/* GitHub-Style Octocat Adventures CSS */
/* Based on GitHub's official design system */

/* CSS Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* CSS Custom Properties - GitHub Dark Theme */
:root {
    /* GitHub Official Colors */
    --color-canvas-default: #0d1117;
    --color-canvas-overlay: #161b22;
    --color-canvas-inset: #010409;
    --color-canvas-subtle: #21262d;
    
    --color-fg-default: #c9d1d9;
    --color-fg-muted: #8b949e;
    --color-fg-subtle: #6e7681;
    --color-fg-on-emphasis: #ffffff;
    
    --color-accent-fg: #58a6ff;
    --color-accent-emphasis: #1f6feb;
    --color-accent-muted: rgba(88, 166, 255, 0.4);
    --color-accent-subtle: rgba(88, 166, 255, 0.1);
    
    --color-success-fg: #3fb950;
    --color-danger-fg: #f85149;
    --color-warning-fg: #d29922;
    
    --color-border-default: #30363d;
    --color-border-muted: #21262d;
    --color-border-subtle: rgba(240, 246, 252, 0.1);
    
    /* Shadows */
    --color-shadow-small: 0 1px 0 rgba(1, 4, 9, 0.04);
    --color-shadow-medium: 0 3px 6px rgba(1, 4, 9, 0.12);
    --color-shadow-large: 0 8px 24px rgba(1, 4, 9, 0.12);
    --color-shadow-extra-large: 0 12px 28px rgba(1, 4, 9, 0.15);
    
    /* GitHub Typography */
    --fontStack-system: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
    --fontStack-monospace: ui-monospace, SFMono-Regular, "SF Mono", Consolas, "Liberation Mono", Menlo, monospace;
    
    /* Font Sizes */
    --text-body-size-small: 12px;
    --text-body-size-medium: 14px;
    --text-body-size-large: 16px;
    --text-title-size-small: 16px;
    --text-title-size-medium: 20px;
    --text-title-size-large: 24px;
    --text-display-size-small: 28px;
    --text-display-size-medium: 32px;
    --text-display-size-large: 40px;
    
    /* Spacing Scale */
    --base-size-4: 4px;
    --base-size-8: 8px;
    --base-size-12: 12px;
    --base-size-16: 16px;
    --base-size-20: 20px;
    --base-size-24: 24px;
    --base-size-32: 32px;
    --base-size-40: 40px;
    --base-size-48: 48px;
    --base-size-64: 64px;
    --base-size-80: 80px;
    --base-size-96: 96px;
    
    /* Border Radius */
    --borderRadius-small: 3px;
    --borderRadius-medium: 6px;
    --borderRadius-large: 8px;
    --borderRadius-full: 50%;
    
    /* Transitions */
    --animation-duration: 0.2s;
    --animation-easing: cubic-bezier(0.2, 0, 0.13, 1.5);
}

/* Base Styles */
html {
    font-size: 14px;
    line-height: 1.5;
    color: var(--color-fg-default);
    background-color: var(--color-canvas-default);
    scroll-behavior: smooth;
}

body {
    font-family: var(--fontStack-system);
    font-size: var(--text-body-size-medium);
    line-height: 1.5;
    color: var(--color-fg-default);
    background-color: var(--color-canvas-default);
    -webkit-text-size-adjust: 100%;
    -webkit-font-feature-settings: "kern" 1;
    -moz-font-feature-settings: "kern" 1;
    -o-font-feature-settings: "kern" 1;
    font-feature-settings: "kern" 1;
    font-kerning: normal;
}

/* Header Styles */
.header {
    position: sticky;
    top: 0;
    z-index: 32;
    background-color: var(--color-canvas-overlay);
    border-bottom: 1px solid var(--color-border-default);
    transition: box-shadow var(--animation-duration) ease;
}

.header.scrolled {
    box-shadow: var(--color-shadow-large);
}

.nav {
    padding: var(--base-size-16) 0;
}

.nav-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--base-size-24);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--base-size-12);
    text-decoration: none;
}

.nav-logo {
    width: 32px;
    height: 32px;
    border-radius: var(--borderRadius-medium);
}

.nav-title {
    font-size: var(--text-title-size-small);
    font-weight: 600;
    color: var(--color-fg-default);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--base-size-24);
}

.nav-link {
    color: var(--color-fg-default);
    text-decoration: none;
    font-weight: 500;
    padding: var(--base-size-8) var(--base-size-12);
    border-radius: var(--borderRadius-medium);
    transition: all var(--animation-duration) ease;
    position: relative;
}

.nav-link:hover {
    color: var(--color-accent-fg);
    background-color: var(--color-accent-subtle);
}

.nav-link-external::after {
    content: "↗";
    margin-left: var(--base-size-4);
    font-size: 12px;
    opacity: 0.7;
}

/* Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--base-size-8) var(--base-size-16);
    font-size: var(--text-body-size-medium);
    font-weight: 500;
    line-height: 1.5;
    white-space: nowrap;
    vertical-align: middle;
    cursor: pointer;
    user-select: none;
    border: 1px solid;
    border-radius: var(--borderRadius-medium);
    text-decoration: none;
    transition: all var(--animation-duration) ease;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    color: var(--color-fg-on-emphasis);
    background-color: var(--color-accent-emphasis);
    border-color: var(--color-accent-emphasis);
    box-shadow: var(--color-shadow-small), inset 0 1px 0 rgba(255, 255, 255, 0.25);
}

.btn-primary:hover {
    background-color: #1f6feb;
    border-color: #1f6feb;
    box-shadow: var(--color-shadow-medium), inset 0 1px 0 rgba(255, 255, 255, 0.25);
    transform: translateY(-1px);
}

.btn-primary::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.6s;
}

.btn-primary:hover::before {
    left: 100%;
}

.btn-secondary {
    color: var(--color-fg-default);
    background-color: transparent;
    border-color: var(--color-border-default);
    box-shadow: var(--color-shadow-small);
}

.btn-secondary:hover {
    background-color: var(--color-canvas-subtle);
    border-color: var(--color-accent-muted);
    box-shadow: var(--color-shadow-medium);
    transform: translateY(-1px);
}

.hero-actions {
    display: flex;
    gap: var(--base-size-16);
    justify-content: center;
    flex-wrap: wrap;
}

/* Hero Section */
.hero {
    padding: var(--base-size-96) 0 var(--base-size-80);
    background: linear-gradient(135deg, var(--color-canvas-default) 0%, var(--color-canvas-overlay) 50%, var(--color-canvas-default) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(ellipse at center, rgba(88, 166, 255, 0.1) 0%, transparent 70%);
    pointer-events: none;
}

.hero-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--base-size-24);
    text-align: center;
    position: relative;
    z-index: 1;
}

.hero-content {
    max-width: 768px;
    margin: 0 auto;
}

.hero-logo {
    margin-bottom: var(--base-size-48);
    display: inline-block;
}

.hero-image {
    width: 200px;
    height: 200px;
    border-radius: var(--borderRadius-large);
    box-shadow: var(--color-shadow-extra-large);
    animation: bounce 2s ease-in-out infinite;
    transition: transform var(--animation-duration) ease;
}

.hero-image:hover {
    transform: scale(1.05);
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-10px);
    }
    60% {
        transform: translateY(-5px);
    }
}

.hero-title {
    font-size: var(--text-display-size-large);
    font-weight: 600;
    line-height: 1.25;
    color: var(--color-fg-default);
    margin-bottom: var(--base-size-24);
}

.hero-description {
    font-size: var(--text-body-size-large);
    color: var(--color-fg-muted);
    margin-bottom: var(--base-size-40);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* Section Styles */
.gallery {
    padding: var(--base-size-80) 0;
    background-color: var(--color-canvas-default);
}

.facts {
    padding: var(--base-size-80) 0;
    background-color: var(--color-canvas-overlay);
}

.community {
    padding: var(--base-size-80) 0;
    background-color: var(--color-canvas-default);
}

.gallery-container,
.facts-container,
.community-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--base-size-24);
}

.section-title {
    font-size: var(--text-display-size-medium);
    font-weight: 600;
    text-align: center;
    color: var(--color-fg-default);
    margin-bottom: var(--base-size-16);
}

.section-subtitle {
    font-size: var(--text-body-size-large);
    color: var(--color-fg-muted);
    text-align: center;
    margin-bottom: var(--base-size-64);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* Gallery Styles */
.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--base-size-24);
}

.gallery-card {
    background-color: var(--color-canvas-overlay);
    border: 1px solid var(--color-border-default);
    border-radius: var(--borderRadius-large);
    overflow: hidden;
    transition: all var(--animation-duration) ease;
    position: relative;
}

.gallery-card:hover {
    border-color: var(--color-accent-muted);
    box-shadow: var(--color-shadow-large);
    transform: translateY(-4px);
}

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

.gallery-link {
    display: block;
    text-decoration: none;
    color: inherit;
}

.gallery-image-container {
    position: relative;
    overflow: hidden;
    background-color: var(--color-canvas-subtle);
}

.gallery-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    transition: transform var(--animation-duration) ease;
}

.gallery-content {
    padding: var(--base-size-20);
}

.gallery-title {
    font-size: var(--text-title-size-medium);
    font-weight: 600;
    color: var(--color-fg-default);
    margin-bottom: var(--base-size-8);
}

.gallery-caption {
    font-size: var(--text-body-size-medium);
    color: var(--color-fg-muted);
    font-style: italic;
}

/* Facts Section */
.facts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--base-size-24);
}

.fact-card {
    background-color: var(--color-canvas-default);
    border: 1px solid var(--color-border-default);
    border-radius: var(--borderRadius-large);
    padding: var(--base-size-24);
    transition: all var(--animation-duration) ease;
    position: relative;
}

.fact-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-accent-emphasis), var(--color-success-fg));
    border-radius: var(--borderRadius-large) var(--borderRadius-large) 0 0;
    transform: scaleX(0);
    transition: transform var(--animation-duration) ease;
}

.fact-card:hover::before {
    transform: scaleX(1);
}

.fact-card:hover {
    border-color: var(--color-accent-muted);
    box-shadow: var(--color-shadow-medium);
    transform: translateY(-2px);
}

.fact-icon {
    margin-bottom: var(--base-size-16);
    display: flex;
    align-items: center;
    justify-content: center;
}

.fact-octocat {
    width: 32px;
    height: 32px;
    opacity: 0.8;
    transition: all var(--animation-duration) ease;
}

.fact-card:hover .fact-octocat {
    opacity: 1;
    transform: scale(1.1);
}

.fact-title {
    font-size: var(--text-title-size-small);
    font-weight: 600;
    color: var(--color-fg-default);
    margin-bottom: var(--base-size-12);
}

.fact-description {
    color: var(--color-fg-muted);
    line-height: 1.6;
}

/* Community Section */
.community-card {
    max-width: 600px;
    margin: 0 auto;
    background-color: var(--color-canvas-overlay);
    border: 1px solid var(--color-border-default);
    border-radius: var(--borderRadius-large);
    padding: var(--base-size-40);
    text-align: center;
    transition: all var(--animation-duration) ease;
    position: relative;
    overflow: hidden;
}

.community-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--color-accent-emphasis), #1d9bf0);
    border-radius: var(--borderRadius-large) var(--borderRadius-large) 0 0;
    transform: scaleX(0);
    transition: transform var(--animation-duration) ease;
}

.community-card:hover::before {
    transform: scaleX(1);
}

.community-card:hover {
    border-color: var(--color-accent-muted);
    box-shadow: var(--color-shadow-large);
    transform: translateY(-4px);
}

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

.community-icon {
    margin-bottom: var(--base-size-24);
    display: flex;
    align-items: center;
    justify-content: center;
}

.community-octocat {
    width: 64px;
    height: 64px;
    transition: all var(--animation-duration) ease;
    filter: drop-shadow(var(--color-shadow-medium));
}

.community-card:hover .community-octocat {
    transform: scale(1.1) rotate(5deg);
}

.community-title {
    font-size: var(--text-title-size-large);
    font-weight: 600;
    color: var(--color-fg-default);
    margin-bottom: var(--base-size-16);
}

.community-description {
    color: var(--color-fg-muted);
    line-height: 1.6;
    margin-bottom: var(--base-size-32);
    font-size: var(--text-body-size-large);
}

.community-btn {
    font-size: var(--text-body-size-large);
    padding: var(--base-size-12) var(--base-size-24);
    position: relative;
    overflow: hidden;
}

.community-btn::after {
    content: '';
    position: absolute;
    top: 50%;
    right: 16px;
    transform: translateY(-50%);
    width: 0;
    height: 0;
    border-left: 6px solid currentColor;
    border-top: 4px solid transparent;
    border-bottom: 4px solid transparent;
    opacity: 0.7;
    transition: all var(--animation-duration) ease;
}

.community-btn:hover::after {
    right: 12px;
    opacity: 1;
}

/* Footer */
.footer {
    background-color: var(--color-canvas-inset);
    border-top: 1px solid var(--color-border-default);
    padding: var(--base-size-48) 0 var(--base-size-24);
}

.footer-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--base-size-24);
}

.footer-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--base-size-32);
}

.footer-watermark {
    opacity: 0.6;
}

.footer-octocat {
    width: 32px;
    height: 32px;
    transition: all var(--animation-duration) ease;
}

.footer-octocat:hover {
    opacity: 1;
    transform: rotate(360deg);
}

.footer-links {
    display: flex;
    gap: var(--base-size-24);
}

.footer-link {
    color: var(--color-fg-muted);
    text-decoration: none;
    font-size: var(--text-body-size-medium);
    transition: color var(--animation-duration) ease;
}

.footer-link:hover {
    color: var(--color-accent-fg);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--base-size-24);
    border-top: 1px solid var(--color-border-default);
}

.footer-credit {
    color: var(--color-fg-subtle);
    font-size: var(--text-body-size-small);
}

/* Responsive Design */
@media (max-width: 1012px) {
    .nav-container {
        padding: 0 var(--base-size-16);
    }
    
    .hero-container,
    .gallery-container,
    .facts-container,
    .footer-container {
        padding: 0 var(--base-size-16);
    }
    
    .nav-links {
        gap: var(--base-size-16);
    }
    
    .gallery-grid {
        grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
        gap: var(--base-size-20);
    }
    
    .facts-grid {
        grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
        gap: var(--base-size-20);
    }
}

@media (max-width: 768px) {
    .hero {
        padding: var(--base-size-64) 0 var(--base-size-48);
    }
    
    .hero-title {
        font-size: var(--text-display-size-medium);
    }
    
    .hero-image {
        width: 150px;
        height: 150px;
    }
    
    .gallery,
    .facts,
    .community {
        padding: var(--base-size-64) 0;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: center;
        gap: var(--base-size-12);
    }
    
    .community-card {
        padding: var(--base-size-24);
    }
    
    .community-octocat {
        width: 48px;
        height: 48px;
    }
    
    .gallery-grid,
    .facts-grid {
        grid-template-columns: 1fr;
        gap: var(--base-size-16);
    }
    
    .footer-content {
        flex-direction: column;
        gap: var(--base-size-20);
        text-align: center;
    }
    
    .footer-links {
        justify-content: center;
        flex-wrap: wrap;
        gap: var(--base-size-16);
    }
}

@media (max-width: 544px) {
    .nav-container {
        padding: 0 var(--base-size-12);
    }
    
    .hero-container,
    .gallery-container,
    .facts-container,
    .community-container,
    .footer-container {
        padding: 0 var(--base-size-12);
    }
    
    .nav-links {
        gap: var(--base-size-12);
    }
    
    .nav-link {
        padding: var(--base-size-4) var(--base-size-8);
        font-size: var(--text-body-size-small);
    }
    
    .hero-title {
        font-size: var(--text-display-size-small);
    }
    
    .section-title {
        font-size: var(--text-title-size-large);
    }
    
    .fact-card {
        padding: var(--base-size-16);
    }
}

/* Focus Styles for Accessibility */
.nav-link:focus,
.btn:focus,
.gallery-link:focus,
.footer-link:focus {
    outline: 2px solid var(--color-accent-fg);
    outline-offset: 2px;
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
    
    .hero-image {
        animation: none;
    }
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
    :root {
        --color-border-default: #ffffff;
        --color-fg-muted: #ffffff;
        --color-accent-fg: #79c0ff;
    }
}

/* Print Styles */
@media print {
    .header,
    .footer {
        display: none;
    }
    
    .hero {
        padding-top: 0;
    }
    
    body {
        color: #000;
        background: #fff;
    }
}