*{box-sizing:border-box}body{color:#333;font-family:Arial,sans-serif;margin:0;min-height:100vh}.container,body{background:#fff;padding:20px}.container{border:1px solid #ddd;border-radius:8px;margin:0 auto;max-width:600px}h1{color:#333;font-size:24px;margin:0 0 20px;text-align:center}h3{color:#555;font-size:16px;margin:20px 0 10px}.card-form{padding:0}.card-logos{display:flex;flex-wrap:wrap;gap:10px;justify-content:center;margin-bottom:20px}.card-logo{background:#f9f9f9;border:1px solid #ccc;border-radius:4px;height:32px;object-fit:contain;opacity:.5;padding:2px;transition:all .2s ease;width:50px}.card-logo.active{background:#e3f2fd;border-color:#007bff;opacity:1}.card-logo.valid{background:#d4edda;border-color:#28a745}.card-logo.invalid{background:#f8d7da;border-color:#dc3545}.input-container{margin-bottom:20px}#cardInput{border:1px solid #ccc;border-radius:4px;font-family:Courier New,monospace;font-size:16px;letter-spacing:1px;outline:none;padding:12px;transition:border-color .2s ease;width:100%}#cardInput:focus{border-color:#007bff}#cardInput.valid{background-color:#f8fff8;border-color:#28a745}#cardInput.invalid{background-color:#fff8f8;border-color:#dc3545}.validation-result{border-radius:4px;font-weight:500;margin-top:10px;min-height:20px;padding:8px;transition:all .2s ease}.validation-result.valid{background-color:#d4edda;border:1px solid #c3e6cb;color:#28a745}.validation-result.invalid{background-color:#f8d7da;border:1px solid #f5c6cb;color:#dc3545}.validation-result.empty{display:none}.test-cards{background:#f8f9fa;border:1px solid #e9ecef;border-radius:4px;margin-top:20px;padding:15px}.test-card-list{display:flex;flex-direction:column;gap:8px}.test-card{background:#fff;border:1px solid #dee2e6;border-radius:4px;font-family:Courier New,monospace;font-size:14px;padding:8px}.test-card strong{color:#007bff;margin-right:10px}@media (max-width:480px){.container{margin:10px;padding:15px}.card-logo{height:25px;width:40px}h1{font-size:20px}}