/* ============================================
   CSS Reset & Base Styles
   ============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Palette */
    --primary-color: #4F46E5;
    --primary-hover: #4338CA;
    --secondary-color: #6B7280;
    --success-color: #10B981;
    --error-color: #EF4444;
    --background: #F9FAFB;
    --surface: #FFFFFF;
    --text-primary: #111827;
    --text-secondary: #6B7280;
    --border: #E5E7EB;
    --shadow: rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    
    /* Transitions */
    --transition: all 0.3s ease;
}

body {
    font-family: var(--font-family);
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* ============================================
   Container & Layout
   ============================================ */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg);
}

/* ============================================
   Header
   ============================================ */
.header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-lg) 0;
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: var(--spacing-xs);
}

.subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
}

/* ============================================
   Date Selector Section
   ============================================ */
.date-selector {
    background: var(--surface);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: 0 1px 3px var(--shadow);
    margin-bottom: var(--spacing-lg);
}

.date-selector h2 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.date-inputs {
    display: flex;
    gap: var(--spacing-md);
    align-items: flex-end;
    flex-wrap: wrap;
}

.input-group {
    flex: 1;
    min-width: 200px;
}

.input-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
    color: var(--text-secondary);
}

.input-group input[type="date"] {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: var(--transition);
}

.input-group input[type="date"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

/* ============================================
   Buttons
   ============================================ */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(79, 70, 229, 0.3);
}

.btn-secondary {
    background: var(--secondary-color);
    color: white;
}

.btn-secondary:hover {
    background: #4B5563;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* ============================================
   Slots Section
   ============================================ */
.slots-section {
    margin-top: var(--spacing-lg);
}

.slots-section h2 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.slots-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.date-group {
    background: var(--surface);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: 0 1px 3px var(--shadow);
}

.date-header {
    font-size: 1.25rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--border);
}

.slots-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-md);
}

.slot-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    color: white;
    transition: var(--transition);
}

.slot-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 20px rgba(102, 126, 234, 0.4);
}

.slot-time {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.btn-book {
    width: 100%;
    background: white;
    color: var(--primary-color);
    padding: 0.5rem 1rem;
}

.btn-book:hover {
    background: rgba(255, 255, 255, 0.9);
}

.no-slots {
    text-align: center;
    padding: var(--spacing-xl);
    background: var(--surface);
    border-radius: var(--radius-lg);
    color: var(--text-secondary);
}

/* ============================================
   Loading Indicator
   ============================================ */
.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-xl);
    gap: var(--spacing-md);
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ============================================
   Modal
   ============================================ */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    overflow-y: auto;
}

.modal-content {
    background-color: var(--surface);
    margin: 5% auto;
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    max-width: 600px;
    position: relative;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.close {
    position: absolute;
    right: var(--spacing-md);
    top: var(--spacing-md);
    font-size: 2rem;
    font-weight: bold;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
}

.close:hover {
    color: var(--text-primary);
}

.modal-content h2 {
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.selected-slot-info {
    background: var(--background);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-lg);
}

.selected-slot-info p {
    margin-bottom: var(--spacing-xs);
}

/* ============================================
   Form Styles
   ============================================ */
.form-group {
    margin-bottom: var(--spacing-md);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
    color: var(--text-secondary);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-family: var(--font-family);
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

.form-actions {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.form-actions .btn {
    flex: 1;
}

.booking-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: var(--spacing-lg);
    gap: var(--spacing-md);
}

/* ============================================
   Confirmation Modal
   ============================================ */
.modal-content.confirmation {
    text-align: center;
}

.success-icon {
    width: 80px;
    height: 80px;
    background: var(--success-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    margin: 0 auto var(--spacing-md);
    animation: scaleIn 0.5s ease;
}

@keyframes scaleIn {
    from {
        transform: scale(0);
    }
    to {
        transform: scale(1);
    }
}

.confirmation-details {
    background: var(--background);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    margin: var(--spacing-lg) 0;
    text-align: left;
}

.confirmation-details p {
    margin-bottom: var(--spacing-sm);
}

.confirmation-note {
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* ============================================
   Error Message
   ============================================ */
.error-message {
    position: fixed;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    background: var(--error-color);
    color: white;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    box-shadow: 0 4px 12px rgba(239, 68, 68, 0.3);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    max-width: 400px;
    z-index: 2000;
    animation: slideInRight 0.3s ease;
}

@keyframes slideInRight {
    from {
        transform: translateX(100%);
    }
    to {
        transform: translateX(0);
    }
}

.error-icon {
    font-size: 1.5rem;
}

.close-error {
    background: none;
    border: none;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
    margin-left: auto;
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }
    
    .date-inputs {
        flex-direction: column;
    }
    
    .input-group {
        width: 100%;
    }
    
    .slots-grid {
        grid-template-columns: 1fr;
    }
    
    .modal-content {
        margin: 10% 1rem;
        padding: var(--spacing-lg);
    }
    
    .form-actions {
        flex-direction: column;
    }
    
    .error-message {
        left: var(--spacing-md);
        right: var(--spacing-md);
        max-width: none;
    }
}