/* Reset y estilos base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 40px;
    padding: 30px 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    font-weight: 700;
}

header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* Formulario */
.billing-form {
    background: white;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    margin-bottom: 20px;
}

.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #2d3748;
    font-size: 1rem;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background-color: #fff;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.form-group input::placeholder {
    color: #a0aec0;
}

/* Campos de documento */
.document-fields {
    background-color: #f7fafc;
    padding: 25px;
    border-radius: 8px;
    border-left: 4px solid #667eea;
    margin-top: 20px;
}

/* Mensajes de error */
.error-message {
    color: #e53e3e;
    font-size: 0.875rem;
    margin-top: 5px;
    display: block;
}

/* Botones */
.form-actions {
    margin-top: 30px;
    text-align: center;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 14px 32px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 6px rgba(102, 126, 234, 0.2);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(102, 126, 234, 0.3);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* Mensaje de éxito */
.success-message {
    background: linear-gradient(135deg, #48bb78 0%, #38a169 100%);
    color: white;
    padding: 30px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 4px 6px rgba(72, 187, 120, 0.2);
}

.success-message h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    header {
        padding: 20px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .billing-form {
        padding: 25px;
    }
    
    .document-fields {
        padding: 20px;
    }
}

/* Animaciones */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.document-fields {
    animation: fadeIn 0.3s ease-out;
}

/* Estados de validación */
.form-group input.valid {
    border-color: #48bb78;
}

.form-group input.invalid {
    border-color: #e53e3e;
}

/* Loading state */
.btn-primary.loading {
    position: relative;
    color: transparent;
}

.btn-primary.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 20px;
    height: 20px;
    border: 2px solid transparent;
    border-top: 2px solid white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: translate(-50%, -50%) rotate(0deg); }
    100% { transform: translate(-50%, -50%) rotate(360deg); }
}