:root {
    /* Color Palette - Premium Slate/Blue */
    --bg-color: #0F172A;
    --surface-color: rgba(30, 41, 59, 0.7);
    --surface-hover: rgba(51, 65, 85, 0.9);
    --surface-border: rgba(255, 255, 255, 0.1);
    
    --text-primary: #F8FAFC;
    --text-secondary: #94A3B8;
    
    --primary-color: #3B82F6;
    --primary-hover: #2563EB;
    --accent-color: #10B981;
    
    /* Spacing & Radii */
    --radius-lg: 16px;
    --radius-md: 12px;
    --radius-sm: 8px;
    
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;

    /* Shadows & Transitions */
    --shadow-soft: 0 10px 25px -5px rgba(0, 0, 0, 0.3);
    --transition-fast: 0.2s ease;
    --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
    /* Soft gradient background */
    background-image: 
        radial-gradient(at 0% 0%, rgba(59, 130, 246, 0.15) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(16, 185, 129, 0.1) 0px, transparent 50%);
    background-attachment: fixed;
    min-height: 100vh;
}

/* Layout */
.app-container {
    max-width: 480px; /* Mobile optimal width */
    margin: 0 auto;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
.app-header {
    padding: var(--spacing-xl) var(--spacing-lg) var(--spacing-md);
    position: sticky;
    top: 0;
    z-index: 10;
    background: linear-gradient(to bottom, var(--bg-color) 60%, transparent);
}

.brand-title {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    margin-bottom: var(--spacing-xs);
    background: linear-gradient(135deg, #fff 0%, #94A3B8 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.brand-subtitle {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 400;
}

/* Main Content */
.main-content {
    flex: 1;
    padding: 0 var(--spacing-lg) var(--spacing-xl);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

/* Glassmorphism Cards */
.service-card {
    background: var(--surface-color);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    transition: var(--transition-smooth);
    box-shadow: var(--shadow-soft);
}

.service-card:hover, .service-card:active {
    background: var(--surface-hover);
    transform: translateY(-2px);
    border-color: rgba(255, 255, 255, 0.2);
}

.service-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.service-name {
    font-size: 1.1rem;
    font-weight: 600;
}

.service-duration {
    font-size: 0.85rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 4px;
}

.service-action {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: var(--spacing-sm);
}

.service-price {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--accent-color);
}

.btn-select {
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-sm);
    padding: 8px 16px;
    font-size: 0.9rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-fast);
}

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

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.fade-in {
    animation: fadeIn 0.5s cubic-bezier(0.4, 0, 0.2, 1) forwards;
    opacity: 0;
}

/* Loader */
.loader-container {
    display: none; /* Hidden by default */
    justify-content: center;
    align-items: center;
    padding: var(--spacing-xl) 0;
}

.spinner {
    width: 32px;
    height: 32px;
    border: 3px solid var(--surface-border);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Calendar & Timeslots */
.calendar-section {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.section-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.date-scroller {
    display: flex;
    overflow-x: auto;
    gap: var(--spacing-sm);
    padding-bottom: var(--spacing-sm);
    -ms-overflow-style: none;
    scrollbar-width: none;
}
.date-scroller::-webkit-scrollbar {
    display: none;
}

.date-card {
    flex: 0 0 calc(25% - var(--spacing-sm));
    min-width: 70px;
    background: var(--surface-color);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-md) var(--spacing-sm);
    display: flex;
    flex-direction: column;
    align-items: center;
    cursor: pointer;
    transition: var(--transition-fast);
}

.date-card.active {
    background: var(--primary-color);
    border-color: var(--primary-hover);
}

.date-day {
    font-size: 0.8rem;
    text-transform: uppercase;
    color: var(--text-secondary);
}
.date-card.active .date-day {
    color: rgba(255, 255, 255, 0.8);
}

.date-number {
    font-size: 1.3rem;
    font-weight: 700;
}

.time-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
    gap: var(--spacing-sm);
}

.time-slot {
    background: var(--surface-color);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-sm);
    padding: 12px 0;
    text-align: center;
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    transition: var(--transition-fast);
}

.time-slot:hover {
    background: var(--surface-hover);
}

.time-slot.active {
    background: var(--primary-color);
    border-color: var(--primary-hover);
    color: white;
}

.time-slot.occupied {
    background: rgba(30, 41, 59, 0.4);
    border-color: rgba(255, 255, 255, 0.05);
    color: var(--text-secondary);
    opacity: 0.8;
}

.time-slot.occupied:hover {
    background: rgba(51, 65, 85, 0.8);
    border-color: rgba(255, 255, 255, 0.2);
    color: var(--text-primary);
}

.waitlist-icon {
    font-size: 0.8em;
    margin-left: 4px;
}

/* Utils */
.fade-out {
    animation: fadeOut 0.4s forwards;
}

@keyframes fadeOut {
    to { opacity: 0; transform: translateY(-10px); }
}

/* Summary View */
.summary-card {
    background: var(--surface-color);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: var(--shadow-soft);
    margin-bottom: var(--spacing-xl);
}

.summary-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: var(--spacing-sm);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.summary-row:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.summary-label {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.summary-value {
    font-weight: 600;
    font-size: 1.05rem;
    color: var(--text-primary);
}

.summary-value.total {
    color: var(--accent-color);
    font-size: 1.25rem;
}

.btn-whatsapp {
    background-color: #25D366;
    color: #ffffff;
    border: none;
    border-radius: var(--radius-sm);
    padding: 14px 24px;
    font-size: 1.1rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    width: 100%;
    box-shadow: 0 4px 14px rgba(37, 211, 102, 0.4);
}

.btn-whatsapp:hover {
    background-color: #128C7E;
    transform: translateY(-2px);
}




/* CALENDAR GRID */
.calendar-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 4px;
    text-align: center;
    background: var(--surface-color);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
}

.weekday {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    font-weight: 600;
    margin-bottom: 8px;
}

.calendar-day {
    padding: 10px 0;
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-color);
    cursor: pointer;
    transition: all 0.2s ease;
    background-color: transparent;
}

.calendar-day:not(.disabled):not(.empty):hover {
    background-color: rgba(255, 255, 255, 0.05);
}

.calendar-day.selected {
    background-color: var(--primary-color);
    color: white;
    font-weight: 600;
}

.calendar-day.disabled {
    color: var(--text-muted);
    cursor: not-allowed;
    opacity: 0.5;
}

.calendar-day.empty {
    visibility: hidden;
}

.month-nav {
    background: none;
    border: none;
    color: var(--primary-color);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 4px 12px;
    border-radius: var(--radius-sm);
    transition: background-color 0.2s;
}

.month-nav:hover {
    background-color: rgba(255,255,255,0.05);
}