* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.main-container {
    display: flex;
    gap: 30px;
    max-width: 1200px;
    margin: 0 auto;
    align-items: stretch;
}

.test-cards-panel {
    background: white;
    border-radius: 16px;
    padding: 30px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    flex: 0 0 320px;
    position: sticky;
    top: 20px;
    display: flex;
    flex-direction: column;
}

.test-cards-panel h2 {
    color: #333;
    margin-bottom: 20px;
    font-size: 20px;
    text-align: center;
}

.test-card-description {
    color: #666;
    margin-bottom: 8px;
    font-size: 14px;
    text-align: center;
}

.test-card-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
    flex: 1;
}

.test-card-item {
    padding: 12px;
    background: #f8f9fa;
    border-radius: 8px;
    border: 1px solid #e0e0e0;
    transition: all 0.2s;
    cursor: pointer;
    position: relative;
    user-select: none;
}

.test-card-item:hover {
    background: #e9ecef;
    border-color: #667eea;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.test-card-label {
    font-size: 12px;
    color: #666;
    margin-bottom: 6px;
    font-weight: 500;
}

.test-card-number {
    font-size: 14px;
    color: #333;
    font-family: 'Courier New', monospace;
    user-select: none;
}

.copied-indicator {
    position: absolute;
    top: 23%;
    right: 0px;
    transform: translateY(-50%);
    background: #28a745;
    color: white;
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 12px;
    font-weight: 500;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease-out;
    z-index: 10;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    white-space: nowrap;
}

.copied-indicator.show {
    opacity: 1;
    animation: fadeOut 2s ease-out forwards;
}

@keyframes fadeOut {
    0% {
        opacity: 1;
        transform: translateY(-50%) scale(1);
    }
    70% {
        opacity: 1;
        transform: translateY(-50%) scale(1);
    }
    100% {
        opacity: 0;
        transform: translateY(-50%) scale(0.9);
    }
}

.test-card-note {
    margin-top: auto;
    font-size: 12px;
    color: #666;
    text-align: center;
    font-style: italic;
    padding-top: 20px;
}

.container {
    width: 100%;
    max-width: 500px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

@media (max-width: 968px) {
    .main-container {
        flex-direction: column;
    }
    
    .test-cards-panel {
        flex: 1;
        position: static;
        width: 100%;
    }
    
    .container {
        max-width: 100%;
    }
}

.payment-card {
    background: white;
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    display: flex;
    flex-direction: column;
    height: 100%;
}

#payment-form {
    display: flex;
    flex-direction: column;
    flex: 1;
}

h1 {
    color: #333;
    margin-bottom: 30px;
    text-align: center;
    font-size: 28px;
}

.product-info {
    text-align: center;
    margin-bottom: 30px;
    padding-bottom: 30px;
    border-bottom: 2px solid #f0f0f0;
}

.product-info h2 {
    color: #333;
    margin-bottom: 10px;
    font-size: 22px;
}

.description {
    color: #666;
    margin-bottom: 15px;
    font-size: 14px;
}

.price {
    font-size: 36px;
    font-weight: bold;
    color: #667eea;
    margin-top: 10px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #333;
    font-weight: 500;
    font-size: 14px;
}

#amount-input {
    width: 100%;
    padding: 12px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s;
}

#amount-input:focus {
    outline: none;
    border-color: #667eea;
}

.card-element {
    padding: 12px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    margin-bottom: 20px;
    background: white;
    transition: border-color 0.3s;
}

.card-element:focus-within {
    border-color: #667eea;
}

.error-message {
    color: #e74c3c;
    font-size: 14px;
    margin-bottom: 20px;
    min-height: 20px;
    display: none;
}

.error-message.show {
    display: block;
}

.submit-button {
    width: 100%;
    padding: 14px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.submit-button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.4);
}

.submit-button:active:not(:disabled) {
    transform: translateY(0);
}

.submit-button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.spinner {
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top: 2px solid white;
    border-radius: 50%;
    width: 20px;
    height: 20px;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.hidden {
    display: none;
}

.payment-status {
    margin-top: 20px;
    padding: 15px;
    border-radius: 8px;
    text-align: center;
    font-weight: 500;
}

.payment-status.success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.payment-status.error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.payment-status.show {
    display: block;
}