/* ============================================
   TechFlow Blog — 全局变量与重置
   ============================================ */
:root {
    /* 暗色主题（默认） */
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --bg-hover: #30363d;
    --border-color: #30363d;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-tertiary: #6e7681;
    --accent: #58a6ff;
    --accent-hover: #79b8ff;
    --accent-dim: rgba(88, 166, 255, 0.15);
    --gradient-1: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-2: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.5);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
    --max-width: 860px;
    --nav-height: 64px;
}

[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f6f8fa;
    --bg-tertiary: #eaeef2;
    --bg-hover: #d8dde3;
    --border-color: #d0d7de;
    --text-primary: #1f2328;
    --text-secondary: #59636e;
    --text-tertiary: #818b98;
    --accent: #0969da;
    --accent-hover: #0550ae;
    --accent-dim: rgba(9, 105, 218, 0.1);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.12);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    transition: background 0.3s ease, color 0.3s ease;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

a {
    color: var(--accent);
    text-decoration: none;
    transition: color 0.2s ease;
}

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

/* ============================================
   导航栏
   ============================================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: background 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

.navbar.scrolled {
    box-shadow: var(--shadow-sm);
    background: var(--bg-secondary);
}

.nav-container {
    max-width: 1100px;
    height: 100%;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1.3rem;
    font-weight: 800;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

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

.logo-icon {
    font-size: 1.4rem;
    filter: drop-shadow(0 0 8px var(--accent));
}

.nav-links {
    display: flex;
    gap: 4px;
}

.nav-link {
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-size: 0.92rem;
    font-weight: 500;
    transition: all 0.2s ease;
}

.nav-link:hover {
    color: var(--text-primary);
    background: var(--bg-tertiary);
}

.nav-link.active {
    color: var(--accent);
    background: var(--accent-dim);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.nav-search {
    display: flex;
    align-items: center;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-secondary);
    transition: border-color 0.2s, box-shadow 0.2s;
}

.nav-search:focus-within {
    border-color: var(--accent);
    box-shadow: 0 0 0 2px var(--accent-dim);
}

.nav-search-icon {
    flex-shrink: 0;
    margin-left: 10px;
    color: var(--text-tertiary);
}

.nav-search input {
    width: 160px;
    padding: 8px 10px;
    border: none;
    background: transparent;
    color: var(--text-primary);
    font-size: 0.85rem;
    font-family: inherit;
    outline: none;
}

.nav-search input::placeholder {
    color: var(--text-tertiary);
}

/* 移动端隐藏 nav-search（菜单折叠时由汉堡菜单承载） */
@media (max-width: 768px) {
    .nav-search {
        display: none;
    }
}

.theme-toggle {
    width: 40px;
    height: 40px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--bg-secondary);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
}

.theme-toggle:hover {
    color: var(--text-primary);
    border-color: var(--accent);
    background: var(--bg-tertiary);
}

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

.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    width: 40px;
    height: 40px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--bg-secondary);
    cursor: pointer;
    align-items: center;
    justify-content: center;
}

.menu-toggle span {
    width: 18px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all 0.3s ease;
}

/* ============================================
   主内容区
   ============================================ */
.main-content {
    flex: 1;
    margin-top: var(--nav-height);
    padding: 0 24px;
}

/* ============================================
   首页 — Hero
   ============================================ */
.hero {
    max-width: 1100px;
    margin: 0 auto;
    padding: 80px 0 60px;
    text-align: center;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    border-radius: 100px;
    background: var(--accent-dim);
    border: 1px solid var(--accent);
    color: var(--accent);
    font-size: 0.82rem;
    font-weight: 600;
    margin-bottom: 24px;
}

.hero-badge .dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--accent);
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.3); }
}

.hero h1 {
    font-size: 3.2rem;
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -0.03em;
    margin-bottom: 20px;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.6;
}

/* 搜索框 */
.hero-search {
    display: flex;
    align-items: center;
    max-width: 480px;
    margin: 32px auto 0;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    overflow: hidden;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.hero-search:focus-within {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-dim);
}

.hero-search input {
    flex: 1;
    padding: 12px 20px;
    border: none;
    background: transparent;
    color: var(--text-primary);
    font-size: 0.92rem;
    font-family: inherit;
    outline: none;
}

.hero-search input::placeholder {
    color: var(--text-tertiary);
}

.hero-search button {
    padding: 10px 18px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    transition: color 0.2s;
}

.hero-search button:hover {
    color: var(--accent);
}

/* 独立搜索框（搜索结果页等） */
.search-inline {
    display: flex;
    align-items: center;
    gap: 10px;
}

.hero-stats {
    display: flex;
}

.hero-stat {
    text-align: center;
}

.hero-stat .num {
    font-size: 2rem;
    font-weight: 800;
    color: var(--accent);
}

.hero-stat .label {
    font-size: 0.85rem;
    color: var(--text-tertiary);
    margin-top: 4px;
}

/* ============================================
   文章列表
   ============================================ */
.section-header {
    max-width: 1100px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 32px;
}

.section-header h2 {
    font-size: 1.6rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.section-header .count {
    color: var(--text-tertiary);
    font-size: 0.9rem;
}

.article-grid {
    max-width: 1100px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 24px;
    padding-bottom: 80px;
}

.article-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
}

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

.card-cover {
    height: 160px;
    position: relative;
    overflow: hidden;
}

.card-cover::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 30% 50%, rgba(255,255,255,0.15), transparent 60%);
}

.card-body {
    padding: 24px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 12px;
}

.card-tag {
    padding: 3px 10px;
    border-radius: 100px;
    background: var(--accent-dim);
    color: var(--accent);
    font-size: 0.75rem;
    font-weight: 600;
}

.card-title {
    font-size: 1.15rem;
    font-weight: 700;
    line-height: 1.4;
    margin-bottom: 10px;
    color: var(--text-primary);
    letter-spacing: -0.01em;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.card-excerpt {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
    flex: 1;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    margin-bottom: 16px;
}

.card-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 0.82rem;
    color: var(--text-tertiary);
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.card-meta .meta-item {
    display: flex;
    align-items: center;
    gap: 5px;
}

/* ============================================
   文章详情
   ============================================ */
.article-detail {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 60px 0 100px;
}

.article-detail-header {
    margin-bottom: 40px;
}

.detail-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 20px;
}

.detail-tag {
    padding: 4px 14px;
    border-radius: 100px;
    background: var(--accent-dim);
    color: var(--accent);
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.detail-tag:hover {
    background: var(--accent);
    color: var(--bg-primary);
}

.detail-title {
    font-size: 2.4rem;
    font-weight: 800;
    line-height: 1.25;
    letter-spacing: -0.03em;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.detail-meta {
    display: flex;
    align-items: center;
    gap: 20px;
    color: var(--text-tertiary);
    font-size: 0.9rem;
}

.detail-meta .meta-item {
    display: flex;
    align-items: center;
    gap: 6px;
}

.detail-cover {
    height: 320px;
    border-radius: var(--radius-lg);
    margin-bottom: 48px;
    position: relative;
    overflow: hidden;
}

.detail-cover::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 40% 60%, rgba(255,255,255,0.2), transparent 60%);
}

/* Markdown 渲染样式 */
.markdown-body {
    font-size: 1.05rem;
    line-height: 1.85;
    color: var(--text-primary);
}

.markdown-body h2 {
    font-size: 1.6rem;
    font-weight: 700;
    margin: 48px 0 20px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--border-color);
    letter-spacing: -0.02em;
}

.markdown-body h3 {
    font-size: 1.3rem;
    font-weight: 700;
    margin: 36px 0 16px;
    letter-spacing: -0.01em;
}

.markdown-body h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin: 28px 0 12px;
}

.markdown-body p {
    margin-bottom: 20px;
}

.markdown-body a {
    color: var(--accent);
    text-decoration: underline;
    text-decoration-color: var(--accent-dim);
    text-underline-offset: 3px;
}

.markdown-body strong {
    font-weight: 700;
    color: var(--text-primary);
}

.markdown-body ul, .markdown-body ol {
    margin: 0 0 20px;
    padding-left: 28px;
}

.markdown-body li {
    margin-bottom: 8px;
}

.markdown-body blockquote {
    margin: 24px 0;
    padding: 16px 24px;
    border-left: 4px solid var(--accent);
    background: var(--bg-secondary);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    color: var(--text-secondary);
}

.markdown-body blockquote p {
    margin-bottom: 0;
}

.markdown-body code {
    font-family: var(--font-mono);
    font-size: 0.88em;
    padding: 2px 6px;
    border-radius: 4px;
    background: var(--bg-tertiary);
    color: var(--accent);
}

.markdown-body pre {
    margin: 24px 0;
    padding: 20px 24px;
    border-radius: var(--radius-md);
    background: #0d1117 !important;
    border: 1px solid var(--border-color);
    overflow-x: auto;
    position: relative;
}

.markdown-body pre code {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    padding: 0;
    background: none;
    color: #e6edf3;
    line-height: 1.6;
}

.markdown-body table {
    width: 100%;
    border-collapse: collapse;
    margin: 24px 0;
    font-size: 0.92rem;
    border-radius: var(--radius-sm);
    overflow: hidden;
    border: 1px solid var(--border-color);
}

.markdown-body th {
    background: var(--bg-tertiary);
    font-weight: 700;
    text-align: left;
    padding: 12px 16px;
    border-bottom: 2px solid var(--border-color);
}

.markdown-body td {
    padding: 10px 16px;
    border-bottom: 1px solid var(--border-color);
}

.markdown-body tr:last-child td {
    border-bottom: none;
}

.markdown-body tr:hover td {
    background: var(--bg-secondary);
}

.markdown-body img {
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
    display: block;
    margin: 20px auto;
}

.markdown-body hr {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 40px 0;
}

/* 文章底部 */
.article-footer {
    margin-top: 60px;
    padding-top: 32px;
    border-top: 1px solid var(--border-color);
}

.back-button {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: var(--radius-sm);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.back-button:hover {
    color: var(--accent);
    border-color: var(--accent);
}

/* ============================================
   标签页
   ============================================ */
.tags-page {
    max-width: 1100px;
    margin: 0 auto;
    padding: 60px 0 100px;
}

.page-title {
    font-size: 2.2rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    margin-bottom: 12px;
}

.page-subtitle {
    color: var(--text-secondary);
    font-size: 1.05rem;
    margin-bottom: 48px;
}

.tags-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 48px;
}

.tag-cloud-item {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: 100px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.tag-cloud-item:hover {
    border-color: var(--accent);
    color: var(--accent);
    transform: translateY(-2px);
}

.tag-cloud-item.active {
    background: var(--accent);
    color: var(--bg-primary);
    border-color: var(--accent);
}

.tag-cloud-item .tag-count {
    font-size: 0.8rem;
    opacity: 0.7;
    padding: 2px 8px;
    border-radius: 100px;
    background: var(--bg-tertiary);
}

.tag-cloud-item.active .tag-count {
    background: rgba(255,255,255,0.2);
}

/* ============================================
   栏目导航 (Pills)
   ============================================ */
.column-pill {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 20px;
    border-radius: 100px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.92rem;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.2s ease;
}

.column-pill:hover {
    border-color: var(--accent);
    color: var(--accent);
    transform: translateY(-1px);
}

.column-pill.active {
    background: var(--accent);
    color: var(--bg-primary);
    border-color: var(--accent);
}

/* 卡片上的栏目标识 */
.card-column-badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 3px 10px;
    border-radius: 4px;
    background: rgba(99, 102, 241, 0.12);
    color: var(--accent);
    font-size: 0.75rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

.card-column-badge:hover {
    background: rgba(99, 102, 241, 0.22);
}

/* 文章详情页栏目标识 */
.detail-column-badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 5px 14px;
    border-radius: 6px;
    background: rgba(99, 102, 241, 0.12);
    color: var(--accent);
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
    margin-right: 4px;
}

.detail-column-badge:hover {
    background: rgba(99, 102, 241, 0.22);
}

/* ============================================
   关于页面
   ============================================ */
.about-page {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 60px 0 100px;
}

.about-hero {
    text-align: center;
    margin-bottom: 60px;
}

.about-avatar {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: var(--gradient-1);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    margin: 0 auto 24px;
    box-shadow: var(--shadow-md);
}

.about-name {
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 8px;
}

.about-tagline {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.about-section {
    margin-bottom: 48px;
}

.about-section h2 {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
}

.about-section p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 16px;
}

.skill-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 16px;
}

.skill-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 18px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-weight: 500;
    transition: all 0.2s ease;
}

.skill-item:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
}

.skill-icon {
    font-size: 1.3rem;
}

.contact-links {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.contact-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    font-weight: 500;
    transition: all 0.2s ease;
}

.contact-link:hover {
    border-color: var(--accent);
    color: var(--accent);
    transform: translateY(-2px);
}

/* ============================================
   页脚
   ============================================ */
.footer {
    border-top: 1px solid var(--border-color);
    background: var(--bg-secondary);
    padding: 48px 24px;
    margin-top: auto;
}

.footer-container {
    max-width: 1100px;
    margin: 0 auto;
    text-align: center;
}

.footer-brand {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-size: 1.2rem;
    font-weight: 800;
    margin-bottom: 8px;
}

.footer-desc {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 20px;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-bottom: 24px;
}

.footer-links a {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

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

.footer-stats {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin-bottom: 24px;
    padding: 20px 0;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}

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

.footer-stat-num {
    display: block;
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--text-primary);
    font-variant-numeric: tabular-nums;
}

.footer-stat-label {
    display: block;
    font-size: 0.78rem;
    color: var(--text-tertiary);
    margin-top: 2px;
}

.footer-copy {
    color: var(--text-tertiary);
    font-size: 0.82rem;
}

/* ============================================
   返回顶部
   ============================================ */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--accent);
    color: var(--bg-primary);
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-md);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all 0.3s ease;
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

/* ============================================
   加载与动画
   ============================================ */
.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--bg-tertiary);
    border-top-color: var(--accent);
    border-radius: 50%;
    margin: 0 auto;
    animation: spin 0.8s linear infinite;
}

.load-sentinel {
    padding: 40px 0;
    text-align: center;
    min-height: 80px;
}

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

.fade-in {
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
}

.stagger > * {
    animation: fadeIn 0.5s ease backwards;
}

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

/* ============================================
   响应式
   ============================================ */
@media (max-width: 768px) {
    .nav-links {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        right: 0;
        flex-direction: column;
        background: var(--bg-secondary);
        border-bottom: 1px solid var(--border-color);
        padding: 16px;
        gap: 4px;
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: all 0.3s ease;
    }

    .nav-links.open {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
    }

    .nav-link {
        padding: 12px 16px;
    }

    .menu-toggle {
        display: flex;
    }

    .hero {
        padding: 48px 0 40px;
    }

    .hero h1 {
        font-size: 2.2rem;
    }

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

    .hero-stats {
        gap: 32px;
    }

    .hero-search {
        max-width: 100%;
        margin: 24px 16px 0;
    }

    .article-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .detail-title {
        font-size: 1.7rem;
    }

    .detail-cover {
        height: 200px;
    }

    .markdown-body {
        font-size: 1rem;
    }

    .markdown-body pre {
        font-size: 0.8rem;
        padding: 16px;
    }

    .page-title {
        font-size: 1.7rem;
    }

    .back-to-top {
        bottom: 20px;
        right: 20px;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 1.8rem;
    }

    .hero-stats {
        gap: 24px;
    }

    .hero-stat .num {
        font-size: 1.5rem;
    }

    .detail-title {
        font-size: 1.5rem;
    }

    .markdown-body h2 {
        font-size: 1.3rem;
    }

    .markdown-body table {
        font-size: 0.82rem;
    }
}

/* ============================================
   后台管理组件样式
   ============================================ */
.btn-sm {
    padding: 6px 12px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    background: var(--bg-tertiary);
    color: var(--text-primary);
    cursor: pointer;
    font-size: 0.82rem;
    transition: all 0.2s;
}
.btn-sm:hover {
    border-color: var(--accent);
    color: var(--accent);
}
.btn-sm.btn-danger {
    border-color: #ef4444;
    color: #ef4444;
    background: transparent;
}
.btn-sm.btn-danger:hover {
    background: #ef4444;
    color: #fff;
}

/* Markdown 编辑工具栏 */
.md-tool-btn {
    width: 32px;
    height: 32px;
    border-radius: 6px;
    border: 1px solid transparent;
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 0.82rem;
    transition: all 0.15s;
}
.md-tool-btn:hover {
    background: var(--bg-hover);
    border-color: var(--border-color);
    color: var(--text-primary);
}

/* 封面切换 tab */
.cover-type-btn.active {
    border-color: var(--accent) !important;
    background: rgba(99,102,241,0.1) !important;
    color: var(--accent) !important;
}

/* 上传区域 hover 效果 */
.upload-zone {
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    padding: 24px;
    text-align: center;
    background: var(--bg-tertiary);
    cursor: pointer;
    transition: border-color 0.2s;
}
.upload-zone:hover {
    border-color: var(--accent);
}

/* 管理员统计卡片 */
.admin-stat-card {
    transition: transform 0.2s, box-shadow 0.2s;
}
.admin-stat-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(0,0,0,0.2);
}