/**
 * 100일 바이브코딩 갤러리 - 메인 스타일시트
 * Requirements: 1.4, 8.1, 8.2, 8.3, 8.4
 */

/* =====================================================
   CSS Variables & Theme
   ===================================================== */
:root {
    /* Colors - Light Theme */
    --color-bg: #ffffff;
    --color-bg-secondary: #f8fafc;
    --color-bg-tertiary: #f1f5f9;
    --color-text: #1e293b;
    --color-text-secondary: #64748b;
    --color-text-muted: #94a3b8;
    --color-border: #e2e8f0;
    --color-primary: #6366f1;
    --color-primary-hover: #4f46e5;
    --color-primary-light: #eef2ff;
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-error: #ef4444;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    
    /* Typography */
    --font-sans: 'Inter', 'Noto Sans KR', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'Fira Code', 'Consolas', monospace;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;
    
    /* Layout */
    --container-max: 1280px;
    --header-height: 64px;
}

/* Dark Theme */
[data-theme="dark"] {
    --color-bg: #0f172a;
    --color-bg-secondary: #1e293b;
    --color-bg-tertiary: #334155;
    --color-text: #f1f5f9;
    --color-text-secondary: #94a3b8;
    --color-text-muted: #64748b;
    --color-border: #334155;
    --color-primary-light: #312e81;
}


/* =====================================================
   Reset & Base
   ===================================================== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

main {
    flex: 1;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-hover);
}

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

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

ul, ol {
    list-style: none;
}

/* Accessibility */
.skip-link {
    position: absolute;
    top: -100%;
    left: 0;
    background: var(--color-primary);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    z-index: 1000;
    transition: top var(--transition-fast);
}

.skip-link:focus {
    top: 0;
}

/* =====================================================
   Layout
   ===================================================== */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
    .container {
        padding: 0 var(--spacing-xl);
    }
}

/* =====================================================
   Header
   ===================================================== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    height: var(--header-height);
    backdrop-filter: blur(8px);
    background: rgba(var(--color-bg), 0.9);
}

.site-header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-text);
}

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

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

.main-nav ul {
    display: flex;
    gap: var(--spacing-lg);
}

.main-nav a {
    color: var(--color-text-secondary);
    font-weight: 500;
    padding: var(--spacing-sm) 0;
    position: relative;
}

.main-nav a:hover,
.main-nav a[aria-current="page"] {
    color: var(--color-primary);
}

.main-nav a[aria-current="page"]::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--color-primary);
    border-radius: var(--radius-full);
}

.header-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color var(--transition-fast);
}

.theme-toggle:hover {
    background: var(--color-bg-secondary);
}

.theme-icon-dark { display: none; }
[data-theme="dark"] .theme-icon-light { display: none; }
[data-theme="dark"] .theme-icon-dark { display: block; }

.mobile-menu-toggle {
    display: none;
    width: 40px;
    height: 40px;
    align-items: center;
    justify-content: center;
}

.hamburger {
    width: 20px;
    height: 2px;
    background: var(--color-text);
    position: relative;
}

.hamburger::before,
.hamburger::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    background: inherit;
    left: 0;
}

.hamburger::before { top: -6px; }
.hamburger::after { top: 6px; }

@media (max-width: 767px) {
    .main-nav { display: none; }
    .mobile-menu-toggle { display: flex; }
}

/* Mobile Navigation */
.mobile-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md);
    z-index: 99;
}

.mobile-nav ul {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.mobile-nav a {
    display: block;
    padding: var(--spacing-sm) var(--spacing-md);
    color: var(--color-text);
    border-radius: var(--radius-md);
}

.mobile-nav a:hover {
    background: var(--color-bg-secondary);
}


/* =====================================================
   Footer
   ===================================================== */
.site-footer {
    background: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
    margin-top: var(--spacing-2xl);
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-brand .logo-icon {
    font-size: 2rem;
}

.footer-brand .logo-text {
    font-size: 1.25rem;
    font-weight: 700;
}

.footer-description {
    color: var(--color-text-secondary);
    margin-top: var(--spacing-sm);
}

.footer-links h4,
.footer-social h4 {
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-md);
}

.footer-links ul,
.footer-social ul {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.footer-links a,
.footer-social a {
    color: var(--color-text-secondary);
}

.footer-links a:hover,
.footer-social a:hover {
    color: var(--color-primary);
}

.footer-bottom {
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
    text-align: center;
    color: var(--color-text-muted);
    font-size: 0.875rem;
}

@media (max-width: 767px) {
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

/* =====================================================
   Gallery Grid
   ===================================================== */
.gallery-section {
    padding: var(--spacing-2xl) 0;
}

.gallery-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.gallery-title {
    font-size: 1.5rem;
    font-weight: 700;
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

/* =====================================================
   App Card
   ===================================================== */
.app-card {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.app-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.app-card-image {
    aspect-ratio: 16 / 10;
    overflow: hidden;
    background: var(--color-bg-tertiary);
    position: relative;
}

.app-card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.app-card:hover .app-card-image img {
    transform: scale(1.05);
}

.app-card-day {
    position: absolute;
    top: var(--spacing-sm);
    left: var(--spacing-sm);
    background: var(--color-primary);
    color: white;
    font-size: 0.75rem;
    font-weight: 600;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
}

.app-card-content {
    padding: var(--spacing-md);
}

.app-card-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.app-card-title a {
    color: inherit;
}

.app-card-title a:hover {
    color: var(--color-primary);
}

.app-card-description {
    color: var(--color-text-secondary);
    font-size: 0.875rem;
    line-height: 1.5;
    margin-bottom: var(--spacing-md);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.app-card-tech {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

/* =====================================================
   Tech Stack Badge
   ===================================================== */
.tech-badge {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--color-bg-tertiary);
    color: var(--color-text-secondary);
    font-size: 0.75rem;
    font-weight: 500;
    border-radius: var(--radius-full);
    transition: background-color var(--transition-fast);
}

.tech-badge:hover {
    background: var(--color-primary-light);
    color: var(--color-primary);
}


/* =====================================================
   Day Counter & Progress
   ===================================================== */
.challenge-status {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-hover) 100%);
    color: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    margin-bottom: var(--spacing-xl);
    text-align: center;
}

.challenge-status-title {
    font-size: 0.875rem;
    font-weight: 500;
    opacity: 0.9;
    margin-bottom: var(--spacing-sm);
}

.challenge-day {
    font-size: 3rem;
    font-weight: 700;
    line-height: 1;
    margin-bottom: var(--spacing-sm);
}

.challenge-day-label {
    font-size: 1rem;
    opacity: 0.9;
}

.progress-bar {
    background: rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-full);
    height: 8px;
    margin-top: var(--spacing-md);
    overflow: hidden;
}

.progress-bar-fill {
    background: white;
    height: 100%;
    border-radius: var(--radius-full);
    transition: width var(--transition-slow);
}

.progress-text {
    font-size: 0.875rem;
    margin-top: var(--spacing-sm);
    opacity: 0.9;
}

/* =====================================================
   Search & Filter
   ===================================================== */
.filter-section {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
}

.search-box {
    flex: 1;
    min-width: 200px;
    position: relative;
}

.search-input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    padding-left: 2.5rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-bg);
    color: var(--color-text);
    font-size: 1rem;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.search-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

.search-icon {
    position: absolute;
    left: var(--spacing-md);
    top: 50%;
    transform: translateY(-50%);
    color: var(--color-text-muted);
}

.filter-dropdown {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-bg);
    color: var(--color-text);
    font-size: 1rem;
    cursor: pointer;
    min-width: 150px;
}

.filter-dropdown:focus {
    outline: none;
    border-color: var(--color-primary);
}

/* =====================================================
   Detail Page
   ===================================================== */
.app-detail {
    padding: var(--spacing-2xl) 0;
}

.app-detail-header {
    margin-bottom: var(--spacing-xl);
}

.app-detail-day {
    display: inline-block;
    background: var(--color-primary);
    color: white;
    font-size: 0.875rem;
    font-weight: 600;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    margin-bottom: var(--spacing-md);
}

.app-detail-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.app-detail-meta {
    display: flex;
    gap: var(--spacing-lg);
    color: var(--color-text-secondary);
    font-size: 0.875rem;
    margin-bottom: var(--spacing-md);
}

.app-detail-tech {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.app-detail-actions {
    display: flex;
    gap: var(--spacing-md);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-weight: 500;
    font-size: 1rem;
    transition: all var(--transition-fast);
}

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

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

.btn-secondary {
    background: var(--color-bg-secondary);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-bg-tertiary);
}

.btn-disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* =====================================================
   Screenshot Gallery
   ===================================================== */
.screenshot-gallery {
    margin-bottom: var(--spacing-xl);
}

.screenshot-main {
    aspect-ratio: 16 / 10;
    border-radius: var(--radius-lg);
    overflow: hidden;
    background: var(--color-bg-tertiary);
    margin-bottom: var(--spacing-md);
}

.screenshot-main img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    cursor: zoom-in;
}

.screenshot-thumbnails {
    display: flex;
    gap: var(--spacing-sm);
    overflow-x: auto;
    padding-bottom: var(--spacing-sm);
}

.screenshot-thumb {
    flex-shrink: 0;
    width: 100px;
    aspect-ratio: 16 / 10;
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 2px solid transparent;
    cursor: pointer;
    transition: border-color var(--transition-fast);
}

.screenshot-thumb.active,
.screenshot-thumb:hover {
    border-color: var(--color-primary);
}

.screenshot-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}


/* =====================================================
   Lightbox
   ===================================================== */
.lightbox {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.9);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.lightbox.active {
    opacity: 1;
    visibility: visible;
}

.lightbox-content {
    max-width: 90vw;
    max-height: 90vh;
}

.lightbox-content img {
    max-width: 100%;
    max-height: 90vh;
    object-fit: contain;
}

.lightbox-close {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    color: white;
    font-size: 2rem;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-full);
    transition: background-color var(--transition-fast);
}

.lightbox-close:hover {
    background: rgba(255, 255, 255, 0.1);
}

.lightbox-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    color: white;
    font-size: 2rem;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-full);
    transition: background-color var(--transition-fast);
}

.lightbox-nav:hover {
    background: rgba(255, 255, 255, 0.1);
}

.lightbox-prev { left: var(--spacing-md); }
.lightbox-next { right: var(--spacing-md); }

/* =====================================================
   Skeleton Loading
   ===================================================== */
.skeleton {
    background: linear-gradient(90deg, var(--color-bg-secondary) 25%, var(--color-bg-tertiary) 50%, var(--color-bg-secondary) 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite;
    border-radius: var(--radius-md);
}

@keyframes skeleton-loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

.skeleton-card {
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.skeleton-image {
    aspect-ratio: 16 / 10;
}

.skeleton-text {
    height: 1rem;
    margin-bottom: var(--spacing-sm);
}

.skeleton-text-sm {
    height: 0.75rem;
    width: 60%;
}

/* =====================================================
   Empty State
   ===================================================== */
.empty-state {
    text-align: center;
    padding: var(--spacing-2xl);
    color: var(--color-text-secondary);
}

.empty-state-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
    opacity: 0.5;
}

.empty-state-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--spacing-sm);
}

.empty-state-description {
    max-width: 400px;
    margin: 0 auto;
}

/* =====================================================
   Utilities
   ===================================================== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }

.hidden { display: none !important; }
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* =====================================================
   Animations
   ===================================================== */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate-fade-in {
    animation: fadeIn var(--transition-normal) ease-out;
}

.animate-slide-up {
    animation: slideUp var(--transition-normal) ease-out;
}

/* Staggered animation for grid items */
.gallery-grid .app-card {
    animation: slideUp var(--transition-normal) ease-out backwards;
}

.gallery-grid .app-card:nth-child(1) { animation-delay: 0ms; }
.gallery-grid .app-card:nth-child(2) { animation-delay: 50ms; }
.gallery-grid .app-card:nth-child(3) { animation-delay: 100ms; }
.gallery-grid .app-card:nth-child(4) { animation-delay: 150ms; }
.gallery-grid .app-card:nth-child(5) { animation-delay: 200ms; }
.gallery-grid .app-card:nth-child(6) { animation-delay: 250ms; }
.gallery-grid .app-card:nth-child(7) { animation-delay: 300ms; }
.gallery-grid .app-card:nth-child(8) { animation-delay: 350ms; }

/* =====================================================
   Responsive
   ===================================================== */
@media (max-width: 767px) {
    .gallery-grid {
        grid-template-columns: 1fr;
    }
    
    .app-detail-title {
        font-size: 1.5rem;
    }
    
    .challenge-day {
        font-size: 2rem;
    }
    
    .filter-section {
        flex-direction: column;
    }
    
    .search-box {
        min-width: 100%;
    }
}

@media (min-width: 768px) and (max-width: 1023px) {
    .gallery-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}