/*
 * Liquid Glass Design System
 * Inspired by Apple iOS 26 / macOS design language
 * 
 * Features:
 * - Frosted glass effects with backdrop blur
 * - Floating UI elements
 * - Pill-shaped containers
 * - Subtle luminosity and depth
 * - Dynamic transparency
 */

/* ============================================
   CSS Variables - Liquid Glass Theme
   ============================================ */

:root {
    /* Glass backgrounds */
    --glass-bg: rgba(255, 255, 255, 0.72);
    --glass-bg-light: rgba(255, 255, 255, 0.85);
    --glass-bg-dark: rgba(255, 255, 255, 0.6);
    --glass-bg-elevated: rgba(255, 255, 255, 0.9);
    
    /* Glass borders */
    --glass-border: rgba(255, 255, 255, 0.5);
    --glass-border-light: rgba(255, 255, 255, 0.8);
    --glass-border-subtle: rgba(255, 255, 255, 0.3);
    
    /* Glass shadows */
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.08);
    --glass-shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.12);
    --glass-shadow-inset: inset 0 1px 0 rgba(255, 255, 255, 0.6);
    --glass-glow: 0 0 20px rgba(255, 255, 255, 0.3);
    
    /* Blur amounts */
    --blur-sm: 10px;
    --blur-md: 20px;
    --blur-lg: 40px;
    --blur-xl: 60px;
    
    /* Primary colors with glass tints */
    --primary-glass: rgba(0, 102, 204, 0.15);
    --primary-glass-solid: rgba(0, 102, 204, 0.9);
    --success-glass: rgba(34, 197, 94, 0.15);
    --warning-glass: rgba(234, 179, 8, 0.15);
    --error-glass: rgba(239, 68, 68, 0.15);
    
    /* Teacher orange glass */
    --teacher-glass: rgba(249, 115, 22, 0.15);
    --teacher-glass-solid: rgba(249, 115, 22, 0.9);
    
    /* Text on glass */
    --text-on-glass: rgba(0, 0, 0, 0.85);
    --text-on-glass-secondary: rgba(0, 0, 0, 0.6);
    --text-on-glass-tertiary: rgba(0, 0, 0, 0.4);
    
    /* Active/Selected state */
    --glass-active: rgba(255, 255, 255, 0.95);
    --glass-active-tint: rgba(0, 102, 204, 0.1);
    
    /* Pill radius */
    --pill-radius: 100px;
    --card-radius: 24px;
    --button-radius: 16px;
    
    /* Spacing */
    --nav-padding: 12px 20px;
    --nav-gap: 4px;
    --nav-bottom-offset: 24px;
}

/* Dark mode glass */
[data-theme="dark"] {
    --glass-bg: rgba(30, 30, 40, 0.75);
    --glass-bg-light: rgba(40, 40, 55, 0.85);
    --glass-bg-dark: rgba(20, 20, 30, 0.7);
    --glass-bg-elevated: rgba(50, 50, 65, 0.9);
    
    --glass-border: rgba(255, 255, 255, 0.15);
    --glass-border-light: rgba(255, 255, 255, 0.25);
    --glass-border-subtle: rgba(255, 255, 255, 0.08);
    
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    --glass-shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.4);
    --glass-shadow-inset: inset 0 1px 0 rgba(255, 255, 255, 0.1);
    --glass-glow: 0 0 20px rgba(255, 255, 255, 0.05);
    
    --text-on-glass: rgba(255, 255, 255, 0.95);
    --text-on-glass-secondary: rgba(255, 255, 255, 0.7);
    --text-on-glass-tertiary: rgba(255, 255, 255, 0.5);
    
    --glass-active: rgba(60, 60, 75, 0.95);
    --glass-active-tint: rgba(0, 122, 255, 0.2);
}

/* ============================================
   Base Glass Mixins (as classes)
   ============================================ */

.glass {
    background: var(--glass-bg);
    backdrop-filter: blur(var(--blur-md));
    -webkit-backdrop-filter: blur(var(--blur-md));
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow), var(--glass-shadow-inset);
}

.glass-light {
    background: var(--glass-bg-light);
    backdrop-filter: blur(var(--blur-lg));
    -webkit-backdrop-filter: blur(var(--blur-lg));
    border: 1px solid var(--glass-border-light);
    box-shadow: var(--glass-shadow), var(--glass-shadow-inset);
}

.glass-elevated {
    background: var(--glass-bg-elevated);
    backdrop-filter: blur(var(--blur-xl));
    -webkit-backdrop-filter: blur(var(--blur-xl));
    border: 1px solid var(--glass-border-light);
    box-shadow: var(--glass-shadow-lg), var(--glass-shadow-inset), var(--glass-glow);
}

/* ============================================
   Floating Bottom Navigation - Liquid Glass
   ============================================ */

.glass-nav {
    position: fixed;
    bottom: var(--nav-bottom-offset);
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    gap: var(--nav-gap);
    padding: var(--nav-padding);
    z-index: 1000;
    
    /* Glass effect */
    background: var(--glass-bg);
    backdrop-filter: blur(var(--blur-lg));
    -webkit-backdrop-filter: blur(var(--blur-lg));
    
    /* Pill shape */
    border-radius: var(--pill-radius);
    
    /* Glass edges & depth */
    border: 1px solid var(--glass-border);
    box-shadow: 
        var(--glass-shadow-lg),
        var(--glass-shadow-inset),
        0 0 0 1px var(--glass-border-subtle);
    
    /* Safe area support */
    padding-bottom: max(12px, env(safe-area-inset-bottom));
}

.glass-nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    padding: 8px 16px;
    min-width: 56px;
    border-radius: 20px;
    text-decoration: none;
    color: var(--text-on-glass-secondary);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}

.glass-nav-item:hover {
    color: var(--text-on-glass);
    background: var(--glass-border-subtle);
}

.glass-nav-item.active {
    color: var(--primary-500, #0066cc);
    background: var(--glass-active);
    box-shadow: 
        0 2px 8px rgba(0, 0, 0, 0.06),
        inset 0 1px 0 rgba(255, 255, 255, 0.8);
}

/* Teacher nav active state */
.glass-nav.teacher .glass-nav-item.active {
    color: var(--teacher-primary, #f97316);
}

.glass-nav-icon {
    width: 24px;
    height: 24px;
    flex-shrink: 0;
    color: var(--text-on-glass-secondary);
    transition: transform 0.2s ease, color 0.2s ease;
}

/* SVG icon styling */
.glass-nav-icon svg {
    width: 100%;
    height: 100%;
    stroke: currentColor;
    stroke-width: 1.5;
    fill: none;
}

.glass-nav-item:hover .glass-nav-icon {
    transform: scale(1.1);
    color: var(--text-on-glass);
}

.glass-nav-item.active .glass-nav-icon {
    transform: scale(1.05);
    color: var(--primary-500, #0066cc);
}

/* Teacher nav uses orange for active */
.glass-nav.teacher .glass-nav-item.active .glass-nav-icon {
    color: var(--teacher-primary, #f97316);
}

.glass-nav-label {
    font-size: 11px;
    font-weight: 500;
    letter-spacing: 0.02em;
    white-space: nowrap;
}

/* Adjust content padding to account for floating nav */
.has-glass-nav {
    padding-bottom: calc(100px + env(safe-area-inset-bottom));
}

/* ============================================
   Glass Cards
   ============================================ */

.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(var(--blur-md));
    -webkit-backdrop-filter: blur(var(--blur-md));
    border-radius: var(--card-radius);
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow), var(--glass-shadow-inset);
    padding: 20px;
    transition: all 0.3s ease;
}

.glass-card:hover {
    box-shadow: var(--glass-shadow-lg), var(--glass-shadow-inset), var(--glass-glow);
    transform: translateY(-2px);
}

.glass-card-elevated {
    background: var(--glass-bg-elevated);
    backdrop-filter: blur(var(--blur-lg));
    -webkit-backdrop-filter: blur(var(--blur-lg));
    box-shadow: var(--glass-shadow-lg), var(--glass-shadow-inset);
}

/* ============================================
   Glass Header
   ============================================ */

.glass-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 900;
    padding: 12px 20px;
    padding-top: max(12px, env(safe-area-inset-top));
    
    background: var(--glass-bg);
    backdrop-filter: blur(var(--blur-lg));
    -webkit-backdrop-filter: blur(var(--blur-lg));
    border-bottom: 1px solid var(--glass-border-subtle);
    box-shadow: var(--glass-shadow);
}

.glass-header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 600px;
    margin: 0 auto;
}

.glass-header-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-on-glass);
}

.glass-header-logo {
    height: 32px;
    width: auto;
}

/* ============================================
   Glass Buttons
   ============================================ */

.glass-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 600;
    border-radius: var(--button-radius);
    border: none;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    
    background: var(--glass-bg-light);
    backdrop-filter: blur(var(--blur-sm));
    -webkit-backdrop-filter: blur(var(--blur-sm));
    color: var(--text-on-glass);
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow), var(--glass-shadow-inset);
}

.glass-btn:hover {
    background: var(--glass-bg-elevated);
    transform: translateY(-1px);
    box-shadow: var(--glass-shadow-lg), var(--glass-shadow-inset);
}

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

.glass-btn-primary {
    background: var(--primary-glass-solid);
    color: white;
    border: none;
    box-shadow: 
        0 4px 16px rgba(0, 102, 204, 0.3),
        var(--glass-shadow-inset);
}

.glass-btn-primary:hover {
    background: rgba(0, 102, 204, 0.95);
    box-shadow: 
        0 8px 24px rgba(0, 102, 204, 0.4),
        var(--glass-shadow-inset);
}

/* Teacher primary button */
.glass-btn-teacher {
    background: var(--teacher-glass-solid);
    color: white;
    border: none;
    box-shadow: 
        0 4px 16px rgba(249, 115, 22, 0.3),
        var(--glass-shadow-inset);
}

.glass-btn-teacher:hover {
    background: rgba(249, 115, 22, 0.95);
    box-shadow: 
        0 8px 24px rgba(249, 115, 22, 0.4),
        var(--glass-shadow-inset);
}

.glass-btn-large {
    padding: 16px 32px;
    font-size: 18px;
    border-radius: 20px;
    min-height: 56px;
}

.glass-btn-block {
    width: 100%;
}

.glass-btn-icon {
    width: 44px;
    height: 44px;
    padding: 0;
    border-radius: 50%;
}

/* ============================================
   Glass Inputs
   ============================================ */

.glass-input {
    width: 100%;
    padding: 14px 18px;
    font-size: 16px;
    color: var(--text-on-glass);
    background: var(--glass-bg-light);
    backdrop-filter: blur(var(--blur-sm));
    -webkit-backdrop-filter: blur(var(--blur-sm));
    border: 1px solid var(--glass-border);
    border-radius: 14px;
    box-shadow: var(--glass-shadow-inset);
    transition: all 0.3s ease;
}

.glass-input::placeholder {
    color: var(--text-on-glass-tertiary);
}

.glass-input:focus {
    outline: none;
    border-color: var(--primary-500, #0066cc);
    box-shadow: 
        var(--glass-shadow-inset),
        0 0 0 4px var(--primary-glass);
}

.glass-input-group {
    position: relative;
}

.glass-input-icon {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 20px;
    color: var(--text-on-glass-tertiary);
    pointer-events: none;
}

.glass-input-group .glass-input {
    padding-left: 48px;
}

[dir="rtl"] .glass-input-icon {
    left: auto;
    right: 16px;
}

[dir="rtl"] .glass-input-group .glass-input {
    padding-left: 18px;
    padding-right: 48px;
}

/* ============================================
   Glass Modal / Sheet
   ============================================ */

.glass-modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    display: flex;
    align-items: flex-end;
    justify-content: center;
    z-index: 2000;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}

.glass-modal-overlay.show {
    opacity: 1;
    pointer-events: auto;
}

.glass-modal {
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    
    background: var(--glass-bg-elevated);
    backdrop-filter: blur(var(--blur-xl));
    -webkit-backdrop-filter: blur(var(--blur-xl));
    border-radius: 28px 28px 0 0;
    border: 1px solid var(--glass-border);
    border-bottom: none;
    box-shadow: var(--glass-shadow-lg);
    
    transform: translateY(100%);
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.glass-modal-overlay.show .glass-modal {
    transform: translateY(0);
}

.glass-modal-handle {
    width: 36px;
    height: 5px;
    background: var(--glass-border);
    border-radius: 3px;
    margin: 12px auto;
}

.glass-modal-header {
    padding: 16px 20px;
    border-bottom: 1px solid var(--glass-border-subtle);
}

.glass-modal-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-on-glass);
    text-align: center;
}

.glass-modal-body {
    padding: 20px;
}

/* ============================================
   Glass Stats / Pills
   ============================================ */

.glass-pill {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    font-size: 13px;
    font-weight: 500;
    border-radius: var(--pill-radius);
    background: var(--glass-bg-light);
    backdrop-filter: blur(var(--blur-sm));
    -webkit-backdrop-filter: blur(var(--blur-sm));
    border: 1px solid var(--glass-border);
    color: var(--text-on-glass-secondary);
}

.glass-pill-primary {
    background: var(--primary-glass);
    color: var(--primary-600, #0052a3);
    border-color: rgba(0, 102, 204, 0.2);
}

.glass-pill-success {
    background: var(--success-glass);
    color: var(--success-600, #16a34a);
    border-color: rgba(34, 197, 94, 0.2);
}

.glass-pill-warning {
    background: var(--warning-glass);
    color: var(--warning-600, #ca8a04);
    border-color: rgba(234, 179, 8, 0.2);
}

.glass-pill-error {
    background: var(--error-glass);
    color: var(--error-600, #dc2626);
    border-color: rgba(239, 68, 68, 0.2);
}

/* ============================================
   Glass Hero Section
   ============================================ */

.glass-hero {
    position: relative;
    padding: 32px 24px;
    border-radius: var(--card-radius);
    overflow: hidden;
    
    background: linear-gradient(135deg, var(--primary-500) 0%, var(--primary-600) 100%);
    color: white;
}

.glass-hero.teacher {
    background: linear-gradient(135deg, var(--teacher-primary, #f97316) 0%, var(--teacher-primary-dark, #ea580c) 100%);
}

.glass-hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: 
        radial-gradient(circle at 30% 20%, rgba(255,255,255,0.2) 0%, transparent 50%),
        radial-gradient(circle at 70% 80%, rgba(255,255,255,0.1) 0%, transparent 50%);
    pointer-events: none;
}

.glass-hero-content {
    position: relative;
    z-index: 1;
}

/* ============================================
   Glass List Items
   ============================================ */

.glass-list {
    background: var(--glass-bg);
    backdrop-filter: blur(var(--blur-md));
    -webkit-backdrop-filter: blur(var(--blur-md));
    border-radius: var(--card-radius);
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    overflow: hidden;
}

.glass-list-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 18px;
    color: var(--text-on-glass);
    text-decoration: none;
    border-bottom: 1px solid var(--glass-border-subtle);
    transition: background 0.2s ease;
}

.glass-list-item:last-child {
    border-bottom: none;
}

.glass-list-item:hover {
    background: var(--glass-border-subtle);
}

.glass-list-item:active {
    background: var(--glass-border);
}

/* ============================================
   Glass Toggle Switch
   ============================================ */

.glass-toggle {
    position: relative;
    width: 52px;
    height: 32px;
}

.glass-toggle input {
    opacity: 0;
    width: 0;
    height: 0;
}

.glass-toggle-slider {
    position: absolute;
    cursor: pointer;
    inset: 0;
    background: var(--glass-bg-dark);
    backdrop-filter: blur(var(--blur-sm));
    -webkit-backdrop-filter: blur(var(--blur-sm));
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    transition: all 0.3s ease;
}

.glass-toggle-slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 2px;
    top: 2px;
    background: white;
    border-radius: 50%;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.glass-toggle input:checked + .glass-toggle-slider {
    background: var(--primary-glass-solid);
    border-color: transparent;
}

.glass-toggle input:checked + .glass-toggle-slider:before {
    transform: translateX(20px);
}

/* Teacher toggle */
.glass-toggle.teacher input:checked + .glass-toggle-slider {
    background: var(--teacher-glass-solid);
}

/* ============================================
   Animations
   ============================================ */

@keyframes glass-fade-in {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes glass-scale-in {
    from {
        opacity: 0;
        transform: scale(0.95);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.glass-animate-in {
    animation: glass-fade-in 0.4s ease forwards;
}

.glass-animate-scale {
    animation: glass-scale-in 0.3s ease forwards;
}

/* Stagger children animations */
.glass-stagger > * {
    opacity: 0;
    animation: glass-fade-in 0.4s ease forwards;
}

.glass-stagger > *:nth-child(1) { animation-delay: 0.05s; }
.glass-stagger > *:nth-child(2) { animation-delay: 0.1s; }
.glass-stagger > *:nth-child(3) { animation-delay: 0.15s; }
.glass-stagger > *:nth-child(4) { animation-delay: 0.2s; }
.glass-stagger > *:nth-child(5) { animation-delay: 0.25s; }
.glass-stagger > *:nth-child(6) { animation-delay: 0.3s; }

/* ============================================
   Responsive Adjustments
   ============================================ */

@media (max-width: 480px) {
    .glass-nav {
        --nav-bottom-offset: 16px;
        --nav-padding: 10px 14px;
        left: 16px;
        right: 16px;
        transform: none;
        width: auto;
    }
    
    .glass-nav-item {
        padding: 8px 12px;
        min-width: 48px;
    }
    
    .glass-nav-label {
        font-size: 10px;
    }
    
    .glass-card {
        border-radius: 20px;
        padding: 16px;
    }
}

/* Landscape phone - hide labels */
@media (max-height: 500px) and (orientation: landscape) {
    .glass-nav-label {
        display: none;
    }
    
    .glass-nav-item {
        padding: 10px 14px;
    }
}

/* ============================================
   Utility Classes
   ============================================ */

.glass-text-primary {
    color: var(--text-on-glass);
}

.glass-text-secondary {
    color: var(--text-on-glass-secondary);
}

.glass-text-tertiary {
    color: var(--text-on-glass-tertiary);
}

/* ============================================
   Theme Toggle SVG Icons
   ============================================ */

#theme-toggle {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

#theme-toggle svg {
    transition: transform 0.3s ease, opacity 0.3s ease;
}

#theme-toggle:hover svg {
    transform: rotate(15deg);
}

/* Auto-hide/show based on theme */
[data-theme="dark"] #theme-toggle .icon-moon {
    display: none !important;
}

[data-theme="dark"] #theme-toggle .icon-sun {
    display: block !important;
}

[data-theme="light"] #theme-toggle .icon-moon,
:root:not([data-theme="dark"]) #theme-toggle .icon-moon {
    display: block !important;
}

[data-theme="light"] #theme-toggle .icon-sun,
:root:not([data-theme="dark"]) #theme-toggle .icon-sun {
    display: none !important;
}

/* ============================================
   SVG Icon System
   ============================================ */

.svg-icon {
    width: 24px;
    height: 24px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.svg-icon svg {
    width: 100%;
    height: 100%;
    stroke: currentColor;
    stroke-width: 1.5;
    stroke-linecap: round;
    stroke-linejoin: round;
    fill: none;
}

.svg-icon-sm {
    width: 16px;
    height: 16px;
}

.svg-icon-md {
    width: 20px;
    height: 20px;
}

.svg-icon-lg {
    width: 32px;
    height: 32px;
}

.svg-icon-xl {
    width: 48px;
    height: 48px;
}

.svg-icon-2xl {
    width: 64px;
    height: 64px;
}

/* Colored icons */
.svg-icon-success { color: var(--success-500, #22c55e); }
.svg-icon-error { color: var(--error-500, #ef4444); }
.svg-icon-warning { color: var(--warning-500, #f59e0b); }
.svg-icon-info { color: var(--primary-500, #0066cc); }
.svg-icon-muted { color: var(--text-on-glass-tertiary); }

.glass-bg-tint-primary {
    background: var(--primary-glass);
}

.glass-bg-tint-teacher {
    background: var(--teacher-glass);
}

.glass-divider {
    height: 1px;
    background: var(--glass-border-subtle);
    margin: 16px 0;
}