            border-radius: 18px;
            box-shadow: var(--detective-shadow);
            overflow: hidden;
        }

        .detective-container::before {
            content: "";
            position: absolute;
            inset: 0;
            background-image:
                repeating-linear-gradient(0deg, transparent 0 32px, var(--detective-paper-line) 32px 33px);
            pointer-events: none;
            opacity: 0.55;
        }

        /* ----- Header ----- */
        .detective-header {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 16px;
            flex-wrap: wrap;
            padding-bottom: 14px;
            border-bottom: 1px dashed rgba(251, 191, 36, 0.30);
            position: relative;
            z-index: 1;
        }

        .detective-header-left {
            display: flex;
            align-items: center;
            gap: 16px;
        }

        .detective-magnifier {
            width: 56px;
            height: 56px;
            display: flex;
            align-items: center;
            justify-content: center;
            background: linear-gradient(135deg, rgba(251, 191, 36, 0.20), rgba(251, 191, 36, 0.05));
            border: 1.5px solid rgba(251, 191, 36, 0.50);
            border-radius: 50%;
            color: var(--detective-amber);
            box-shadow: 0 0 22px rgba(251, 191, 36, 0.30);
            animation: detective-magnifier-sway 4s ease-in-out infinite;
            flex-shrink: 0;
        }

        @keyframes detective-magnifier-sway {
            0%, 100% { transform: rotate(-6deg); }
            50% { transform: rotate(6deg); }
        }

        .detective-case-label {
            font-size: 0.72rem;
            font-weight: 800;
            letter-spacing: 2.5px;
            text-transform: uppercase;
            color: var(--detective-amber);
            opacity: 0.9;
        }

        .detective-case-title {
            font-family: 'Space Grotesk', system-ui, sans-serif;
            font-size: 1.4rem;
            font-weight: 800;
            color: var(--text-primary);
            letter-spacing: -0.01em;
            margin-top: 2px;
        }

        /* ----- Progress dots ----- */
        .detective-progress {
            display: flex;
            gap: 8px;
            align-items: center;
            padding: 8px 14px;
            background: rgba(0, 0, 0, 0.40);
            border: 1px solid rgba(251, 191, 36, 0.25);
            border-radius: 999px;
        }

        .detective-progress-dot {
            width: 12px;
            height: 12px;
            border-radius: 50%;
            background: rgba(255, 255, 255, 0.12);
            border: 1px solid rgba(255, 255, 255, 0.20);
            transition: all 0.3s ease;
        }

        .detective-progress-dot.active {
            background: var(--detective-amber);
            border-color: var(--detective-amber);
            box-shadow: 0 0 10px rgba(251, 191, 36, 0.8);
            transform: scale(1.2);
        }

        .detective-progress-dot.complete-correct {
            background: var(--success);
            border-color: var(--success);
            box-shadow: 0 0 8px rgba(34, 197, 94, 0.6);
        }

        .detective-progress-dot.complete-incorrect {
            background: var(--error);
            border-color: var(--error);
            box-shadow: 0 0 8px rgba(239, 68, 68, 0.6);
        }

        /* ----- Stats row ----- */
        .detective-stats {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 12px;
            position: relative;
            z-index: 1;
        }

        .detective-stat {
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 14px 16px;
            background: linear-gradient(180deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.01));
            border: 1px solid rgba(255, 255, 255, 0.10);
            border-left-width: 4px;
            border-radius: 12px;
            transition: transform 0.2s ease, border-color 0.2s ease;
        }

        .detective-stat-lives    { border-left-color: var(--proton); }
        .detective-stat-streak   { border-left-color: var(--electron); }
        .detective-stat-score    { border-left-color: var(--success); }
        .detective-stat-timer    { border-left-color: var(--neutron); }
        .detective-stat-timer.detective-stat-warning {
            border-color: var(--proton);
            border-left-color: var(--proton);
            animation: detective-stat-pulse 0.7s ease-in-out infinite;
        }

        @keyframes detective-stat-pulse {
            0%, 100% { background: linear-gradient(180deg, rgba(239, 68, 68, 0.10), rgba(239, 68, 68, 0.02)); }
            50% { background: linear-gradient(180deg, rgba(239, 68, 68, 0.28), rgba(239, 68, 68, 0.08)); }
        }

        .detective-stat-icon {
            font-size: 1.4rem;
            line-height: 1;
        }

        .detective-stat-info {
            display: flex;
            flex-direction: column;
            line-height: 1.15;
        }

        .detective-stat-label {
            font-size: 0.65rem;
            text-transform: uppercase;
            letter-spacing: 0.8px;
            color: var(--text-secondary);
            font-weight: 700;
        }

        .detective-stat-value {
            font-size: 1.25rem;
            font-weight: 800;
            color: var(--text-primary);
            font-variant-numeric: tabular-nums;
            margin-top: 1px;
        }

        .detective-stat-lives  .detective-stat-value { color: var(--proton); }
        .detective-stat-streak .detective-stat-value { color: var(--electron); }
        .detective-stat-score  .detective-stat-value { color: var(--success); }
        .detective-stat-timer  .detective-stat-value { color: var(--neutron); }
        .detective-stat-timer.detective-stat-warning .detective-stat-value { color: var(--proton); }

        /* ----- Clue card ----- */
        .detective-clue {
            position: relative;
            padding: 30px 26px 22px;
            background:
                linear-gradient(180deg, rgba(251, 191, 36, 0.08), rgba(251, 191, 36, 0.02)),
                repeating-linear-gradient(0deg, transparent 0 26px, rgba(251, 191, 36, 0.07) 26px 27px),
                linear-gradient(180deg, #1c1808, #15110a);
            border: 1.5px solid rgba(251, 191, 36, 0.40);
            border-radius: 14px;
            box-shadow:
                inset 0 0 0 1px rgba(0, 0, 0, 0.4),
                0 10px 26px rgba(0, 0, 0, 0.4);
            overflow: hidden;
            z-index: 1;
            animation: detective-clue-slide-in 0.45s cubic-bezier(0.18, 0.89, 0.32, 1.28);
        }

        @keyframes detective-clue-slide-in {
            0%   { opacity: 0; transform: translateY(-10px) scale(0.98); }
            100% { opacity: 1; transform: translateY(0) scale(1); }
        }

        .detective-clue-corner {
            position: absolute;
            width: 22px;
            height: 22px;
            border: 2.5px solid rgba(251, 191, 36, 0.65);
        }
        .detective-clue-corner-tl { top: 8px; left: 8px; border-right: 0; border-bottom: 0; }
        .detective-clue-corner-br { bottom: 8px; right: 8px; border-left: 0; border-top: 0; }

        .detective-clue-pin {
            position: absolute;
            top: 14px;
            right: 18px;
            width: 22px;
            height: 22px;
            pointer-events: none;
        }
        .detective-clue-pin-head {
            position: absolute;
            inset: 0;
            background: radial-gradient(circle at 35% 35%, #fca5a5, #b91c1c 60%, #7f1d1d);
            border-radius: 50%;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.55), inset 0 -2px 3px rgba(0, 0, 0, 0.3);
        }
        .detective-clue-pin-shine {
            position: absolute;
            top: 3px;
            left: 4px;
            width: 6px;
            height: 5px;
            background: rgba(255, 255, 255, 0.85);
            border-radius: 50%;
        }

        .detective-clue-eyebrow {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            font-size: 0.78rem;
            font-weight: 800;
            letter-spacing: 2.5px;
            text-transform: uppercase;
            color: var(--detective-amber);
            padding: 4px 10px;
            background: rgba(251, 191, 36, 0.10);
            border: 1px solid rgba(251, 191, 36, 0.40);
            border-radius: 5px;
            margin-bottom: 14px;
        }

        .detective-clue-eyebrow-icon { font-size: 0.95rem; }

        .detective-clue-text {
            font-size: 1.08rem;
            line-height: 1.6;
            color: #fef3c7;
            font-weight: 500;
            text-shadow: 0 1px 0 rgba(0, 0, 0, 0.4);
        }

        .detective-clue-footer {
            margin-top: 14px;
            padding-top: 10px;
            border-top: 1px dashed rgba(251, 191, 36, 0.22);
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .detective-clue-counter {
            font-size: 0.78rem;
            font-weight: 700;
            color: var(--detective-amber);
            letter-spacing: 0.6px;
            font-variant-numeric: tabular-nums;
            opacity: 0.9;
        }

        /* ----- Region (suspect) cards ----- */
        .detective-options {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 14px;
            position: relative;
            z-index: 1;
        }

        .detective-option {
            --opt-accent: rgba(255, 255, 255, 0.4);
            --opt-accent-soft: rgba(255, 255, 255, 0.06);
            position: relative;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            gap: 8px;
            padding: 22px 14px 18px;
            min-height: 150px;
            background: linear-gradient(180deg, rgba(255, 255, 255, 0.06), rgba(255, 255, 255, 0.02));
            border: 1.5px solid var(--opt-accent);
            border-radius: 14px;
            color: var(--text-primary);
            font-family: inherit;
            cursor: pointer;
            text-align: center;
            transition: transform 0.18s ease, border-color 0.2s ease, background 0.2s ease, box-shadow 0.2s ease;
            overflow: hidden;
            animation: detective-option-in 0.4s cubic-bezier(0.18, 0.89, 0.32, 1.28) backwards;
        }

        .detective-option:nth-child(1) { animation-delay: 0.05s; }
        .detective-option:nth-child(2) { animation-delay: 0.12s; }
        .detective-option:nth-child(3) { animation-delay: 0.19s; }
        .detective-option:nth-child(4) { animation-delay: 0.26s; }

        @keyframes detective-option-in {
            0%   { opacity: 0; transform: translateY(10px) scale(0.96); }
            100% { opacity: 1; transform: translateY(0) scale(1); }
        }

        .detective-option::before {
            content: "";
            position: absolute;
            inset: 0;
            background: linear-gradient(180deg, var(--opt-accent-soft), transparent 60%);
            opacity: 0;
            transition: opacity 0.2s ease;
            pointer-events: none;
        }

        .detective-option:hover:not(:disabled) {
            transform: translateY(-4px);
            box-shadow: 0 10px 22px rgba(0, 0, 0, 0.45), 0 0 0 3px var(--opt-accent-soft);
        }
        .detective-option:hover:not(:disabled)::before { opacity: 1; }

        .detective-option:active:not(:disabled) {
            transform: translateY(-1px) scale(0.98);
        }

        .detective-option:focus-visible {
            outline: none;
            box-shadow: 0 0 0 3px var(--opt-accent-soft);
        }

        .detective-option:disabled { cursor: not-allowed; }

        .detective-option-icon {
            font-size: 2rem;
            line-height: 1;
            margin-bottom: 2px;
            filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.4));
        }

        .detective-option-label {
            font-size: 0.95rem;
            font-weight: 800;
            letter-spacing: 0.2px;
        }

        .detective-option-sub {
            font-size: 0.7rem;
            font-weight: 600;
            text-transform: uppercase;
            letter-spacing: 1.2px;
            color: var(--text-secondary);
        }

        /* Region-specific accent colors */
        .detective-option[data-region-id="north-sea"]   { --opt-accent: #38bdf8; --opt-accent-soft: rgba(56, 189, 248, 0.20); }
        .detective-option[data-region-id="middle-east"] { --opt-accent: #fbbf24; --opt-accent-soft: rgba(251, 191, 36, 0.20); }
        .detective-option[data-region-id="texas"]       { --opt-accent: #f87171; --opt-accent-soft: rgba(248, 113, 113, 0.20); }
        .detective-option[data-region-id="alaska"]      { --opt-accent: #a5b4fc; --opt-accent-soft: rgba(165, 180, 252, 0.20); }

        /* Correct / incorrect states (override accent) */
        .detective-option-correct {
            border-color: var(--success) !important;
            background: linear-gradient(180deg, rgba(34, 197, 94, 0.40), rgba(34, 197, 94, 0.12)) !important;
            color: #ecfdf5;
            box-shadow: 0 0 0 3px rgba(34, 197, 94, 0.30), 0 0 28px rgba(34, 197, 94, 0.40);
            animation: detective-option-correct 0.6s ease;
        }
        @keyframes detective-option-correct {
            0%   { transform: scale(1); }
            35%  { transform: scale(1.08); }
            70%  { transform: scale(0.97); }
            100% { transform: scale(1); }
        }

        .detective-option-incorrect {
            border-color: var(--error) !important;
            background: linear-gradient(180deg, rgba(239, 68, 68, 0.32), rgba(239, 68, 68, 0.10)) !important;
            color: #fef2f2;
            box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.30);
            animation: detective-shake 0.45s ease;
        }
        @keyframes detective-shake {
            0%, 100% { transform: translateX(0); }
            20% { transform: translateX(-6px); }
            40% { transform: translateX(6px); }
            60% { transform: translateX(-4px); }
            80% { transform: translateX(4px); }
        }

        .detective-option-faded {
            opacity: 0.32;
            filter: grayscale(0.5);
        }

        /* ----- Footer ----- */
        .detective-footer {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 12px;
            position: relative;
            z-index: 1;
            margin-top: 4px;
        }

        .detective-start {
            --stamp-shadow: 0 5px 0 #92400e, 0 10px 24px rgba(251, 191, 36, 0.40);
            position: relative;
            display: inline-flex;
            align-items: center;
            gap: 10px;
            padding: 14px 30px;
            background: linear-gradient(180deg, #fcd34d, #f59e0b);
            color: #422006;
            border: 2.5px solid #b45309;
            border-radius: 12px;
            font-family: inherit;
            font-weight: 800;
            font-size: 1.05rem;
            letter-spacing: 0.8px;
            text-transform: uppercase;
            cursor: pointer;
            box-shadow: var(--stamp-shadow);
            transition: transform 0.15s ease, box-shadow 0.15s ease;
        }

        .detective-start:hover {
            transform: translateY(-2px);
            box-shadow: 0 7px 0 #92400e, 0 14px 28px rgba(251, 191, 36, 0.50);
        }

        .detective-start:active {
            transform: translateY(3px);
            box-shadow: 0 2px 0 #92400e, 0 4px 10px rgba(251, 191, 36, 0.3);
        }

        .detective-start:focus-visible {
            outline: none;
            box-shadow: 0 5px 0 #92400e, 0 10px 24px rgba(251, 191, 36, 0.40), 0 0 0 4px rgba(251, 191, 36, 0.35);
        }

        .detective-start-icon { font-size: 1.15rem; }

        .detective-start[disabled] {
            opacity: 0.5;
            cursor: not-allowed;
            transform: none;
            box-shadow: 0 5px 0 #92400e, 0 4px 8px rgba(0, 0, 0, 0.2);
        }

        .detective-status {
            min-height: 32px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 0.9rem;
            font-weight: 600;
            color: var(--text-secondary);
            text-align: center;
            letter-spacing: 0.2px;
        }

        .detective-status.detective-badge-active {
            display: inline-flex;
            align-items: center;
            gap: 10px;
            padding: 8px 18px;
            background: linear-gradient(135deg, rgba(251, 191, 36, 0.28), rgba(251, 191, 36, 0.10));
            border: 1.5px solid var(--detective-amber);
            border-radius: 999px;
            font-size: 0.85rem;
            font-weight: 800;
            color: var(--detective-amber);
            letter-spacing: 1.5px;
            text-transform: uppercase;
            box-shadow: 0 0 22px rgba(251, 191, 36, 0.40);
            animation: detective-badge-burst 0.7s cubic-bezier(0.18, 0.89, 0.32, 1.28);
        }

        @keyframes detective-badge-burst {
            0%   { opacity: 0; transform: scale(0.4); }
            60%  { opacity: 1; transform: scale(1.15); }
            100% { transform: scale(1); }
        }

        /* ----- Round-end results panel ----- */
        .detective-results {
            display: flex;
            flex-direction: column;
            gap: 14px;
            padding: 24px;
            background: linear-gradient(180deg, rgba(251, 191, 36, 0.10), rgba(251, 191, 36, 0.02));
            border: 1.5px dashed rgba(251, 191, 36, 0.45);
            border-radius: 14px;
            text-align: center;
            animation: detective-clue-slide-in 0.45s cubic-bezier(0.18, 0.89, 0.32, 1.28);
            grid-column: 1 / -1;
        }

        .detective-results-title {
            font-family: 'Space Grotesk', system-ui, sans-serif;
            font-size: 1.35rem;
            font-weight: 800;
            color: var(--detective-amber);
            letter-spacing: 0.5px;
            text-transform: uppercase;
        }

        .detective-results-stats {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 12px;
            font-size: 0.75rem;
            color: var(--text-secondary);
        }

        .detective-results-stat {
            padding: 12px;
            background: rgba(0, 0, 0, 0.30);
            border-radius: 10px;
            border: 1px solid rgba(255, 255, 255, 0.08);
        }

        .detective-results-stat-value {
            display: block;
            font-size: 1.3rem;
            font-weight: 800;
            color: var(--text-primary);
            margin-top: 4px;
            font-variant-numeric: tabular-nums;
        }

        /* ----- Responsive: collapse option grid + stat grid on narrow screens ----- */
        @media (max-width: 900px) {
            .detective-options { grid-template-columns: repeat(2, 1fr); }

        }
        @media (max-width: 720px) {
            .detective-options { grid-template-columns: 1fr; }
            .detective-stats { grid-template-columns: repeat(2, 1fr); }
            .detective-header { flex-direction: column; align-items: flex-start; }
            .detective-case-title { font-size: 1.1rem; }
            .detective-clue { padding: 22px 16px 16px; }
            .detective-clue-text { font-size: 0.95rem; }
            .detective-results-stats { grid-template-columns: 1fr; }
        }

/* ============================================================
   SLIDE 05 — Crude Oil Formation: Geographical Context
   (notes redesign matching slide_01's `.s01-history-notes` pattern)
   Scoped under `.s05-geography-notes` (and s05- prefixed selectors)
   to prevent cross-slide regressions. All visual properties
   reference the project tokens defined at :root above.
   ============================================================ */

.s05-geography-notes {
    color: var(--text-primary);
    font-family: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.55;
}

.s05-geography-notes .s05-section {
    margin-bottom: var(--space-4);
}
.s05-geography-notes .s05-section:last-child {
    margin-bottom: 0;
}

.s05-geography-notes .s05-section-heading {
    display: flex;
    align-items: center;
    gap: var(--space-1);
    font-size: 1rem;
    font-weight: 700;
    color: var(--electron);
    margin: 0 0 var(--space-2);
    letter-spacing: 0.01em;
}

.s05-geography-notes .s05-section-sub {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin: 0 0 var(--space-3);
}

.s05-geography-notes .s05-intro-section {
    padding: var(--space-3);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 0.75rem;
    border-left: 4px solid var(--neutron);
}
.s05-geography-notes .s05-intro-lede {
    margin: 0;
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--text-primary);
}
.s05-geography-notes .s05-intro-lede strong {
    color: var(--text-primary);
    font-weight: 600;
}
.s05-geography-notes .s05-intro-lede em {
    color: var(--neutron);
    font-style: normal;
    font-weight: 600;
}

.s05-geography-notes .s05-visuals-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 360px), 1fr));
    gap: var(--space-3);
    min-width: 0;
}

.s05-geography-notes .s05-visual-card {
    margin: 0;
    min-width: 0;
    padding: var(--space-3);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 0.75rem;
    -webkit-backdrop-filter: blur(8px);
    backdrop-filter: blur(8px);
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}
.s05-geography-notes .s05-visual-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
    border-color: rgba(59, 130, 246, 0.35);
}

.s05-geography-notes .s05-visual-head {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.s05-geography-notes .s05-visual-icon {
    font-size: 1.2rem;
    width: 34px;
    height: 34px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--glass-border);
    border-radius: 0.5rem;
    flex-shrink: 0;
}

.s05-geography-notes .s05-visual-title {
    margin: 0;
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.3;
    letter-spacing: 0.01em;
}

.s05-geography-notes .s05-svg-stage {
    width: 100%;
    max-width: 100%;
    overflow: hidden;
    border-radius: 0.5rem;
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--glass-border);
    padding: var(--space-1);
}
.s05-geography-notes .s05-svg-stage svg {
    display: block;
    width: 100%;
    height: auto;
    max-width: 100%;
}

.s05-geography-notes .s05-caption {
    margin: 0;
    font-size: 0.78rem;
    color: var(--text-secondary);
    font-style: italic;
    line-height: 1.45;
}

/* ---- Visual 1: geological cross-section animated trace dot ---- */
.s05-geography-notes .s05-visual-formation-card .s05-trace-wrap {
    /* The SVG is 600x360. The dot is supposed to travel from near the
       ocean surface (≈ y=110) to the reservoir rock (≈ y=338). */
    transform: translate(500px, 0);
    animation: s05-trace-flow 6.5s ease-in-out infinite;
    animation-delay: 1.2s;
    opacity: 0;
}

.s05-geography-notes .s05-visual-formation-card .s05-trace-dot {
    fill: var(--electron);
    stroke: rgba(255, 255, 255, 0.55);
    stroke-width: 1;
    filter: drop-shadow(0 0 6px var(--electron));
    animation: s05-trace-glow 1.6s ease-in-out infinite;
}

@keyframes s05-trace-flow {
    0%   { transform: translate(500px, 110px); opacity: 0; }
    8%   { opacity: 1; }
    25%  { transform: translate(500px, 210px); opacity: 1; }
    50%  { transform: translate(500px, 280px); opacity: 1; }
    75%  { transform: translate(400px, 320px); opacity: 1; }
    92%  { opacity: 1; }
    100% { transform: translate(470px, 340px); opacity: 0; }
}

@keyframes s05-trace-glow {
    0%, 100% {
        filter: drop-shadow(0 0 6px var(--electron)) drop-shadow(0 0 2px rgba(255, 255, 255, 0.45));
    }
    50% {
        filter: drop-shadow(0 0 14px var(--electron)) drop-shadow(0 0 5px rgba(255, 255, 255, 0.75));
    }
}

/* ---- Visual 2: bar chart subtle value-rise animation ---- */
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect {
    transform-box: fill-box;
    transform-origin: bottom center;
    animation: s05-bar-rise 0.9s cubic-bezier(0.2, 0.7, 0.3, 1) backwards;
}
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(1)  { animation-delay: 0.05s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(2)  { animation-delay: 0.12s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(3)  { animation-delay: 0.19s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(4)  { animation-delay: 0.26s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(5)  { animation-delay: 0.05s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(6)  { animation-delay: 0.12s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(7)  { animation-delay: 0.19s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(8)  { animation-delay: 0.26s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(9)  { animation-delay: 0.05s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(10) { animation-delay: 0.12s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(11) { animation-delay: 0.19s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(12) { animation-delay: 0.26s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(13) { animation-delay: 0.05s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(14) { animation-delay: 0.12s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(15) { animation-delay: 0.19s; }
.s05-geography-notes .s05-visual-card:nth-of-type(2) rect:nth-of-type(16) { animation-delay: 0.26s; }

@keyframes s05-bar-rise {
    0%   { transform: scaleY(0);   opacity: 0.4; }
    100% { transform: scaleY(1);   opacity: 1; }
}

/* ---- Visual 3: organism cards gentle float ---- */
.s05-geography-notes .s05-visual-card:nth-of-type(3) > .s05-svg-stage > svg > g > g:nth-of-type(2),
.s05-geography-notes .s05-visual-card:nth-of-type(3) > .s05-svg-stage > svg > g > g:nth-of-type(3),
.s05-geography-notes .s05-visual-card:nth-of-type(3) > .s05-svg-stage > svg > g > g:nth-of-type(4) {
    transform-box: fill-box;
    transform-origin: center;
    animation: s05-org-float 4s ease-in-out infinite;
}
.s05-geography-notes .s05-visual-card:nth-of-type(3) > .s05-svg-stage > svg > g:nth-of-type(2) > g:nth-of-type(2) { animation-delay: 0s; }
.s05-geography-notes .s05-visual-card:nth-of-type(3) > .s05-svg-stage > svg > g:nth-of-type(3) > g:nth-of-type(2) { animation-delay: 0.6s; }
.s05-geography-notes .s05-visual-card:nth-of-type(3) > .s05-svg-stage > svg > g:nth-of-type(4) > g:nth-of-type(2) { animation-delay: 1.2s; }

@keyframes s05-org-float {
    0%, 100% { transform: translateY(0); }
    50%      { transform: translateY(-4px); }
}

/* ---- Visual 4: API/sulfur markers soft pulse ---- */
.s05-geography-notes .s05-visual-card:nth-of-type(4) circle {
    transform-box: fill-box;
    transform-origin: center;
    animation: s05-marker-pulse 3.2s ease-in-out infinite;
}
.s05-geography-notes .s05-visual-card:nth-of-type(4) circle:nth-of-type(1) { animation-delay: 0s; }
.s05-geography-notes .s05-visual-card:nth-of-type(4) circle:nth-of-type(2) { animation-delay: 0.4s; }
.s05-geography-notes .s05-visual-card:nth-of-type(4) circle:nth-of-type(3) { animation-delay: 0.8s; }
.s05-geography-notes .s05-visual-card:nth-of-type(4) circle:nth-of-type(4) { animation-delay: 1.2s; }
.s05-geography-notes .s05-visual-card:nth-of-type(4) circle:nth-of-type(5) { animation-delay: 1.6s; }
.s05-geography-notes .s05-visual-card:nth-of-type(4) circle:nth-of-type(6) { animation-delay: 2.0s; }

@keyframes s05-marker-pulse {
    0%, 100% { transform: scale(1);   opacity: 1; }
    50%      { transform: scale(1.18); opacity: 0.85; }
}

/* ---- Info card ---- */
.s05-geography-notes .s05-info-card {
    padding: var(--space-3);
    background: rgba(59, 130, 246, 0.08);
    border: 1px solid rgba(59, 130, 246, 0.30);
    border-left: 4px solid var(--neutron);
    border-radius: 0.5rem;
    font-size: 0.9rem;
    line-height: 1.6;
    color: var(--text-primary);
}
.s05-geography-notes .s05-info-card strong { color: var(--neutron); }
.s05-geography-notes .s05-info-card em {
    color: var(--success);
    font-style: normal;
    font-weight: 600;
}

/* ---- Exam questions ---- */
.s05-geography-notes .s05-questions-head {
    margin-bottom: var(--space-2);
}

.s05-geography-notes .s05-question-card {
    margin-bottom: var(--space-3);
    padding: var(--space-3);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-left: 4px solid var(--glass-border);
    border-radius: 0.5rem;
    transition: transform 0.25s ease, box-shadow 0.25s ease, border-left-color 0.25s ease;
}
.s05-geography-notes .s05-question-card:last-child {
    margin-bottom: 0;
}
.s05-geography-notes .s05-question-card:hover {
    transform: translateX(4px);
    box-shadow: 0 6px 18px rgba(0, 0, 0, 0.35);
}

.s05-geography-notes .s05-question-card.s05-q-1 { border-left-color: var(--electron); }
.s05-geography-notes .s05-question-card.s05-q-2 { border-left-color: var(--neutron);  }
.s05-geography-notes .s05-question-card.s05-q-3 { border-left-color: var(--proton);   }
.s05-geography-notes .s05-question-card.s05-q-4 { border-left-color: var(--success);  }

.s05-geography-notes .s05-question-head {
    display: flex;
    align-items: flex-start;
    gap: var(--space-2);
    margin-bottom: var(--space-1);
}

.s05-geography-notes .s05-question-text {
    margin: 0;
    flex: 1;
    font-size: 0.92rem;
    line-height: 1.55;
    color: var(--text-primary);
}
.s05-geography-notes .s05-question-text strong {
    color: var(--text-primary);
    margin-right: 4px;
    font-weight: 700;
}

.s05-geography-notes .s05-mark-badge {
    flex-shrink: 0;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 64px;
    padding: 4px 10px;
    border-radius: 999px;
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid currentColor;
    color: var(--text-secondary);
    line-height: 1.2;
    text-align: center;
}

.s05-geography-notes .s05-mark-badge.s05-mark-1 {
    color: var(--electron);
    background: rgba(234, 179, 8, 0.10);
}
.s05-geography-notes .s05-mark-badge.s05-mark-2 {
    color: var(--neutron);
    background: rgba(59, 130, 246, 0.10);
}
.s05-geography-notes .s05-mark-badge.s05-mark-4 {
    color: var(--proton);
    background: rgba(239, 68, 68, 0.10);
}
.s05-geography-notes .s05-mark-badge.s05-mark-6 {
    color: var(--success);
    background: rgba(34, 197, 94, 0.10);
}

/* Container-responsive: collapse card padding on narrow viewports */
@container (max-width: 520px) {
    .s05-geography-notes .s05-visual-card {
        padding: var(--space-2);
    }
    .s05-geography-notes .s05-mark-badge {
        min-width: 56px;
        font-size: 0.68rem;
    }
}

@media (max-width: 520px) {
    .s05-geography-notes .s05-visual-card {
        padding: var(--space-2);
    }
    .s05-geography-notes .s05-mark-badge {
        min-width: 56px;
        font-size: 0.68rem;
    }
}

/* Reduced-motion: freeze animations and place the trace dot in a stable position */
@media (prefers-reduced-motion: reduce) {
    .s05-geography-notes .s05-trace-wrap,
    .s05-geography-notes .s05-trace-dot,
    .s05-geography-notes .s05-visual-card:nth-of-type(2) rect,
    .s05-geography-notes .s05-visual-card:nth-of-type(3) g g,
    .s05-geography-notes .s05-visual-card:nth-of-type(4) circle,
    .s05-geography-notes .anim-fade-up,
    .s05-geography-notes .stagger-1,
    .s05-geography-notes .stagger-2,
    .s05-geography-notes .stagger-3,
    .s05-geography-notes .stagger-4,
    .s05-geography-notes .ambient-count,
    .s05-geography-notes .ambient-pulse,
    .s05-geography-notes .ambient-glow {
        animation: none !important;
    }
    .s05-geography-notes .s05-trace-wrap {
        opacity: 0.85;
        transform: translate(470px, 260px);
    }
    .s05-geography-notes .s05-visual-card:nth-of-type(2) rect {
        transform: scaleY(1);
        opacity: 1;
    }
}