:root {
            /* Algebra Domain / Rose Theme override */
            --color-rose: #f43f5e;
            --color-rose-glow: rgba(244, 63, 94, 0.35);
            --color-accent: #f43f5e;
            --color-accent-glow: rgba(244, 63, 94, 0.35);

            --color-expr: #38bdf8;   /* Cyan for Expressions */
            --color-eq: #10b981;     /* Emerald for Equations */
            --color-box: #a855f7;    /* Purple for Variable Box */
            --color-coin: #ffb000;   /* Gold for Coins */
        }

        /* Highlight classes on sidebar active menu */
        .sidebar-drawer .syllabus-item.active a {
            background: var(--color-rose) !important;
            box-shadow: 0 4px 20px var(--color-rose-glow) !important;
        }

        section {
            margin-bottom: 6rem;
            scroll-margin-top: 2rem;
        }

        .section-header {
            display: flex;
            align-items: center;
            gap: 12px;
            margin-bottom: 1.75rem;
        }

        .section-tag {
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.8rem;
            color: var(--color-rose);
            background: rgba(244, 63, 94, 0.1);
            padding: 4px 10px;
            border-radius: 6px;
            border: 1px solid rgba(244, 63, 94, 0.2);
            text-shadow: 0 0 5px var(--color-rose-glow);
        }

        .section-header h2 {
            font-size: 1.75rem;
            font-weight: 700;
        }

        .section-intro {
            color: var(--text-muted);
            margin-bottom: 2rem;
            line-height: 1.6;
            font-size: 1rem;
            max-width: 850px;
        }

        /* Math Display styling */
        .equation-box {
            font-family: 'Outfit', sans-serif;
            font-size: 1.5rem;
            font-weight: 700;
            text-align: center;
            padding: 1.25rem;
            background: rgba(255, 255, 255, 0.015);
            border-radius: 16px;
            border: 1px dashed rgba(255, 255, 255, 0.06);
            margin-bottom: 1.5rem;
            color: var(--text-color);
        }

        /* Control Sliders */
        .slider-group {
            display: flex;
            flex-direction: column;
            gap: 1.25rem;
            margin-bottom: 1.5rem;
        }

        .slider-row {
            display: flex;
            flex-direction: column;
            gap: 6px;
        }

        .slider-label {
            display: flex;
            justify-content: space-between;
            font-size: 0.9rem;
            font-weight: 500;
            color: var(--text-muted);
        }

        .slider-row input[type="range"] {
            -webkit-appearance: none;
            width: 100%;
            height: 6px;
            background: rgba(255, 255, 255, 0.08);
            border-radius: 3px;
            outline: none;
            margin: 8px 0;
        }

        .slider-row input[type="range"]::-webkit-slider-thumb {
            -webkit-appearance: none;
            width: 16px;
            height: 16px;
            border-radius: 50%;
            background: var(--color-rose);
            cursor: pointer;
            box-shadow: 0 0 8px var(--color-rose-glow);
        }

        /* Preset select */
        .select-preset {
            width: 100%;
            background: rgba(0, 0, 0, 0.3);
            border: 1px solid var(--card-border);
            color: var(--text-color);
            font-family: 'Outfit', sans-serif;
            font-size: 0.9rem;
            padding: 8px 12px;
            border-radius: 8px;
            outline: none;
            margin-bottom: 1.5rem;
            cursor: pointer;
        }

        /* Sorter Card Arena */
        .sorter-container {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 2rem;
            margin-top: 1.5rem;
        }

        @media (max-width: 768px) {
            .sorter-container {
                grid-template-columns: 1fr;
            }
        }

        .sorter-column {
            background: rgba(255, 255, 255, 0.01);
            border: 1px solid var(--card-border);
            border-radius: 16px;
            padding: 1.25rem;
            min-height: 250px;
            display: flex;
            flex-direction: column;
            gap: 10px;
        }

        .sorter-col-title {
            font-weight: 700;
            font-size: 0.95rem;
            margin-bottom: 0.5rem;
            display: flex;
            align-items: center;
            gap: 8px;
        }

        .sorter-card-pile {
            background: rgba(255, 255, 255, 0.015);
            border: 1px solid var(--card-border);
            border-radius: 16px;
            padding: 1.5rem;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            text-align: center;
            margin-bottom: 1.5rem;
            position: relative;
            min-height: 180px;
        }

        .active-sort-card {
            font-family: 'JetBrains Mono', monospace;
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--text-color);
            margin-bottom: 1.5rem;
            background: rgba(0, 0, 0, 0.2);
            padding: 10px 20px;
            border-radius: 10px;
            border: 1px solid rgba(255, 255, 255, 0.05);
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
        }

        .sort-buttons-row {
            display: flex;
            gap: 12px;
            width: 100%;
            max-width: 300px;
        }

        .btn-sort {
            flex: 1;
            padding: 0.6rem;
            border-radius: 10px;
            font-weight: 600;
            font-family: 'Outfit';
            font-size: 0.85rem;
            cursor: pointer;
            border: none;
            transition: all var(--transition-speed) ease;
        }

        .btn-sort.expr {
            background: var(--color-expr);
            color: #000000;
            box-shadow: 0 4px 10px rgba(56, 189, 248, 0.25);
        }
        .btn-sort.expr:hover {
            transform: translateY(-1px);
            box-shadow: 0 6px 15px rgba(56, 189, 248, 0.4);
        }

        .btn-sort.eq {
            background: var(--color-eq);
            color: #000000;
            box-shadow: 0 4px 10px rgba(16, 185, 129, 0.25);
        }
        .btn-sort.eq:hover {
            transform: translateY(-1px);
            box-shadow: 0 6px 15px rgba(16, 185, 129, 0.4);
        }

        .sorted-item-badge {
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.85rem;
            padding: 6px 12px;
            border-radius: 8px;
            background: rgba(255,255,255,0.02);
            border: 1px solid var(--card-border);
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .sorted-item-badge.correct { border-color: rgba(16, 185, 129, 0.2); color: #10b981; }
        .sorted-item-badge.incorrect { border-color: rgba(244, 63, 94, 0.2); color: #f43f5e; }

        /* Truth Tester */
        .truth-btn-row {
            display: flex;
            gap: 8px;
            margin-bottom: 1.5rem;
            flex-wrap: wrap;
        }

        .btn-truth-test {
            background: rgba(255, 255, 255, 0.02);
            color: var(--text-muted);
            border: 1px solid var(--card-border);
            padding: 6px 14px;
            border-radius: 8px;
            font-size: 0.85rem;
            font-family: 'JetBrains Mono', monospace;
            cursor: pointer;
            transition: all var(--transition-speed) ease;
        }

        .btn-truth-test:hover {
            color: var(--text-color);
            background: rgba(255, 255, 255, 0.05);
        }

        .btn-truth-test.selected-true {
            color: #10b981;
            background: rgba(16, 185, 129, 0.1);
            border-color: rgba(16, 185, 129, 0.35);
        }

        .btn-truth-test.selected-false {
            color: #f43f5e;
            background: rgba(244, 63, 94, 0.1);
            border-color: rgba(244, 63, 94, 0.35);
        }

        .evaluation-console {
            background: rgba(0, 0, 0, 0.25);
            border-radius: 12px;
            border: 1px solid var(--card-border);
            padding: 1.25rem;
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.85rem;
            line-height: 1.6;
            min-height: 140px;
        }

        /* Quiz layout rules */
        .quiz-option {
            background: rgba(255, 255, 255, 0.015);
            border: 1px solid var(--card-border);
            border-radius: 12px;
            padding: 1rem 1.25rem;
            margin-bottom: 0.75rem;
            cursor: pointer;
            transition: all var(--transition-speed) ease;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .quiz-option:hover {
            background: rgba(255, 255, 255, 0.04);
            border-color: rgba(255, 255, 255, 0.1);
            transform: translateX(4px);
        }

        .quiz-option.correct {
            background: rgba(16, 185, 129, 0.08);
            border-color: rgba(16, 185, 129, 0.3);
            color: #10b981;
        }

        .quiz-option.incorrect {
            background: rgba(244, 63, 94, 0.08);
            border-color: rgba(244, 63, 94, 0.3);
            color: #f43f5e;
        }

        .quiz-feedback {
            margin-top: 1rem;
            padding: 1rem;
            border-radius: 12px;
            background: rgba(255, 255, 255, 0.02);
            border: 1px solid var(--card-border);
            font-size: 0.9rem;
            line-height: 1.5;
            display: none;
        }

        .quiz-score-overlay {
            text-align: center;
            padding: 2rem;
            background: rgba(0, 0, 0, 0.2);
            border-radius: 16px;
            border: 1px solid var(--card-border);
        }