@import url('https://fonts.googleapis.com/css2?family=Kalam:wght@400;700&family=Patrick+Hand&display=swap');

/* ===== CSS 变量 ===== */
:root {
  --mint: #5cc6b0;
  --sand: #d4c4a8;
  --dark: #172623;
  --mint-light: #a8e4d8;
  --mint-dim: #3a9e8a;
  --sand-dark: #b8a88a;
  --sand-light: #ede5d6;
  --dark-mid: #243c38;
  --dark-light: #2e4e49;
  --white: #faf9f6;
  --text: #1a2e2a;
  --text-muted: #5a7a74;
  --glass-bg: rgba(212, 196, 168, 0.18);
  --glass-border: rgba(92, 198, 176, 0.25);
  --grain-opacity: 0.04;
  --nav-width: 260px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --radius-xl: 32px;
  --shadow-soft: 0 4px 24px rgba(23, 38, 35, 0.12);
  --shadow-card: 0 2px 16px rgba(23, 38, 35, 0.08);
  --transition: 0.3s ease-out;
  --font-hand: 'Kalam', 'Patrick Hand', cursive;
  --font-body: 'Patrick Hand', -apple-system, 'Helvetica Neue', sans-serif;
}

/* ===== 重置 ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 17px; scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  background-color: var(--dark);
  color: var(--sand);
  line-height: 1.65;
  min-height: 100vh;
  overflow-x: hidden;
}

/* ===== 纹理叠加 ===== */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='300' height='300'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.75' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='300' height='300' filter='url(%23noise)' opacity='0.04'/%3E%3C/svg%3E");
  opacity: var(--grain-opacity);
}

/* ===== 布局骨架 ===== */
.site-wrapper {
  display: flex;
  min-height: 100vh;
  position: relative;
  z-index: 1;
}

/* ===== 侧边导航 ===== */
.side-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--nav-width);
  height: 100vh;
  background: var(--dark-mid);
  border-right: 1px solid var(--glass-border);
  display: flex;
  flex-direction: column;
  padding: 0;
  z-index: 100;
  overflow-y: auto;
  overflow-x: hidden;
}

.side-nav::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--mint), var(--sand));
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 28px 20px 12px;
  text-decoration: none;
}

.nav-logo {
  width: 36px;
  height: 36px;
  object-fit: contain;
  border-radius: var(--radius-sm);
}

.nav-brand-name {
  font-family: var(--font-hand);
  font-weight: 700;
  font-size: 1rem;
  color: var(--mint);
  line-height: 1.3;
  word-break: break-all;
}

.nav-tagline {
  font-size: 0.72rem;
  color: var(--text-muted);
  padding: 0 20px 18px;
  border-bottom: 1px solid rgba(92,198,176,0.12);
  line-height: 1.4;
}

.side-nav ol {
  list-style: none;
  padding: 12px 0;
  flex: 1;
}

.side-nav ol li {
  margin: 2px 0;
}

.side-nav ol li a {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 12px 20px;
  color: var(--sand);
  text-decoration: none;
  font-size: 0.88rem;
  line-height: 1.4;
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  margin-right: 12px;
  transition: background var(--transition), color var(--transition);
  min-height: 44px;
}

.side-nav ol li a:hover,
.side-nav ol li a.active {
  background: rgba(92, 198, 176, 0.15);
  color: var(--mint);
}

.nav-num {
  font-family: var(--font-hand);
  font-size: 0.72rem;
  color: var(--mint-dim);
  min-width: 22px;
  padding-top: 1px;
  letter-spacing: 0.03em;
}

.nav-label {
  flex: 1;
}

/* ===== 页面主体 ===== */
.page-body {
  margin-left: var(--nav-width);
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.page-body main {
  flex: 1;
}

/* ===== 公共组件 ===== */
.eyebrow {
  display: inline-block;
  font-size: 0.72rem;
  font-family: var(--font-hand);
  letter-spacing: 0.08em;
  color: var(--mint);
  text-transform: uppercase;
  margin-bottom: 6px;
}

.glass-card {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: var(--shadow-card);
}

.btn-primary {
  display: inline-block;
  padding: 13px 28px;
  background: var(--mint);
  color: var(--dark);
  text-decoration: none;
  font-family: var(--font-hand);
  font-weight: 700;
  font-size: 1rem;
  border-radius: var(--radius-xl);
  transition: transform var(--transition), background var(--transition);
  min-height: 44px;
  line-height: 1.2;
}

.btn-primary:hover {
  background: var(--mint-dim);
  transform: translateY(-2px);
}

.content-body {
  font-size: 1rem;
  line-height: 1.75;
  color: var(--sand);
  max-width: 720px;
}

.content-body h2 {
  font-family: var(--font-hand);
  font-size: 1.4rem;
  color: var(--mint);
  margin: 2rem 0 0.8rem;
  font-weight: 700;
}

.content-body h3 {
  font-family: var(--font-hand);
  font-size: 1.15rem;
  color: var(--sand);
  margin: 1.5rem 0 0.6rem;
}

.content-body p {
  margin-bottom: 1rem;
}

.content-body a {
  color: var(--mint);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.content-body ul, .content-body ol {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}

.content-body li {
  margin-bottom: 0.4rem;
}

.content-body time {
  color: var(--text-muted);
  font-size: 0.88rem;
}

/* ===== 页脚 ===== */
footer {
  background: var(--dark);
  border-top: 1px solid var(--glass-border);
  padding: 40px 48px 28px;
  margin-top: auto;
}

.footer-brand {
  font-family: var(--font-hand);
  font-size: 2.8rem;
  font-weight: 700;
  color: rgba(92, 198, 176, 0.15);
  line-height: 1;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
  word-break: break-all;
}

footer small {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.6;
}

footer small a {
  color: var(--sand);
  text-decoration: none;
  margin: 0 4px;
}

footer small a:hover {
  color: var(--mint);
}

/* ===== 首页 Hero ===== */
.hero-section {
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-height: 70vh;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding: 60px 48px 60px 40px;
  gap: 40px;
  background: linear-gradient(135deg, var(--dark) 0%, var(--dark-mid) 100%);
}

.hero-aside {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-bg-text {
  position: absolute;
  font-family: var(--font-hand);
  font-size: 8rem;
  font-weight: 700;
  color: rgba(92, 198, 176, 0.06);
  letter-spacing: 0.1em;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  white-space: nowrap;
  pointer-events: none;
  user-select: none;
  z-index: 0;
}

.hero-imgs {
  position: relative;
  width: 340px;
  height: 380px;
}

.hero-img-wrap {
  position: absolute;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-soft);
}

.hero-img-wrap-a {
  width: 220px;
  height: 280px;
  top: 0;
  left: 0;
  z-index: 2;
  border: 3px solid var(--mint);
}

.hero-img-wrap-b {
  width: 200px;
  height: 240px;
  bottom: 0;
  right: 0;
  z-index: 1;
  border: 3px solid var(--sand);
}

.hero-placeholder-a {
  background: linear-gradient(135deg, var(--dark-light), var(--dark-mid));
  width: 220px;
  height: 280px;
  top: 0;
  left: 0;
  z-index: 2;
  border: 3px solid var(--mint);
}

.hero-placeholder-b {
  background: linear-gradient(135deg, var(--dark-mid), var(--dark-light));
  width: 200px;
  height: 240px;
  bottom: 0;
  right: 0;
  z-index: 1;
  border: 3px solid var(--sand);
}

.hero-img-wrap img,
.hero-img-wrap-a img,
.hero-img-wrap-b img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.hero-content {
  text-align: right;
  z-index: 2;
}

.hero-h1 {
  font-family: var(--font-hand);
  font-size: 2.4rem;
  font-weight: 700;
  color: var(--mint);
  line-height: 1.25;
  margin-bottom: 16px;
  word-break: break-all;
}

.hero-desc {
  font-size: 1rem;
  color: var(--sand);
  line-height: 1.7;
  margin-bottom: 28px;
  max-width: 380px;
  margin-left: auto;
}

/* ===== 首页 Topic 区块 ===== */
.topics-section {
  padding: 60px 48px 40px;
  background: var(--dark-mid);
}

.topics-section h2 {
  font-family: var(--font-hand);
  font-size: 1.6rem;
  color: var(--sand);
  margin-bottom: 28px;
}

.topics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
}

.topic-block {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 24px 20px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  text-decoration: none;
  backdrop-filter: blur(10px);
  transition: transform var(--transition), border-color var(--transition);
  min-height: 44px;
}

.topic-block:hover {
  transform: translateY(-3px);
  border-color: var(--mint);
}

.topic-block strong {
  font-family: var(--font-hand);
  font-size: 1rem;
  font-weight: 700;
  color: var(--mint);
  display: block;
}

.topic-block span {
  font-size: 0.85rem;
  color: var(--sand);
  line-height: 1.5;
}

/* ===== 首页文章列表 ===== */
.articles-section {
  padding: 60px 48px;
  background: var(--dark);
}

.articles-section h2 {
  font-family: var(--font-hand);
  font-size: 1.6rem;
  color: var(--sand);
  margin-bottom: 28px;
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
  margin-bottom: 40px;
}

.card {
  padding: 24px;
  transition: transform var(--transition);
}

.card:hover {
  transform: translateY(-4px);
}

.card-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 10px;
  flex-wrap: wrap;
}

.card-cat {
  font-size: 0.75rem;
  background: rgba(92, 198, 176, 0.15);
  color: var(--mint);
  padding: 2px 10px;
  border-radius: 20px;
  border: 1px solid rgba(92, 198, 176, 0.25);
}

.card-meta time {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.card h3 {
  font-family: var(--font-hand);
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 8px;
  line-height: 1.4;
}

.card h3 a {
  color: var(--sand);
  text-decoration: none;
  transition: color var(--transition);
}

.card h3 a:hover {
  color: var(--mint);
}

.card p {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.55;
}

/* ===== 面包屑 ===== */
.article-breadcrumb,
.tag-breadcrumb,
.breadcrumb-aside {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.article-breadcrumb a,
.tag-breadcrumb a,
.breadcrumb-aside a {
  color: var(--mint);
  text-decoration: none;
}

.article-breadcrumb a:hover,
.tag-breadcrumb a:hover,
.breadcrumb-aside a:hover {
  text-decoration: underline;
}

/* ===== 专题页 ===== */
.topic-hero {
  padding: 52px 48px 40px;
  background: linear-gradient(135deg, var(--dark) 0%, var(--dark-mid) 100%);
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.topic-hero-fig {
  max-width: 680px;
}

.topic-hero-fig h1 {
  font-family: var(--font-hand);
  font-size: 2rem;
  font-weight: 700;
  color: var(--mint);
  margin: 8px 0 12px;
  line-height: 1.3;
}

.topic-desc {
  font-size: 1rem;
  color: var(--sand);
  line-height: 1.7;
}

.topic-content-section {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 40px;
  padding: 48px 48px 60px;
  align-items: start;
}

.topic-aside,
.article-aside,
.tag-aside,
.about-aside,
.privacy-aside,
.default-aside {
  position: sticky;
  top: 24px;
}

.topic-aside h3,
.article-aside h3,
.tag-aside h3,
.about-aside h3,
.privacy-aside h3,
.default-aside h3 {
  font-family: var(--font-hand);
  font-size: 1rem;
  color: var(--sand);
  margin-bottom: 12px;
}

.aside-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin-bottom: 24px;
}

.aside-links li a {
  display: block;
  padding: 9px 12px;
  font-size: 0.88rem;
  color: var(--sand);
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: background var(--transition), color var(--transition);
  min-height: 40px;
  line-height: 1.4;
  display: flex;
  align-items: center;
}

.aside-links li a:hover {
  background: rgba(92, 198, 176, 0.1);
  color: var(--mint);
}

/* ===== 子页列表 ===== */
.children-section {
  margin-top: 40px;
}

.children-section h2 {
  font-family: var(--font-hand);
  font-size: 1.4rem;
  color: var(--sand);
  margin-bottom: 20px;
}

.children-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
}

.child-block {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 20px 18px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  text-decoration: none;
  backdrop-filter: blur(8px);
  transition: transform var(--transition), border-color var(--transition);
}

.child-block:hover {
  transform: translateY(-3px);
  border-color: var(--mint);
}

.child-block strong {
  font-family: var(--font-hand);
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--mint);
  display: block;
  line-height: 1.4;
}

.child-block .child-desc {
  font-size: 0.83rem;
  color: var(--sand);
  line-height: 1.5;
}

.child-block time {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 4px;
}

/* ===== 文章页 ===== */
.article-header-section {
  padding: 40px 48px 36px;
  background: linear-gradient(160deg, var(--dark) 0%, var(--dark-mid) 100%);
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.article-header-fig {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  align-items: center;
  max-width: 900px;
}

.article-hero-img {
  width: 100%;
  height: 260px;
  object-fit: cover;
  border-radius: var(--radius-md);
  display: block;
}

.article-header-text h1 {
  font-family: var(--font-hand);
  font-size: 1.9rem;
  font-weight: 700;
  color: var(--mint);
  line-height: 1.3;
  margin: 8px 0 14px;
}

.article-meta {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.article-meta time {
  color: var(--text-muted);
}

.article-body-section {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 40px;
  padding: 48px 48px 60px;
  align-items: start;
}

.aside-related {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 20px;
}

.related-link {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px;
  background: rgba(92, 198, 176, 0.06);
  border: 1px solid rgba(92, 198, 176, 0.12);
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: border-color var(--transition), background var(--transition);
}

.related-link:hover {
  border-color: var(--mint);
  background: rgba(92, 198, 176, 0.12);
}

.related-link strong {
  font-size: 0.85rem;
  color: var(--mint);
  font-weight: 600;
  line-height: 1.4;
}

.related-link span {
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.aside-tags {
  margin-top: 20px;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 8px;
}

.tag-chip {
  display: inline-block;
  padding: 5px 14px;
  background: rgba(92, 198, 176, 0.1);
  border: 1px solid rgba(92, 198, 176, 0.2);
  border-radius: 20px;
  font-size: 0.82rem;
  color: var(--mint);
  text-decoration: none;
  transition: background var(--transition);
  min-height: 40px;
  line-height: 28px;
}

.tag-chip:hover {
  background: rgba(92, 198, 176, 0.2);
}

.article-content {
  max-width: 720px;
}

.article-footer-nav {
  display: flex;
  gap: 14px;
  margin-top: 40px;
  flex-wrap: wrap;
}

.back-link {
  display: inline-block;
  padding: 10px 20px;
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  font-size: 0.88rem;
  color: var(--sand);
  text-decoration: none;
  min-height: 44px;
  line-height: 22px;
  transition: border-color var(--transition), color var(--transition);
}

.back-link:hover {
  border-color: var(--mint);
  color: var(--mint);
}

/* ===== 标签页 ===== */
.tag-header-section {
  padding: 48px 48px 36px;
  background: linear-gradient(135deg, var(--dark), var(--dark-mid));
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.tag-header-fig h1 {
  font-family: var(--font-hand);
  font-size: 2rem;
  font-weight: 700;
  color: var(--mint);
  margin: 8px 0 12px;
}

.tag-header-fig p {
  color: var(--sand);
  line-height: 1.7;
  max-width: 560px;
}

.tag-content-section {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 40px;
  padding: 48px 48px 60px;
  align-items: start;
}

.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

.tag-nav-chip {
  display: inline-block;
  padding: 8px 16px;
  background: rgba(92, 198, 176, 0.08);
  border: 1px solid rgba(92, 198, 176, 0.18);
  border-radius: 20px;
  font-size: 0.85rem;
  color: var(--sand);
  text-decoration: none;
  transition: background var(--transition), color var(--transition);
  min-height: 40px;
  line-height: 22px;
}

.tag-nav-chip:hover,
.tag-nav-chip.active {
  background: rgba(92, 198, 176, 0.2);
  color: var(--mint);
  border-color: var(--mint);
}

.tag-articles {
  margin-top: 40px;
}

.tag-articles h2 {
  font-family: var(--font-hand);
  font-size: 1.4rem;
  color: var(--sand);
  margin-bottom: 20px;
}

/* ===== 关于页 ===== */
.about-hero-section {
  padding: 52px 48px 44px;
  background: linear-gradient(135deg, var(--dark), var(--dark-mid));
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 40px;
  align-items: center;
  position: relative;
  overflow: hidden;
}

.about-bg-num {
  position: absolute;
  font-family: var(--font-hand);
  font-size: 10rem;
  font-weight: 700;
  color: rgba(92, 198, 176, 0.05);
  top: 50%;
  right: 48px;
  transform: translateY(-50%);
  pointer-events: none;
  user-select: none;
  white-space: nowrap;
}

.about-hero-fig h1 {
  font-family: var(--font-hand);
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--mint);
  margin: 8px 0 14px;
  line-height: 1.3;
}

.about-intro {
  font-size: 1rem;
  color: var(--sand);
  line-height: 1.75;
  max-width: 600px;
}

.about-aside-top {
  display: flex;
  flex-direction: column;
  gap: 14px;
  z-index: 1;
}

.about-stat-box {
  padding: 18px 24px;
  text-align: center;
  min-width: 120px;
}

.stat-num {
  display: block;
  font-family: var(--font-hand);
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--mint);
  line-height: 1.1;
}

.stat-label {
  display: block;
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.about-content-section {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 40px;
  padding: 48px 48px 60px;
  align-items: start;
}

.about-content {
  max-width: 720px;
}

/* ===== 隐私页 ===== */
.privacy-header-section {
  padding: 52px 48px 40px;
  background: linear-gradient(135deg, var(--dark), var(--dark-mid));
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 40px;
  align-items: start;
}

.privacy-header-fig h1 {
  font-family: var(--font-hand);
  font-size: 2rem;
  font-weight: 700;
  color: var(--mint);
  margin: 8px 0 12px;
  line-height: 1.3;
}

.privacy-header-fig p {
  color: var(--sand);
  line-height: 1.7;
  max-width: 560px;
  margin-bottom: 12px;
}

.privacy-header-fig time {
  font-size: 0.82rem;
  color: var(--text-muted);
  display: block;
}

.privacy-aside-top {
  min-width: 200px;
}

.privacy-notice {
  padding: 20px;
}

.privacy-notice p {
  font-size: 0.88rem;
  color: var(--sand);
  line-height: 1.6;
}

.privacy-content-section {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 40px;
  padding: 48px 48px 60px;
  align-items: start;
}

.privacy-content {
  max-width: 720px;
}

/* ===== 默认页 ===== */
.default-header-section {
  padding: 48px 48px 36px;
  background: linear-gradient(135deg, var(--dark), var(--dark-mid));
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.default-header-fig h1 {
  font-family: var(--font-hand);
  font-size: 2rem;
  font-weight: 700;
  color: var(--mint);
  margin: 8px 0 12px;
}

.default-header-fig p {
  color: var(--sand);
  line-height: 1.7;
}

.default-aside-top a {
  color: var(--mint);
  text-decoration: none;
  font-size: 0.9rem;
}

.default-content-section {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 40px;
  padding: 48px 48px 60px;
  align-items: start;
}

.default-content {
  max-width: 720px;
}

/* ===== Stagger 动画 ===== */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(18px); }
  to { opacity: 1; transform: translateY(0); }
}

.card {
  animation: fadeInUp 0.5s ease-out both;
}

.articles-grid .card:nth-child(1) { animation-delay: 0.05s; }
.articles-grid .card:nth-child(2) { animation-delay: 0.10s; }
.articles-grid .card:nth-child(3) { animation-delay: 0.15s; }
.articles-grid .card:nth-child(4) { animation-delay: 0.20s; }
.articles-grid .card:nth-child(5) { animation-delay: 0.25s; }
.articles-grid .card:nth-child(6) { animation-delay: 0.30s; }

.child-block {
  animation: fadeInUp 0.4s ease-out both;
}

.children-grid .child-block:nth-child(1) { animation-delay: 0.05s; }
.children-grid .child-block:nth-child(2) { animation-delay: 0.10s; }
.children-grid .child-block:nth-child(3) { animation-delay: 0.15s; }
.children-grid .child-block:nth-child(4) { animation-delay: 0.20s; }
.children-grid .child-block:nth-child(5) { animation-delay: 0.25s; }
.children-grid .child-block:nth-child(6) { animation-delay: 0.30s; }

/* ===== 移动端断点 ===== */
@media (max-width: 900px) {
  :root {
    --nav-width: 0px;
  }

  .side-nav {
    position: fixed;
    left: -280px;
    width: 260px;
    transition: left var(--transition);
    z-index: 200;
  }

  .side-nav.open {
    left: 0;
  }

  .page-body {
    margin-left: 0;
  }

  .mobile-nav-toggle {
    display: flex;
  }

  .hero-section {
    grid-template-columns: 1fr;
    min-height: auto;
    padding: 60px 24px 40px;
  }

  .hero-aside {
    order: 2;
  }

  .hero-content {
    order: 1;
    text-align: left;
  }

  .hero-imgs {
    width: 280px;
    height: 300px;
  }

  .hero-img-wrap-a,
  .hero-placeholder-a {
    width: 180px;
    height: 220px;
  }

  .hero-img-wrap-b,
  .hero-placeholder-b {
    width: 160px;
    height: 190px;
  }

  .topics-section,
  .articles-section {
    padding: 40px 24px;
  }

  .topic-content-section,
  .article-body-section,
  .tag-content-section,
  .about-content-section,
  .privacy-content-section,
  .default-content-section {
    grid-template-columns: 1fr;
    padding: 32px 24px 48px;
  }

  .topic-aside,
  .article-aside,
  .tag-aside,
  .about-aside,
  .privacy-aside,
  .default-aside {
    position: static;
  }

  .topic-hero,
  .article-header-section,
  .tag-header-section,
  .about-hero-section,
  .privacy-header-section,
  .default-header-section {
    padding: 48px 24px 32px;
    grid-template-columns: 1fr;
  }

  .about-bg-num {
    display: none;
  }

  .about-aside-top {
    flex-direction: row;
    flex-wrap: wrap;
  }

  .article-header-fig {
    grid-template-columns: 1fr;
  }

  footer {
    padding: 32px 24px 20px;
  }

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

  .hero-h1 {
    font-size: 1.8rem;
  }
}

@media (max-width: 600px) {
  html { font-size: 16px; }

  .topics-grid,
  .articles-grid,
  .children-grid {
    grid-template-columns: 1fr;
  }

  .hero-imgs {
    display: none;
  }

  .hero-section {
    min-height: 60vh;
    padding: 52px 20px 36px;
  }

  .hero-h1 {
    font-size: 1.6rem;
  }
}

/* ===== 移动端导航按钮 ===== */
.mobile-nav-toggle {
  display: none;
  position: fixed;
  top: 14px;
  left: 14px;
  z-index: 300;
  background: var(--dark-mid);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  flex-direction: column;
  gap: 5px;
  padding: 10px;
}

.mobile-nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--mint);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

.mobile-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(23, 38, 35, 0.6);
  z-index: 150;
  backdrop-filter: blur(2px);
}

.mobile-overlay.active {
  display: block;
}

@media (max-width: 900px) {
  .mobile-nav-toggle {
    display: flex;
  }
}

/* ===== prefers-reduced-motion ===== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation: none !important;
    transition: none !important;
  }
}