/* ============================================
   我的小栈 - Main Stylesheet
   ============================================ */

/* CSS Variables - Theme System */
:root {
    /* Colors - Light Theme */
    --color-bg: #ffffff;
    --color-bg-secondary: #f8f9fa;
    --color-bg-tertiary: #e9ecef;
    --color-text: #212529;
    --color-text-secondary: #6c757d;
    --color-text-muted: #adb5bd;
    --color-primary: #2563eb;
    --color-primary-hover: #1d4ed8;
    --color-accent: #8b5cf6;
    --color-border: #dee2e6;
    --color-shadow: rgba(0, 0, 0, 0.1);
    --color-card-bg: #ffffff;
    
    /* Typography */
    --font-serif: 'Noto Serif SC', serif;
    --font-sans: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'Fira Code', 'Consolas', monospace;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* Layout */
    --container-max: 1200px;
    --border-radius: 8px;
    --border-radius-lg: 12px;
    
    /* Transitions */
    --transition: all 0.3s ease;
}

/* Dark Theme */
[data-theme="dark"] {
    --color-bg: #1a1a1a;
    --color-bg-secondary: #2d2d2d;
    --color-bg-tertiary: #404040;
    --color-text: #e4e4e4;
    --color-text-secondary: #a0a0a0;
    --color-text-muted: #6c6c6c;
    --color-primary: #60a5fa;
    --color-primary-hover: #3b82f6;
    --color-accent: #a78bfa;
    --color-border: #404040;
    --color-shadow: rgba(0, 0, 0, 0.3);
    --color-card-bg: #2d2d2d;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    transition: var(--transition);
}

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

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

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

/* ============================================
   Navigation
   ============================================ */
.navbar {
    position: sticky;
    top: 0;
    z-index: 1000;
    background-color: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    backdrop-filter: blur(10px);
    background-color: rgba(var(--color-bg), 0.95);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md) var(--spacing-lg);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-family: var(--font-serif);
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text);
}

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

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

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
}

.nav-link {
    color: var(--color-text-secondary);
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-primary);
    background-color: var(--color-bg-secondary);
}

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

.theme-toggle,
.lang-toggle {
    background: none;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-sm) var(--spacing-md);
    cursor: pointer;
    font-size: 1rem;
    color: var(--color-text);
    transition: var(--transition);
}

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

.menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
}

.hamburger {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-text);
    position: relative;
    transition: var(--transition);
}

.hamburger::before,
.hamburger::after {
    content: '';
    position: absolute;
    width: 24px;
    height: 2px;
    background-color: var(--color-text);
    transition: var(--transition);
}

.hamburger::before {
    top: -8px;
}

.hamburger::after {
    bottom: -8px;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    position: relative;
    padding: var(--spacing-3xl) 0;
    background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-bg) 100%);
    overflow: hidden;
}

.hero-content {
    text-align: center;
    position: relative;
    z-index: 2;
}

.hero-title {
    font-family: var(--font-serif);
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xl);
}

.hero-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--border-radius);
    font-weight: 500;
    transition: var(--transition);
    border: 2px solid transparent;
}

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

.btn-primary:hover {
    background-color: var(--color-primary-hover);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--color-shadow);
}

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

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

.hero-decoration {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
}

.decoration-circle {
    position: absolute;
    border-radius: 50%;
    opacity: 0.1;
    animation: float 20s infinite ease-in-out;
}

.circle-1 {
    width: 300px;
    height: 300px;
    background: var(--color-primary);
    top: -100px;
    right: -100px;
    animation-delay: 0s;
}

.circle-2 {
    width: 200px;
    height: 200px;
    background: var(--color-accent);
    bottom: -50px;
    left: -50px;
    animation-delay: 5s;
}

.circle-3 {
    width: 150px;
    height: 150px;
    background: var(--color-primary);
    top: 50%;
    left: 50%;
    animation-delay: 10s;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0);
    }
    50% {
        transform: translate(30px, -30px);
    }
}

/* ============================================
   Featured Posts
   ============================================ */
.featured {
    padding: var(--spacing-3xl) 0;
}

.section-title {
    font-family: var(--font-serif);
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xl);
    text-align: center;
    color: var(--color-text);
}

.posts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.post-card {
    background-color: var(--color-card-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    transition: var(--transition);
    cursor: pointer;
}

.post-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px var(--color-shadow);
    border-color: var(--color-primary);
}

.post-category {
    display: inline-block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-primary);
    background-color: var(--color-bg-secondary);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing-md);
}

.post-title {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
    line-height: 1.3;
}

.post-excerpt {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.post-meta {
    display: flex;
    gap: var(--spacing-md);
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

/* ============================================
   Categories Section
   ============================================ */
.categories {
    padding: var(--spacing-3xl) 0;
    background-color: var(--color-bg-secondary);
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
}

.category-card {
    background-color: var(--color-card-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    transition: var(--transition);
}

.category-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px var(--color-shadow);
    border-color: var(--color-primary);
}

.category-icon {
    font-size: 3rem;
    display: block;
    margin-bottom: var(--spacing-md);
}

.category-name {
    font-family: var(--font-serif);
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.category-desc {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
}


/* ============================================
   Article Page
   ============================================ */
.article-header {
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
    text-align: center;
}

.article-header .article-category {
    display: inline-block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-primary);
    background-color: var(--color-bg-secondary);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing-lg);
}

.article-header .article-title {
    font-family: var(--font-serif);
    font-size: 2.25rem;
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

.article-header .article-meta {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    font-size: 0.9rem;
    color: var(--color-text-muted);
}

.article-content {
    max-width: 720px;
    margin: 0 auto;
    padding: var(--spacing-xl) 0 var(--spacing-3xl);
    font-size: 1.0625rem;
    line-height: 1.8;
    color: var(--color-text);
}

.article-content p {
    margin-bottom: var(--spacing-lg);
}

.article-content h2 {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    font-weight: 600;
    margin-top: var(--spacing-2xl);
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.article-content h3 {
    font-family: var(--font-serif);
    font-size: 1.25rem;
    font-weight: 600;
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.article-content ul,
.article-content ol {
    margin-bottom: var(--spacing-lg);
    padding-left: var(--spacing-xl);
}

.article-content li {
    margin-bottom: var(--spacing-sm);
}

.article-content blockquote {
    border-left: 3px solid var(--color-primary);
    padding-left: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
    color: var(--color-text-secondary);
    font-style: italic;
}

.article-content code {
    background-color: var(--color-bg-secondary);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.9em;
}

.article-content pre {
    background-color: var(--color-bg-secondary);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius);
    overflow-x: auto;
    margin-bottom: var(--spacing-lg);
}

.article-content pre code {
    background: none;
    padding: 0;
}

.article-back {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-xl);
}

.article-back:hover {
    color: var(--color-primary);
}

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

.footer-content {
    text-align: center;
}

.footer-brand {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    font-family: var(--font-serif);
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.footer-text {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
}

.footer-links {
    display: flex;
    gap: var(--spacing-lg);
    justify-content: center;
}

.footer-links a {
    color: var(--color-text-secondary);
    font-size: 0.875rem;
}

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

/* ICP Filing */
.footer-icp {
    margin-top: var(--spacing-sm);
    font-size: 0.8125rem;
}

.footer-icp a {
    color: var(--color-text-secondary);
}

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

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--color-bg);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px var(--color-shadow);
        padding: var(--spacing-xl) 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .menu-toggle {
        display: block;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .posts-grid {
        grid-template-columns: 1fr;
    }

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

@media (max-width: 480px) {
    .categories-grid {
        grid-template-columns: 1fr;
    }
}

/* ============================================
   Page Header (Sub-pages)
   ============================================ */
.page-header {
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
    background: linear-gradient(135deg, var(--color-bg-secondary) 0%, var(--color-bg) 100%);
    text-align: center;
}

.page-title {
    font-family: var(--font-serif);
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-md);
}

.page-icon {
    font-size: 2.5rem;
}

.page-subtitle {
    font-size: 1.125rem;
    color: var(--color-text-secondary);
}

.page-content {
    padding: var(--spacing-2xl) 0 var(--spacing-3xl);
    min-height: 50vh;
}

/* ============================================
   About Page
   ============================================ */
.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-section {
    margin-bottom: var(--spacing-2xl);
}

.about-section h2 {
    font-family: var(--font-serif);
    font-size: 1.75rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.about-section p {
    color: var(--color-text-secondary);
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
}

.about-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

.feature-item {
    text-align: center;
    padding: var(--spacing-lg);
    background-color: var(--color-bg-secondary);
    border-radius: var(--border-radius-lg);
    transition: var(--transition);
}

.feature-item:hover {
    transform: translateY(-4px);
    box-shadow: 0 4px 12px var(--color-shadow);
}

.feature-icon {
    font-size: 2rem;
    display: block;
    margin-bottom: var(--spacing-sm);
}

.feature-item h3 {
    font-family: var(--font-serif);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-xs);
}

.feature-item p {
    font-size: 0.875rem;
    margin-bottom: 0;
}

.contact-links {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.contact-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    background-color: var(--color-bg-secondary);
    border-radius: var(--border-radius);
    color: var(--color-text);
    transition: var(--transition);
}

.contact-link:hover {
    background-color: var(--color-primary);
    color: white;
    transform: translateY(-2px);
}

.post-tag {
    background-color: var(--color-bg-tertiary);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
}