/* ============================================
   NEON LAB DESIGN SYSTEM - Explorers Hub
   Dark Mode Theme for Young Explorers
   ============================================ */

/* ============================================
   CSS CUSTOM PROPERTIES (Design Tokens)
   ============================================ */
:root {
    /* Core Colors */
    --color-background: #121212;
    --color-surface: #1e1e1e;
    --color-surface-elevated: #2a2a2a;
    --color-text-primary: #e0e0e0;
    --color-text-secondary: #a0a0a0;
    --color-text-muted: #707070;

    /* Neon Accent Colors */
    --neon-blue: #54a0ff;
    --neon-blue-glow: rgba(84, 160, 255, 0.4);
    --neon-orange: #ff9f43;
    --neon-orange-glow: rgba(255, 159, 67, 0.4);
    --neon-green: #2ed573;
    --neon-green-glow: rgba(46, 213, 115, 0.4);
    --neon-purple: #a55eea;
    --neon-purple-glow: rgba(165, 94, 234, 0.4);

    /* Typography */
    --font-primary: 'Comic Sans MS', 'Arial Rounded MT Bold', 'Nunito', sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.25rem;
    --font-size-xl: 1.5rem;
    --font-size-2xl: 2rem;
    --font-size-3xl: 2.5rem;
    --font-size-hero: 3.5rem;

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-pill: 9999px;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
    --shadow-glow-blue: 0 0 20px var(--neon-blue-glow), 0 0 40px var(--neon-blue-glow);
    --shadow-glow-orange: 0 0 20px var(--neon-orange-glow), 0 0 40px var(--neon-orange-glow);
    --shadow-glow-green: 0 0 20px var(--neon-green-glow), 0 0 40px var(--neon-green-glow);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 400ms ease;

    /* Layout */
    --nav-height: 64px;
    --container-max: 1200px;
    --card-min-height: 180px;
}

/* ============================================
   RESET & BASE STYLES
   ============================================ */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

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

/* Animated Background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background:
        radial-gradient(ellipse at 20% 20%, rgba(84, 160, 255, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 80%, rgba(255, 159, 67, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 50%, rgba(46, 213, 115, 0.05) 0%, transparent 60%);
    pointer-events: none;
    z-index: -1;
}

a {
    color: inherit;
    text-decoration: none;
}

ul,
ol {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* ============================================
   STICKY NAVIGATION BAR
   ============================================ */
.navbar {
    position: sticky;
    top: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-md) var(--space-xl);
    background: linear-gradient(180deg, rgba(30, 30, 30, 0.98) 0%, rgba(30, 30, 30, 0.95) 100%);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    min-height: var(--nav-height);
}

.navbar__brand {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    cursor: pointer;
    transition: transform var(--transition-fast);
}

.navbar__brand:hover {
    transform: scale(1.02);
}

.navbar__logo {
    font-size: var(--font-size-xl);
}

.navbar__title {
    font-size: var(--font-size-lg);
    font-weight: 700;
    background: linear-gradient(135deg, var(--neon-blue), var(--neon-green));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.navbar__breadcrumbs {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

.breadcrumb {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-xs) var(--space-md);
    background: var(--color-surface);
    border-radius: var(--radius-pill);
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--transition-base);
    border: 1px solid transparent;
    min-height: 36px;
}

.breadcrumb:hover {
    background: var(--color-surface-elevated);
    color: var(--color-text-primary);
    border-color: var(--neon-blue);
}

.breadcrumb--active {
    background: var(--neon-blue);
    color: var(--color-background);
    font-weight: 600;
    cursor: default;
}

.breadcrumb--active:hover {
    background: var(--neon-blue);
    border-color: transparent;
}

.breadcrumb__separator {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

/* ============================================
   MAIN CONTAINER
   ============================================ */
.main-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: var(--space-xl);
    min-height: calc(100vh - var(--nav-height));
}

/* ============================================
   VIEW SECTIONS
   ============================================ */
.view {
    display: none;
    animation: fadeIn var(--transition-base) ease;
}

.view--active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* View Header */
.view__header {
    text-align: center;
    margin-bottom: var(--space-2xl);
}

.view__title {
    font-size: var(--font-size-hero);
    font-weight: 800;
    margin-bottom: var(--space-md);
    background: linear-gradient(135deg, var(--neon-blue) 0%, var(--neon-green) 50%, var(--neon-orange) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-shadow: 0 0 60px var(--neon-blue-glow);
}

.view__subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* ============================================
   SELECTION GRID (Age Groups & Subjects)
   ============================================ */
.selection-grid {
    display: grid;
    gap: var(--space-lg);
    justify-content: center;
}

/* Age Selection - Large Cards */
.selection-grid--ages {
    grid-template-columns: repeat(auto-fit, minmax(180px, 220px));
}

/* Subject Selection */
.selection-grid--subjects {
    grid-template-columns: repeat(auto-fit, minmax(160px, 200px));
}

/* ============================================
   SELECTION CARDS (Age & Subject Buttons)
   ============================================ */
.selection-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--space-md);
    padding: var(--space-xl) var(--space-lg);
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-base);
    min-height: 160px;
    text-align: center;
}

.selection-card:hover {
    transform: translateY(-6px) scale(1.02);
    border-color: var(--neon-blue);
    box-shadow: var(--shadow-glow-blue);
}

.selection-card--science:hover {
    border-color: var(--neon-blue);
    box-shadow: var(--shadow-glow-blue);
}

.selection-card--math:hover {
    border-color: var(--neon-orange);
    box-shadow: var(--shadow-glow-orange);
}

.selection-card--arts:hover,
.selection-card--general:hover {
    border-color: var(--neon-green);
    box-shadow: var(--shadow-glow-green);
}

.selection-card__icon {
    font-size: 3rem;
    line-height: 1;
}

.selection-card__label {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--color-text-primary);
}

.selection-card__sublabel {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

/* ============================================
   APP GALLERY GRID
   ============================================ */
.gallery-section {
    margin-bottom: var(--space-3xl);
}

.gallery-section__header {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
    padding-bottom: var(--space-sm);
    border-bottom: 2px solid var(--color-surface-elevated);
}

.gallery-section__icon {
    font-size: var(--font-size-xl);
}

.gallery-section__title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text-primary);
}

.gallery-section__count {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    padding: var(--space-xs) var(--space-sm);
    background: var(--color-surface);
    border-radius: var(--radius-pill);
}

/* App Cards Grid */
.app-grid {
    display: grid;
    gap: var(--space-lg);
    grid-template-columns: 1fr;
}

@media (min-width: 600px) {
    .app-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 900px) {
    .app-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (min-width: 1200px) {
    .app-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* ============================================
   APP CARDS
   ============================================ */
.app-card {
    display: flex;
    flex-direction: column;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-base);
    min-height: var(--card-min-height);
}

.app-card:hover {
    transform: translateY(-8px) scale(1.03);
    border-color: var(--neon-blue);
    box-shadow: var(--shadow-glow-blue);
}

.app-card--science:hover {
    border-color: var(--neon-blue);
    box-shadow: var(--shadow-glow-blue);
}

.app-card--math:hover {
    border-color: var(--neon-orange);
    box-shadow: var(--shadow-glow-orange);
}

.app-card--arts:hover,
.app-card--general:hover {
    border-color: var(--neon-green);
    box-shadow: var(--shadow-glow-green);
}

.app-card__header {
    padding: var(--space-lg);
    background: linear-gradient(135deg, rgba(84, 160, 255, 0.15) 0%, rgba(46, 213, 115, 0.1) 100%);
    text-align: center;
}

.app-card--science .app-card__header {
    background: linear-gradient(135deg, rgba(84, 160, 255, 0.2) 0%, rgba(84, 160, 255, 0.05) 100%);
}

.app-card--math .app-card__header {
    background: linear-gradient(135deg, rgba(255, 159, 67, 0.2) 0%, rgba(255, 159, 67, 0.05) 100%);
}

.app-card--arts .app-card__header,
.app-card--general .app-card__header {
    background: linear-gradient(135deg, rgba(46, 213, 115, 0.2) 0%, rgba(46, 213, 115, 0.05) 100%);
}

.app-card__icon {
    font-size: 2.5rem;
    margin-bottom: var(--space-sm);
}

.app-card__title {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--color-text-primary);
}

.app-card__body {
    flex: 1;
    padding: var(--space-lg);
    display: flex;
    flex-direction: column;
}

.app-card__description {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    line-height: 1.5;
    flex: 1;
}

.app-card__meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: var(--space-md);
    padding-top: var(--space-md);
    border-top: 1px solid var(--color-surface-elevated);
}

.app-card__category {
    font-size: var(--font-size-xs);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--color-text-muted);
}

.app-card__launch {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: var(--font-size-sm);
    color: var(--neon-blue);
    font-weight: 600;
}

.app-card--math .app-card__launch {
    color: var(--neon-orange);
}

.app-card--arts .app-card__launch,
.app-card--general .app-card__launch {
    color: var(--neon-green);
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    font-family: var(--font-primary);
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--color-text-primary);
    background: var(--color-surface);
    border: 2px solid transparent;
    border-radius: var(--radius-pill);
    cursor: pointer;
    transition: all var(--transition-base);
    min-height: 44px;
    text-decoration: none;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn--primary {
    background: linear-gradient(135deg, var(--neon-blue) 0%, #4a90e5 100%);
    color: var(--color-background);
}

.btn--primary:hover {
    box-shadow: var(--shadow-glow-blue);
}

.btn--secondary {
    background: transparent;
    border-color: var(--neon-blue);
    color: var(--neon-blue);
}

.btn--secondary:hover {
    background: var(--neon-blue);
    color: var(--color-background);
}

.btn--back {
    background: var(--color-surface-elevated);
    color: var(--color-text-secondary);
}

.btn--back:hover {
    background: var(--color-surface);
    color: var(--color-text-primary);
}

/* ============================================
   EMPTY STATE
   ============================================ */
.empty-state {
    text-align: center;
    padding: var(--space-3xl) var(--space-xl);
}

.empty-state__icon {
    font-size: 4rem;
    margin-bottom: var(--space-lg);
    opacity: 0.5;
}

.empty-state__title {
    font-size: var(--font-size-xl);
    color: var(--color-text-primary);
    margin-bottom: var(--space-md);
}

.empty-state__text {
    font-size: var(--font-size-base);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-xl);
}

/* ============================================
   RESPONSIVE ADJUSTMENTS
   ============================================ */
@media (max-width: 600px) {
    :root {
        --font-size-hero: 2.5rem;
        --space-xl: 1.5rem;
        --space-2xl: 2rem;
    }

    .navbar {
        flex-direction: column;
        gap: var(--space-md);
        padding: var(--space-md);
    }

    .navbar__breadcrumbs {
        justify-content: center;
    }

    .selection-grid--ages {
        grid-template-columns: 1fr;
    }

    .selection-grid--subjects {
        grid-template-columns: repeat(2, 1fr);
    }

    .view__title {
        font-size: var(--font-size-2xl);
    }

    .selection-card {
        min-height: 120px;
        padding: var(--space-lg);
    }
}

/* ============================================
   ANIMATIONS & MICRO-INTERACTIONS
   ============================================ */
@keyframes pulse {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.7;
    }
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-10px);
    }
}

.animate-pulse {
    animation: pulse 2s ease-in-out infinite;
}

.animate-float {
    animation: float 3s ease-in-out infinite;
}

/* Loading State */
.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-3xl);
}

.loading__spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--color-surface-elevated);
    border-top-color: var(--neon-blue);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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