@import url('https://fonts.googleapis.com/css2?family=Manrope:wght@300;400;500;600;700&family=Syne:wght@400;500;600;700&display=swap');

/* ===== 基础变量 ===== */
:root {
  --c-black: #000000;
  --c-white: #ffffff;
  --c-accent: #000000;
  --c-gray-100: #f5f5f5;
  --c-gray-200: #e8e8e8;
  --c-gray-400: #999999;
  --c-gray-600: #555555;
  --c-gray-800: #222222;
  --c-line: #000000;

  --font-display: 'Syne', 'Helvetica Neue', Helvetica, Arial, sans-serif;
  --font-body: 'Manrope', 'Helvetica Neue', Helvetica, Arial, sans-serif;

  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-5: 40px;
  --space-6: 48px;
  --space-8: 64px;
  --space-10: 80px;
  --space-12: 96px;

  --radius-card: 28px;
  --sidenav-w: 240px;
  --announce-h: 36px;

  --transition-base: 0.2s ease;
}

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

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

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--c-black);
  background: var(--c-white);
  overflow-x: hidden;
}

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

a {
  color: var(--c-black);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

ul, ol {
  list-style: none;
}

dl, dt, dd {
  margin: 0;
  padding: 0;
}

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

/* ===== 左侧竖排导航 ===== */
.sidenav {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidenav-w);
  height: 100vh;
  background: var(--c-black);
  color: var(--c-white);
  display: flex;
  flex-direction: column;
  z-index: 100;
  overflow-y: auto;
  padding-bottom: var(--space-4);
}

.sidenav__brand {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: var(--space-4) var(--space-3);
  border-bottom: 1px solid rgba(255,255,255,0.12);
  gap: var(--space-2);
}

.sidenav__logo-img {
  width: 40px;
  height: 40px;
  object-fit: contain;
}

.sidenav__brand-text {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.8rem;
  line-height: 1.3;
  color: var(--c-white);
  letter-spacing: 0.02em;
  word-break: break-all;
}

.sidenav__nav {
  padding: var(--space-3) 0;
  flex: 1;
}

.sidenav__nav dl {
  display: flex;
  flex-direction: column;
}

.sidenav__nav-label {
  font-family: var(--font-display);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.35);
  padding: 0 var(--space-3) var(--space-1);
}

.sidenav__nav dd {
  margin: 0;
}

.sidenav__link {
  display: block;
  padding: 12px var(--space-3);
  font-size: 0.82rem;
  font-weight: 500;
  color: rgba(255,255,255,0.75);
  line-height: 1.4;
  transition: background var(--transition-base), color var(--transition-base);
  border-left: 3px solid transparent;
  min-height: 40px;
  display: flex;
  align-items: center;
}

.sidenav__link:hover,
.sidenav__link:focus {
  color: var(--c-white);
  background: rgba(255,255,255,0.08);
  border-left-color: var(--c-white);
  text-decoration: none;
}

/* ===== 主内容区 ===== */
.main-wrap {
  margin-left: var(--sidenav-w);
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

/* ===== 公告条 ===== */
.announce-bar {
  height: var(--announce-h);
  background: var(--c-black);
  color: var(--c-white);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  font-family: var(--font-display);
  flex-shrink: 0;
}

/* ===== main / article / section 三层 ===== */
main {
  flex: 1;
}

main > article {
  display: flex;
  flex-direction: column;
}

main > article > section {
  width: 100%;
}

/* ===== Hero 首页 ===== */
.hero--home {
  position: relative;
  min-height: calc(100vh - var(--announce-h));
  background: var(--c-black);
  color: var(--c-white);
  display: flex;
  align-items: center;
  overflow: hidden;
  clip-path: polygon(0 0, 100% 0, 100% 88%, 0 100%);
  padding: var(--space-12) var(--space-8) calc(var(--space-12) + 60px);
}

.hero__bg-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.04) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
}

.hero__content {
  position: relative;
  z-index: 2;
  max-width: 720px;
}

.hero__eyebrow {
  font-family: var(--font-display);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: rgba(255,255,255,0.5);
  margin-bottom: var(--space-2);
}

.hero--home h1 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 4rem);
  font-weight: 700;
  line-height: 1.1;
  color: var(--c-white);
  margin-bottom: var(--space-3);
  letter-spacing: -0.02em;
}

.hero__lead {
  font-size: 1.1rem;
  line-height: 1.7;
  color: rgba(255,255,255,0.65);
  max-width: 560px;
  margin-bottom: var(--space-5);
}

.hero__actions {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.hero__slant {
  display: none;
}

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px var(--space-4);
  font-family: var(--font-display);
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  border-radius: 100px;
  cursor: pointer;
  min-height: 48px;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  text-decoration: none;
}

.btn:hover {
  transform: translateY(-1px);
  text-decoration: none;
}

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

.btn--primary:hover {
  box-shadow: 0 4px 16px rgba(255,255,255,0.25);
}

.btn--outline {
  background: transparent;
  color: var(--c-white);
  border: 2px solid rgba(255,255,255,0.5);
}

.btn--outline:hover {
  border-color: var(--c-white);
}

/* ===== 页面内部 Hero（非首页） ===== */
.page-hero {
  background: var(--c-black);
  color: var(--c-white);
  padding: var(--space-8) var(--space-8) var(--space-8);
  clip-path: polygon(0 0, 100% 0, 100% 90%, 0 100%);
  margin-bottom: var(--space-6);
}

.page-hero__inner {
  max-width: 800px;
}

.page-hero__eyebrow {
  font-family: var(--font-display);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: rgba(255,255,255,0.45);
  margin-bottom: var(--space-2);
}

.page-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 3.5vw, 2.8rem);
  font-weight: 700;
  line-height: 1.15;
  color: var(--c-white);
  margin-bottom: var(--space-2);
  letter-spacing: -0.02em;
}

.page-hero__desc {
  font-size: 1rem;
  color: rgba(255,255,255,0.6);
  line-height: 1.7;
  max-width: 600px;
}

.page-hero__date {
  display: block;
  font-size: 0.8rem;
  color: rgba(255,255,255,0.45);
  margin-bottom: var(--space-2);
}

/* ===== 内容区 ===== */
.content-section {
  padding: var(--space-6) var(--space-8);
  max-width: 1280px;
  margin: 0 auto;
  width: 100%;
}

.section-header {
  margin-bottom: var(--space-5);
  border-bottom: 2px solid var(--c-black);
  padding-bottom: var(--space-2);
}

.section-header h2 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.section-header h2 span {
  display: inline;
}

/* ===== 带侧边栏布局 ===== */
.layout-with-aside {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: var(--space-6);
  align-items: start;
}

.content-aside {
  position: sticky;
  top: calc(var(--announce-h) + var(--space-3));
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.aside-block {
  border: 1px solid var(--c-gray-200);
  border-radius: 12px;
  padding: var(--space-3);
}

.aside-block h3 {
  font-family: var(--font-display);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--c-gray-600);
  margin-bottom: var(--space-2);
  border-bottom: 1px solid var(--c-gray-200);
  padding-bottom: var(--space-1);
}

.aside-block h3 span {
  display: inline;
}

.aside-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.aside-list li a {
  display: block;
  padding: 6px 8px;
  font-size: 0.82rem;
  color: var(--c-gray-800);
  border-radius: 6px;
  transition: background var(--transition-base);
  min-height: 32px;
  display: flex;
  align-items: center;
}

.aside-list li a:hover {
  background: var(--c-gray-100);
  text-decoration: none;
}

.content-main {
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

/* ===== 卡片 ===== */
.grid-cards {
  display: grid;
  gap: var(--space-3);
}

.grid-cards--4 {
  grid-template-columns: repeat(4, 1fr);
}

.grid-cards--3 {
  grid-template-columns: repeat(3, 1fr);
}

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

.card {
  border-radius: var(--radius-card);
  border: 1px solid var(--c-gray-200);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  background: var(--c-white);
  position: relative;
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(0,0,0,0.1);
}

.card__inner {
  padding: var(--space-4);
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.card__eyebrow {
  font-family: var(--font-display);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  color: var(--c-gray-400);
}

.card h3 {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.3;
  margin: 0;
}

.card h3 span {
  display: inline;
}

.card__desc {
  font-size: 0.875rem;
  color: var(--c-gray-600);
  line-height: 1.6;
  flex: 1;
}

.card__date {
  font-size: 0.75rem;
  color: var(--c-gray-400);
}

.card__meta {
  font-size: 0.78rem;
  color: var(--c-gray-600);
}

.card__meta a {
  font-weight: 600;
}

.card__cta {
  display: inline-flex;
  align-items: center;
  padding: 8px 16px;
  background: var(--c-black);
  color: var(--c-white);
  font-family: var(--font-display);
  font-size: 0.78rem;
  font-weight: 700;
  border-radius: 100px;
  letter-spacing: 0.05em;
  align-self: flex-start;
  transition: opacity var(--transition-base);
  min-height: 40px;
}

.card__cta:hover {
  opacity: 0.8;
  text-decoration: none;
}

.card__line {
  height: 4px;
  background: var(--c-black);
  border-radius: 0 0 var(--radius-card) var(--radius-card);
}

/* ===== 正文内容 ===== */
.page-content-area {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--c-gray-800);
}

.page-content-area h2 {
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 700;
  margin: var(--space-5) 0 var(--space-2);
  color: var(--c-black);
  letter-spacing: -0.01em;
}

.page-content-area h2 span {
  display: inline;
}

.page-content-area h3 {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  margin: var(--space-4) 0 var(--space-2);
  color: var(--c-black);
}

.page-content-area h3 span {
  display: inline;
}

.page-content-area p {
  margin-bottom: var(--space-3);
}

.page-content-area ul,
.page-content-area ol {
  padding-left: var(--space-3);
  margin-bottom: var(--space-3);
  list-style: disc;
}

.page-content-area ol {
  list-style: decimal;
}

.page-content-area li {
  margin-bottom: var(--space-1);
}

.page-content-area a {
  color: var(--c-black);
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-content-area a:hover {
  opacity: 0.7;
}

.page-content-area table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--space-3);
  font-size: 0.9rem;
}

.page-content-area th,
.page-content-area td {
  padding: 8px 12px;
  border: 1px solid var(--c-gray-200);
  text-align: left;
}

.page-content-area th {
  background: var(--c-gray-100);
  font-weight: 700;
}

.page-content-area blockquote {
  border-left: 4px solid var(--c-black);
  padding-left: var(--space-3);
  color: var(--c-gray-600);
  margin: var(--space-3) 0;
}

/* ===== 频道页列表 ===== */
.channel-list h2,
.tag-list-wrap h2 {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: var(--space-3);
  padding-bottom: var(--space-2);
  border-bottom: 2px solid var(--c-black);
}

.channel-list h2 span,
.tag-list-wrap h2 span {
  display: inline;
}

.channel-dl,
.tag-dl {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.channel-item,
.tag-item {
  display: grid;
  grid-template-columns: 1fr;
  border-bottom: 1px solid var(--c-gray-200);
  padding: var(--space-3) 0;
  gap: var(--space-1);
}

.channel-item dt a,
.tag-item dt a {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  color: var(--c-black);
  transition: opacity var(--transition-base);
}

.channel-item dt a:hover,
.tag-item dt a:hover {
  opacity: 0.65;
  text-decoration: none;
}

.channel-item dd,
.tag-item dd {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  align-items: baseline;
}

.channel-item__date,
.tag-item__date {
  font-size: 0.75rem;
  color: var(--c-gray-400);
  font-family: var(--font-display);
}

.channel-item__desc,
.tag-item__desc {
  font-size: 0.875rem;
  color: var(--c-gray-600);
  line-height: 1.5;
}

/* ===== 文章页 ===== */
.article-header-section {
  background: var(--c-black);
  color: var(--c-white);
  padding: var(--space-8) var(--space-8) var(--space-6);
  clip-path: polygon(0 0, 100% 0, 100% 92%, 0 100%);
  margin-bottom: var(--space-5);
}

.article-header {
  max-width: 800px;
}

.breadcrumb {
  font-size: 0.78rem;
  color: rgba(255,255,255,0.45);
  margin-bottom: var(--space-3);
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

.breadcrumb a {
  color: rgba(255,255,255,0.55);
}

.breadcrumb a:hover {
  color: var(--c-white);
  text-decoration: none;
}

.article-header h1 {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 3vw, 2.6rem);
  font-weight: 700;
  line-height: 1.15;
  color: var(--c-white);
  margin-bottom: var(--space-3);
  letter-spacing: -0.02em;
}

.article-meta {
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap;
  margin-bottom: var(--space-2);
}

.article-date {
  font-family: var(--font-display);
  font-size: 0.78rem;
  color: rgba(255,255,255,0.45);
}

.article-date--mod {
  color: rgba(255,255,255,0.35);
}

.article-lead {
  font-size: 1rem;
  color: rgba(255,255,255,0.6);
  line-height: 1.7;
  max-width: 600px;
}

.article-hero-wrap {
  margin-top: var(--space-4);
  border-radius: 12px;
  overflow: hidden;
}

.article-hero-img {
  width: 100%;
  height: auto;
}

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

.article-footer-links h2 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: var(--space-3);
  padding-bottom: var(--space-2);
  border-bottom: 2px solid var(--c-black);
}

.article-footer-links h2 span {
  display: inline;
}

/* ===== About 页 ===== */
.about-body {
  max-width: 720px;
}

.about-nav-links h2 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: var(--space-3);
  border-bottom: 2px solid var(--c-black);
  padding-bottom: var(--space-2);
}

.about-nav-links h2 span {
  display: inline;
}

/* ===== Privacy 页 ===== */
.privacy-body {
  max-width: 720px;
}

.privacy-links h2 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: var(--space-3);
  border-bottom: 2px solid var(--c-black);
  padding-bottom: var(--space-2);
}

.privacy-links h2 span {
  display: inline;
}

.link-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  list-style: none;
}

.link-list li a {
  display: inline-flex;
  align-items: center;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--c-black);
  text-decoration: underline;
  text-underline-offset: 3px;
  min-height: 40px;
}

/* ===== 页脚 ===== */
.site-footer {
  background: var(--c-black);
  color: var(--c-white);
  padding: var(--space-8) var(--space-8) var(--space-4);
  margin-top: var(--space-8);
}

.footer__cols {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-5);
  margin-bottom: var(--space-6);
  padding-bottom: var(--space-6);
  border-bottom: 1px solid rgba(255,255,255,0.12);
}

.footer__col dt {
  font-family: var(--font-display);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: rgba(255,255,255,0.4);
  margin-bottom: var(--space-2);
}

.footer__col dd {
  margin-bottom: 6px;
}

.footer__col dd a {
  font-size: 0.85rem;
  color: rgba(255,255,255,0.65);
  transition: color var(--transition-base);
  min-height: 28px;
  display: inline-flex;
  align-items: center;
}

.footer__col dd a:hover {
  color: var(--c-white);
  text-decoration: none;
}

.footer__nav-dl {
  margin-bottom: var(--space-5);
  padding-bottom: var(--space-5);
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer__nav-dl dl {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1) var(--space-3);
  align-items: center;
}

.footer__nav-dl dt {
  font-family: var(--font-display);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: rgba(255,255,255,0.3);
  margin-right: var(--space-1);
}

.footer__nav-dl dd {
  margin: 0;
}

.footer__nav-dl dd a {
  font-size: 0.8rem;
  color: rgba(255,255,255,0.5);
  padding: 6px 10px;
  border-radius: 100px;
  border: 1px solid rgba(255,255,255,0.15);
  transition: all var(--transition-base);
  display: inline-flex;
  align-items: center;
  min-height: 32px;
}

.footer__nav-dl dd a:hover {
  color: var(--c-white);
  border-color: rgba(255,255,255,0.5);
  text-decoration: none;
}

.footer__bottom {
  font-family: var(--font-display);
  font-size: 0.75rem;
  color: rgba(255,255,255,0.3);
  text-align: center;
}

/* ===== Scroll Reveal 动效 ===== */
@media (prefers-reduced-motion: no-preference) {
  .card,
  .channel-item,
  .tag-item,
  .aside-block {
    opacity: 0;
    transform: translateY(16px);
    transition: opacity 0.4s ease, transform 0.4s ease;
  }

  .card.revealed,
  .channel-item.revealed,
  .tag-item.revealed,
  .aside-block.revealed {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ===== 响应式 ===== */
@media (max-width: 1200px) {
  .grid-cards--4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .content-section {
    padding: var(--space-5) var(--space-5);
  }
}

@media (max-width: 1024px) {
  :root {
    --sidenav-w: 200px;
  }

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

  .grid-cards--3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --sidenav-w: 0px;
  }

  .sidenav {
    position: fixed;
    top: 0;
    left: -260px;
    width: 260px;
    transition: left 0.3s ease;
    z-index: 200;
  }

  .sidenav.open {
    left: 0;
  }

  .main-wrap {
    margin-left: 0;
  }

  .announce-bar {
    font-size: 0.72rem;
    padding: 0 var(--space-2);
    text-align: center;
    height: auto;
    min-height: var(--announce-h);
    padding: 8px var(--space-2);
  }

  .mobile-nav-toggle {
    display: flex;
    position: fixed;
    bottom: var(--space-4);
    right: var(--space-4);
    width: 52px;
    height: 52px;
    background: var(--c-black);
    color: var(--c-white);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    z-index: 300;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
    box-shadow: 0 4px 16px rgba(0,0,0,0.3);
  }

  .hero--home {
    min-height: 100svh;
    padding: var(--space-8) var(--space-3) calc(var(--space-8) + 48px);
    clip-path: polygon(0 0, 100% 0, 100% 92%, 0 100%);
  }

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

  .hero__lead {
    font-size: 0.95rem;
  }

  .page-hero {
    padding: var(--space-6) var(--space-3) var(--space-5);
    clip-path: polygon(0 0, 100% 0, 100% 94%, 0 100%);
  }

  .page-hero h1 {
    font-size: 1.5rem;
  }

  .content-section {
    padding: var(--space-4) var(--space-3);
  }

  .layout-with-aside {
    grid-template-columns: 1fr;
  }

  .content-aside {
    position: static;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-2);
  }

  .grid-cards--4,
  .grid-cards--3,
  .grid-cards--2 {
    grid-template-columns: 1fr;
  }

  .footer__cols {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
  }

  .article-header-section {
    padding: var(--space-6) var(--space-3) var(--space-5);
    clip-path: polygon(0 0, 100% 0, 100% 94%, 0 100%);
  }

  .article-header h1 {
    font-size: 1.5rem;
  }

  .site-footer {
    padding: var(--space-6) var(--space-3) var(--space-3);
  }

  .footer__nav-dl dl {
    gap: 6px;
  }
}

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

  .content-aside {
    grid-template-columns: 1fr;
  }

  .hero__actions {
    flex-direction: column;
  }

  .btn {
    width: 100%;
    justify-content: center;
  }
}

/* ===== 移动端导航覆盖层 ===== */
.nav-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 150;
}

.nav-overlay.open {
  display: block;
}