body {
            background: linear-gradient(135deg, #3498db 0%,#4b9c7b 100%);
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 20px;
        }
        
        .card {
            border-radius: 12px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
            border: none;
            min-width: 100%;
        }
        
        .card-header {
            background-color: white;
            border-bottom: 1px solid #e0e0e0;
            padding: 20px 30px;
        }
        
        .card-body {
            padding: 30px;
        }
        
        .input-group-text {
            background-color: #e9ecef;
            border: 1px solid #ced4da;
        }
        
        .result-card {
            background-color: #f8f9fa;
            border-radius: 8px;
            padding: 20px;
            border-left: 4px solid #3498db;
        }
        
        .status-found {
            background-color: #d4edda;
            color: #155724;
        }
        
        .status-not-found {
            background-color: #f8d7da;
            color: #721c24;
        }
        
        .extracted-utr {
            background-color: #fff3cd;
            border: 1px solid #ffeaa7;
            border-radius: 4px;
            padding: 10px;
            margin: 10px 0;
            font-family: monospace;
        }
        
        .instructions {
            background-color: #fff9e6;
            border-left: 4px solid #f1c40f;
            padding: 15px;
            border-radius: 0 6px 6px 0;
        }
        
        .api-info {
            background-color: #e8f5e9;
            border-left: 4px solid #4caf50;
            padding: 15px;
            margin-top: 20px;
            border-radius: 0 6px 6px 0;
            font-size: 14px;
        }
        
        .history-list {
            max-height: 200px;
            overflow-y: auto;
            border: 1px solid #e0e0e0;
            border-radius: 6px;
            padding: 10px;
        }
        
        .loading {
            display: inline-block;
            width: 20px;
            height: 20px;
            border: 3px solid rgba(255,255,255,.3);
            border-radius: 50%;
            border-top-color: #fff;
            animation: spin 1s ease-in-out infinite;
            margin-right: 10px;
        }
        
        @keyframes spin {
            to { transform: rotate(360deg); }
        }
        
        .last-updated {
            text-align: center;
            color: #6c757d;
            margin-bottom: 15px;
            line-height: 1.5;
            font-size: 14px;
            font-style: italic;
        }
        
        .detail-row {
            display: flex;
            margin-bottom: 8px;
            padding-bottom: 8px;
            border-bottom: 1px solid #e9ecef;
        }
        
        .detail-label {
            font-weight: 600;
            color: #6c757d;
            width: 150px;
        }
        
        .detail-value {
            color: #2c3e50;
            flex: 1;
            word-break: break-all;
        }
        
        .sheet-selector {
            min-width: 180px;
        }
        
        /* Validation styles */
        .error-message {
            color: #dc3545;
            font-size: 0.875em;
            margin-top: 0.25rem;
            display: none;
        }
        
        .is-invalid {
            border-color: #dc3545 !important;
            background-color: #fff0f0 !important;
        }
        
        .is-valid {
            border-color: #198754 !important;
            background-color: #f0fff0 !important;
        }
        
        /* New responsive styles */
        .search-controls {
            display: flex;
            flex-direction: row;
            gap: 15px;
            align-items: flex-end;
        }
        
        .search-field {
            flex: 1;
        }
        
        .search-actions {
            display: flex;
            gap: 10px;
        }
        
        .sheet-selector-container {
            flex: 1;
        }
        
        .utr-input-container {
            flex: 2;
        }
        
        @media (max-width: 768px) {
            .search-controls {
                flex-direction: column;
                align-items: center;
                text-align: center;
                gap: 20px;
            }
            
            .sheet-selector-container,
            .utr-input-container {
                width: 100%;
                max-width: 400px;
            }
            
            .search-actions {
                width: 100%;
                justify-content: center;
            }
            
            .detail-row {
                flex-direction: column;
                text-align: center;
            }
            
            .detail-label {
                width: 100%;
                margin-bottom: 5px;
            }
            
            .detail-value {
                width: 100%;
            }
        }
        
        @media (max-width: 576px) {
            .card-body {
                padding: 20px 15px;
            }
            
            .card-header {
                padding: 15px 20px;
            }
            
            .search-field {
                min-width: 100%;
            }
            
            .search-actions {
                flex-direction: column;
                width: 100%;
                max-width: 300px;
            }
            
            .search-actions .btn {
                width: 100%;
            }
        }