.conversion-card {
            background: white;
            border-radius: 12px;
            box-shadow: 0 2px 8px rgba(0,0,0,0.05);
            padding: 1.5rem;
            margin: 1.5rem 0;
            border: 1px solid #e9ecef;
        }
        .mode-switch {
            display: flex;
            gap: 1rem;
            margin-bottom: 1.5rem;
            border-bottom: 1px solid #dee2e6;
            padding-bottom: 0.75rem;
        }
        .mode-btn {
            background: none;
            border: none;
            font-size: 1.1rem;
            font-weight: 500;
            padding: 0.5rem 1rem;
            border-radius: 30px;
            transition: 0.2s;
            color: #6c757d;
        }
        .mode-btn.active {
            background: var(--primary-color, #0d6efd);
            color: white;
        }
        .io-panel {
            margin-top: 1rem;
        }
        .io-label {
            font-weight: 600;
            margin-bottom: 0.5rem;
            display: flex;
            justify-content: space-between;
            align-items: baseline;
        }
        .io-textarea {
            width: 100%;
            min-height: 150px;
            font-family: 'Courier New', monospace;
            font-size: 0.95rem;
            padding: 0.75rem;
            border: 1px solid #ced4da;
            border-radius: 8px;
            resize: vertical;
        }
        .action-buttons {
            display: flex;
            flex-wrap: wrap;
            gap: 0.75rem;
            margin: 1rem 0;
        }
        .char-counter {
            font-size: 0.8rem;
            color: #6c757d;
        }
        .spec-box {
            background-color: #f8f9fa;
            border-radius: 8px;
            padding: 1rem;
            margin: 1.5rem 0;
            border-left: 4px solid var(--primary-color);
        }
        .table-encoding {
            width: 100%;
            font-size: 0.9rem;
            border-collapse: collapse;
        }
        .table-encoding td, .table-encoding th {
            padding: 0.75rem;
            border: 1px solid #dee2e6;
        }
        .table-encoding thead th {
            background-color: #e9ecef;
            font-weight: 600;
        }
        .table-encoding tbody tr:nth-child(even) {
            background-color: #f8f9fa;
        }
        .badge-rfc {
            background: linear-gradient(135deg, #6f42c1, #20c997);
            color: white;
        }
        .privacy-badge {
            display: inline-flex;
            align-items: center;
            background-color: #d1f7e5;
            color: #0d6832;
            padding: 0.4rem 0.8rem;
            border-radius: 20px;
            font-size: 0.85rem;
            font-weight: 600;
            margin-left: 1rem;
        }
        .interactive-char {
            cursor: pointer;
            padding: 0.2rem 0.5rem;
            border-radius: 4px;
            transition: background-color 0.2s;
        }
        .interactive-char:hover {
            background-color: #e7f1ff;
        }
        .quick-test-area {
            background-color: #f8f9fa;
            border-radius: 8px;
            padding: 1rem;
            margin-top: 1rem;
        }