.roman-symbol-grid {
            display: flex;
            flex-wrap: wrap;
            gap: 1rem;
            justify-content: center;
            margin: 1rem 0;
        }
        .roman-symbol-card {
            background: white;
            border-radius: 12px;
            padding: 0.75rem 1.2rem;
            box-shadow: 0 2px 6px rgba(0,0,0,0.05);
            border: 1px solid #e9ecef;
            font-family: 'Courier New', monospace;
            font-weight: bold;
            text-align: center;
        }
        .roman-symbol-card span:first-child {
            font-size: 1.8rem;
            font-weight: 700;
            color: #2c3e66;
        }
        .roman-symbol-card span:last-child {
            display: block;
            font-size: 0.9rem;
            color: #6c757d;
        }
        .conversion-panel {
            background-color: #f8fafc;
            border-radius: 1rem;
            padding: 1.5rem;
            margin-bottom: 1.5rem;
            border: 1px solid #e2e8f0;
            transition: all 0.2s;
        }
        .result-badge {
            font-size: 2rem;
            font-weight: 700;
            font-family: 'Courier New', monospace;
            background: #f1f5f9;
            padding: 0.8rem 1.2rem;
            border-radius: 1rem;
            text-align: center;
            letter-spacing: 1px;
            word-break: break-word;
        }
        .step-explanation {
            background-color: #ffffff;
            border-left: 4px solid #2c3e66;
            padding: 0.8rem 1rem;
            font-size: 0.9rem;
            margin-top: 0.8rem;
            border-radius: 0 0.5rem 0.5rem 0;
        }
        .quick-examples {
            display: flex;
            flex-wrap: wrap;
            gap: 0.6rem;
            margin: 1rem 0;
        }
        .quick-btn {
            background: #eef2ff;
            border: none;
            border-radius: 40px;
            padding: 0.4rem 1rem;
            font-family: monospace;
            font-weight: 500;
            transition: 0.1s;
        }
        .quick-btn:hover {
            background: #cbd5e1;
            transform: translateY(-2px);
        }
        .validation-feedback {
            font-size: 0.85rem;
            margin-top: 0.3rem;
        }
        .roman-numeral-lg {
            font-size: 2rem;
            font-weight: bold;
            font-family: 'Times New Roman', serif;
            letter-spacing: 2px;
        }
        .demo-step-container {
            background: #f8f9fa;
            border-radius: 0.5rem;
            padding: 1.5rem;
            margin-top: 1rem;
            border-left: 4px solid #0d6efd;
        }
        .step-list {
            list-style-type: none;
            padding-left: 0;
        }
        .step-list li {
            padding: 0.5rem 0.75rem;
            margin-bottom: 0.5rem;
            background: white;
            border-radius: 0.25rem;
            border-left: 3px solid transparent;
            transition: all 0.3s ease;
        }
        .step-list li.active-step {
            border-left-color: #0d6efd;
            background-color: #e7f1ff;
            font-weight: 600;
        }
        .step-list li.completed-step {
            border-left-color: #198754;
            color: #6c757d;
        }
        .timeline {
            position: relative;
            padding-left: 2rem;
            margin: 1.5rem 0;
        }
        .timeline:before {
            content: '';
            position: absolute;
            left: 7px;
            top: 0;
            bottom: 0;
            width: 2px;
            background: #dee2e6;
        }
        .timeline-item {
            position: relative;
            margin-bottom: 1.5rem;
        }
        .timeline-item:before {
            content: '';
            position: absolute;
            left: -1.625rem;
            top: 0.25rem;
            width: 12px;
            height: 12px;
            border-radius: 50%;
            background: #2c3e66;
            border: 2px solid white;
            box-shadow: 0 0 0 3px #2c3e66;
        }
        .timeline-year {
            font-weight: bold;
            color: #2c3e66;
        }