.isotope-table {
            background: white;
            border-radius: 8px;
            overflow-x: auto;
        }
        .isotope-table th {
            background-color: #f1f4f9;
        }
        .abundance-warning {
            background-color: #fff3cd;
            border-left: 5px solid #ffc107;
            padding: 10px 15px;
            border-radius: 6px;
            margin: 15px 0;
        }
        .result-card {
            background: linear-gradient(135deg, #f5f7fc 0%, #eef2f9 100%);
            border-radius: 16px;
            padding: 1.5rem;
            text-align: center;
            box-shadow: 0 4px 12px rgba(0,0,0,0.05);
        }
        .atomic-mass-value {
            font-size: 2.8rem;
            font-weight: 700;
            color: #1e466e;
            font-family: 'Courier New', monospace;
        }
        .mass-unit {
            font-size: 1.2rem;
            color: #4a627a;
        }
        .btn-preset {
            background-color: #e9ecef;
            border-color: #ced4da;
            margin: 0.2rem;
        }
        .element-selector {
            background: #f8f9fa; 
            border-radius: 12px;
            margin-bottom: 20px;
        }
        .periodic-badge {
            font-size: 0.9rem;
            background: #e9ecef;
            border-radius: 20px;
            padding: 5px 12px;
            margin: 2px;
            display: inline-block;
            cursor: pointer;
            transition: 0.1s;
        }
        .periodic-badge:hover {
            background: #cbd5e1;
        }
        .reference-block {
            font-size: 0.85rem;
            background: #f9fafb;
            border-top: 1px solid #e2e8f0;
            margin-top: 1.5rem;
            padding-top: 1rem;
        }
        .legend-chart {
            display: flex;
            gap: 1rem;
            justify-content: center;
            font-size: 0.8rem;
            margin-top: 0.5rem;
        }
        .legend-color {
            width: 14px;
            height: 14px;
            background: #2c7da0;
            display: inline-block;
            border-radius: 2px;
        }
        .author-badge {
            background: #eef2fa;
            padding: 1rem;
            border-radius: 12px;
        }
        .loading-data {
            font-size: 0.8rem;
            color: #2c7da0;
        }