: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-square-a: #f43f5e; /* Rose */
            --color-square-b: #38bdf8; /* Cyan */
            --color-rect-ab: #a855f7;  /* Purple */
        }

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

        section {
            margin-bottom: 5rem;
            scroll-margin-top: 2rem;
        }

        .section-header {
            display: flex;
            align-items: center;
            gap: 12px;
            margin-bottom: 1.5rem;
        }

        .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;
        }

        /* Identity Cards Grid */
        .identity-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 1.5rem;
            margin-top: 1.5rem;
        }

        .identity-card {
            background: rgba(13, 16, 23, 0.65);
            border: 1px solid var(--card-border);
            border-radius: 20px;
            padding: 1.75rem;
            backdrop-filter: blur(16px);
            transition: all var(--transition-speed) ease;
            display: flex;
            flex-direction: column;
            justify-content: space-between;
            cursor: pointer;
            position: relative;
            min-height: 440px;
            height: auto;
        }

        .identity-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 3px;
            background: var(--color-rose);
            opacity: 0.5;
            transition: all var(--transition-speed) ease;
        }

        .identity-card:hover {
            transform: translateY(-5px);
            border-color: rgba(244, 63, 94, 0.4);
            box-shadow: 0 15px 35px rgba(244, 63, 94, 0.08), 0 5px 15px rgba(0, 0, 0, 0.4);
        }

        .identity-card:hover::before {
            opacity: 1;
            box-shadow: 0 0 10px var(--color-rose-glow);
        }

        .identity-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 0.75rem;
        }

        .identity-num {
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.85rem;
            color: var(--text-muted);
        }

        .identity-formula {
            font-family: 'JetBrains Mono', monospace;
            font-size: 1.15rem;
            font-weight: 700;
            color: #fff;
            margin-bottom: 1.25rem;
            word-break: break-all;
        }

        .identity-title {
            font-size: 1.25rem;
            font-weight: 700;
            margin-bottom: 0.5rem;
        }

        .identity-desc {
            color: var(--text-muted);
            font-size: 0.875rem;
            line-height: 1.5;
            margin-bottom: 1rem;
            flex-grow: 1;
        }

        .preview-canvas-container {
            width: 100%;
            height: 150px;
            background: rgba(0, 0, 0, 0.2);
            border-radius: 12px;
            border: 1px solid rgba(255, 255, 255, 0.04);
            display: flex;
            align-items: center;
            justify-content: center;
            margin-bottom: 1rem;
            overflow: hidden;
        }

        .btn-launch {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
            background: rgba(244, 63, 94, 0.1);
            color: var(--color-rose);
            border: 1px solid rgba(244, 63, 94, 0.25);
            padding: 0.6rem 1rem;
            border-radius: 10px;
            font-size: 0.85rem;
            font-weight: 600;
            text-decoration: none;
            transition: all var(--transition-speed) ease;
        }

        .identity-card:hover .btn-launch {
            background: var(--color-rose);
            color: #fff;
            box-shadow: 0 4px 15px var(--color-rose-glow);
        }