/* ============================================================
   UC赛场 — /assets/site.css
   共享外壳：轨道导航 + 页脚 + 通用组件
   ============================================================ */

:root {
  --ink-900: #071C18;
  --ink-800: #0C2A24;
  --ink-700: #0E312A;
  --line: #1E3F38;
  --cyan: #35F0D0;
  --mist: #8FF7E4;
  --amber: #FFB347;
  --rose: #FF3D7F;
  --violet: #7A5CFF;
  --paper: #EAF6F2;
  --slate: #6E8C85;
  --text-soft: #C9DED8;

  --rail: 92px;
  --header-h: 64px;
  --gutter: 48px;
  --maxw: 1280px;

  --r-lg: 24px;
  --r-md: 18px;
  --r-sm: 12px;

  --ease: cubic-bezier(.22, .68, .24, 1);
  --t: 200ms;

  --font-sans: "Source Han Sans SC", "Noto Sans SC", "Alibaba PuHuiTi", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  color-scheme: dark;
}

body {
  margin: 0;
  padding-inline-start: var(--rail);
  background: var(--ink-900);
  color: var(--text-soft);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6, p, figure, blockquote, dl, dd { margin: 0; }

h1, h2, h3, h4 {
  font-family: var(--font-sans);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  color: var(--paper);
}

h1 { font-size: clamp(38px, 5.2vw, 68px); letter-spacing: -0.045em; }
h2 { font-size: clamp(26px, 3vw, 36px); }
h3 { font-size: 22px; }
h4 { font-size: 18px; }

a { color: var(--cyan); text-decoration: none; }
img, svg, video, canvas { max-width: 100%; }
ul, ol { margin: 0; padding: 0; }
button { font-family: inherit; }
table { border-collapse: collapse; width: 100%; }

::selection { background: rgba(53, 240, 208, .28); color: var(--paper); }

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 4px;
}

#main-content { scroll-margin-top: 80px; }

/* ---------- 工具类 ---------- */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.container--narrow { max-width: 860px; }

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: .02em;
}

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  margin: -1px; padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.rule {
  height: 1px;
  border: 0;
  margin: 0;
  background: linear-gradient(90deg, var(--cyan), rgba(53, 240, 208, 0) 72%);
}

/* ---------- skip link ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 200;
  padding: 11px 20px;
  border-radius: 999px;
  background: var(--cyan);
  color: #04201B;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  transform: translateY(-180%);
  transition: transform 180ms var(--ease);
}

.skip-link:focus {
  transform: translateY(0);
  outline-offset: 4px;
}

/* ============================================================
   头部 / 左侧轨道导航
   ============================================================ */
.site-header {
  position: fixed;
  inset-block: 0;
  inset-inline-start: 0;
  z-index: 60;
  width: var(--rail);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding: 22px 10px 18px;
  background:
    linear-gradient(180deg, #0C2A24 0%, #09211C 55%, #071C18 100%);
  border-inline-end: 1px solid var(--line);
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: var(--rail);
  right: 0;
  height: 2px;
  z-index: 8;
  background: rgba(30, 63, 56, .55);
  pointer-events: none;
}

.scroll-progress__fill {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--cyan) 0%, var(--mist) 55%, var(--amber) 100%);
  transition: width 120ms linear;
}

.site-header__bar {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  flex: 0 0 auto;
}

/* 品牌 */
.brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--paper);
}

.brand__logo {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: 13px;
  background: var(--cyan);
  color: #052722;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.05em;
  box-shadow: 0 0 0 1px rgba(53, 240, 208, .4), 0 0 22px rgba(53, 240, 208, .28);
  transition: background-color var(--t) var(--ease), box-shadow var(--t) var(--ease);
}

.brand:hover .brand__logo,
.brand:focus-visible .brand__logo {
  background: var(--mist);
  box-shadow: 0 0 0 1px var(--mist), 0 0 30px rgba(53, 240, 208, .5);
}

.brand__name {
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .02em;
  line-height: 1.2;
  text-align: center;
  color: var(--paper);
}

/* 导航 */
.site-nav {
  flex: 1 1 auto;
  width: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
  overflow-x: hidden;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--line) transparent;
}

.site-nav__list {
  list-style: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  width: 100%;
}

.site-nav__link {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
  width: 100%;
  padding: 10px 4px;
  border-radius: var(--r-sm);
  color: var(--slate);
  text-decoration: none;
  text-align: center;
  transition: color var(--t) var(--ease), background-color var(--t) var(--ease);
}

.site-nav__num {
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: .12em;
  color: currentColor;
  opacity: .7;
}

.site-nav__text {
  font-size: 12px;
  line-height: 1.3;
  letter-spacing: .01em;
  font-weight: 600;
}

.site-nav__link:hover,
.site-nav__link:focus-visible {
  color: var(--paper);
  background: rgba(53, 240, 208, .08);
}

.site-nav__link[aria-current="page"] {
  color: var(--cyan);
  background: rgba(53, 240, 208, .1);
}

.site-nav__link[aria-current="page"]::before {
  content: "";
  position: absolute;
  inset-inline-start: 2px;
  top: 50%;
  translate: 0 -50%;
  width: 3px;
  height: 22px;
  border-radius: 2px;
  background: var(--cyan);
  box-shadow: 0 0 12px rgba(53, 240, 208, .65);
}

/* 轨道底部读数 */
.rail-foot {
  flex: 0 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  padding-block-end: 2px;
}

.rail-foot__dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--rose);
  animation: uc-pulse 2.6s ease-in-out infinite;
}

.rail-foot__clock {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .04em;
  color: var(--amber);
}

@keyframes uc-pulse {
  0%, 100% { opacity: .45; box-shadow: 0 0 0 0 rgba(255, 61, 127, .45); }
  50% { opacity: 1; box-shadow: 0 0 0 6px rgba(255, 61, 127, 0); }
}

/* 移动端开关与遮罩（桌面隐藏） */
.nav-toggle { display: none; }
.nav-scrim { display: none; }

/* ============================================================
   页脚
   ============================================================ */
.site-footer {
  position: relative;
  margin-top: 120px;
  border-top: 1px solid var(--line);
  background:
    radial-gradient(120% 90% at 8% 0%, rgba(53, 240, 208, .09), transparent 62%),
    radial-gradient(90% 80% at 96% 10%, rgba(122, 92, 255, .1), transparent 60%),
    linear-gradient(180deg, #0A251F 0%, #061714 100%);
}

.site-footer::before {
  content: "";
  position: absolute;
  inset-inline: 0;
  top: -1px;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--cyan) 18%, var(--mist) 48%, var(--violet) 78%, transparent);
  opacity: .5;
}

.site-footer__inner {
  max-width: var(--maxw);
  margin-inline: auto;
  padding: 76px var(--gutter) 30px;
}

.footer__top {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 2fr);
  gap: 56px;
}

.footer__name {
  font-size: 25px;
  font-weight: 800;
  letter-spacing: -.03em;
  color: var(--paper);
}

.footer__tagline {
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .16em;
  color: var(--cyan);
}

.footer__summary {
  margin-top: 18px;
  max-width: 34em;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--slate);
}

.footer__cols {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 32px;
}

.footer__col-title {
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .2em;
  color: var(--cyan);
  text-transform: uppercase;
}

.footer__list {
  list-style: none;
  display: grid;
  gap: 11px;
}

.footer__link {
  position: relative;
  display: inline-block;
  color: var(--paper);
  font-size: 15px;
  text-decoration: none;
  padding-bottom: 2px;
}

.footer__link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 1px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--t) var(--ease);
}

.footer__link:hover::after,
.footer__link:focus-visible::after { transform: scaleX(1); }

.footer__contact {
  margin-top: 56px;
  padding-top: 26px;
  border-top: 1px dashed var(--line);
  display: flex;
  flex-wrap: wrap;
  gap: 6px 32px;
  font-style: normal;
  font-size: 14px;
  color: var(--slate);
}

.footer__contact-item { margin: 0; }
.footer__contact-item .mono { color: var(--mist); }

.footer__note {
  margin-top: 14px;
  font-size: 13px;
  line-height: 1.75;
  color: #55736C;
  max-width: 60em;
}

.footer__bottom {
  margin-top: 28px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px 28px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--slate);
}

.footer__bottom p { margin: 0; }
.footer__icp { color: #55736C; }

/* ============================================================
   通用组件
   ============================================================ */

/* 网格 */
.grid { display: grid; gap: 24px; }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--split { grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr); }

/* 章节标题体系 */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--cyan);
  text-transform: uppercase;
}

.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: var(--cyan);
}

.chapter { display: grid; gap: 12px; }

.chapter-num {
  font-family: var(--font-mono);
  font-size: clamp(52px, 9vw, 96px);
  font-weight: 200;
  line-height: .85;
  letter-spacing: -.05em;
  color: var(--violet);
  opacity: .6;
}

.chapter-title {
  font-size: clamp(26px, 3.4vw, 40px);
  letter-spacing: -.035em;
}

.section-head {
  display: grid;
  gap: 10px;
  margin-bottom: 32px;
}

.section-title {
  font-size: clamp(22px, 2.4vw, 30px);
  letter-spacing: -.03em;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 46px;
  padding: 0 24px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-family: inherit;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .01em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color var(--t) var(--ease),
              color var(--t) var(--ease),
              border-color var(--t) var(--ease),
              transform var(--t) var(--ease),
              box-shadow var(--t) var(--ease);
}

.btn--primary {
  background: var(--cyan);
  color: #04201B;
  box-shadow: 0 8px 26px rgba(53, 240, 208, .22);
}

.btn--primary:hover,
.btn--primary:focus-visible {
  background: var(--mist);
  transform: translateY(-2px);
}

.btn--ghost {
  background: transparent;
  border-color: var(--line);
  color: var(--paper);
}

.btn--ghost:hover,
.btn--ghost:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
  background: rgba(53, 240, 208, .07);
}

.btn--amber {
  background: transparent;
  border-color: rgba(255, 179, 71, .5);
  color: var(--amber);
}

.btn--amber:hover,
.btn--amber:focus-visible {
  border-color: var(--amber);
  background: rgba(255, 179, 71, .1);
}

.btn--sm {
  min-height: 38px;
  padding: 0 18px;
  font-size: 13.5px;
}

/* 标签 */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 4px 12px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: rgba(53, 240, 208, .05);
  color: var(--mist);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  line-height: 1.6;
  white-space: nowrap;
}

.tag--live {
  color: var(--rose);
  border-color: rgba(255, 61, 127, .42);
  background: rgba(255, 61, 127, .09);
}

.tag--amber {
  color: var(--amber);
  border-color: rgba(255, 179, 71, .4);
  background: rgba(255, 179, 71, .07);
}

.tag--violet {
  color: #B9A9FF;
  border-color: rgba(122, 92, 255, .45);
  background: rgba(122, 92, 255, .12);
}

.tag__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: currentColor;
  flex: 0 0 auto;
}

/* 胶囊筛选 */
.chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 16px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--slate);
  font-family: inherit;
  font-size: 13.5px;
  line-height: 1.5;
  cursor: pointer;
  transition: color var(--t) var(--ease),
              border-color var(--t) var(--ease),
              background-color var(--t) var(--ease);
}

.chip:hover { color: var(--paper); border-color: var(--mist); }

.chip[aria-pressed="true"],
.chip[aria-selected="true"],
.chip.is-active {
  background: rgba(53, 240, 208, .14);
  border-color: var(--cyan);
  color: var(--paper);
}

/* 卡片 */
.card {
  position: relative;
  background: var(--ink-800);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  padding: 24px;
}

.card--link {
  display: block;
  color: inherit;
  text-decoration: none;
  transition: transform var(--t) var(--ease),
              border-color var(--t) var(--ease),
              background-color var(--t) var(--ease);
}

.card--link:hover,
.card--link:focus-visible {
  transform: translateY(-2px);
  border-color: var(--cyan);
  background: var(--ink-700);
}

.card__title {
  font-size: 20px;
  letter-spacing: -.02em;
  margin-bottom: 10px;
}

.card__meta {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--slate);
}

.card__body {
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-soft);
}

/* 等宽读数条 */
.data-strip {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--line);
  font-size: 14px;
  color: var(--slate);
}

.data-strip:last-child { border-bottom: 0; }

.data-strip__value {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 17px;
  font-weight: 600;
  color: var(--paper);
  letter-spacing: -.01em;
}

.data-strip__value.is-accent { color: var(--amber); }

/* 面包屑 */
.breadcrumb {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--slate);
}

.breadcrumb ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
}

.breadcrumb li { display: inline-flex; align-items: center; gap: 8px; }

.breadcrumb li + li::before {
  content: "/";
  color: var(--line);
}

.breadcrumb a { color: var(--slate); text-decoration: none; transition: color var(--t) var(--ease); }
.breadcrumb a:hover, .breadcrumb a:focus-visible { color: var(--cyan); }
.breadcrumb [aria-current="page"] { color: var(--paper); }

/* 正文 */
.prose {
  max-width: 40em;
  font-size: 17px;
  line-height: 1.8;
  color: var(--text-soft);
}

.prose > * + * { margin-top: 1.1em; }
.prose h2 { font-size: 28px; margin-top: 2em; letter-spacing: -.03em; }
.prose h3 { font-size: 21px; margin-top: 1.8em; letter-spacing: -.02em; }
.prose ul, .prose ol { padding-inline-start: 1.25em; }
.prose li + li { margin-top: .55em; }
.prose a {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}
.prose a:hover { color: var(--mist); }
.prose strong { color: var(--paper); font-weight: 700; }
.prose code {
  font-family: var(--font-mono);
  font-size: .92em;
  padding: 2px 6px;
  border-radius: 6px;
  background: rgba(53, 240, 208, .1);
  color: var(--mist);
}
.prose blockquote {
  margin-inline: 0;
  padding-inline-start: 20px;
  border-inline-start: 2px solid var(--cyan);
  color: var(--slate);
}

/* 图片容器（页面阶段放 <img> 或占位即可） */
.media {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  border-radius: var(--r-lg);
  border: 1px solid var(--line);
  background-color: var(--ink-800);
  background-image: linear-gradient(135deg, rgba(53, 240, 208, .12), rgba(122, 92, 255, .1));
  aspect-ratio: 16 / 9;
}

.media > img,
.media > picture,
.media > picture > img,
.media > svg,
.media > video {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media--wide { aspect-ratio: 21 / 9; }
.media--tall { aspect-ratio: 3 / 4; }
.media--square { aspect-ratio: 1 / 1; }
.media--hero { aspect-ratio: 4 / 3; }

.media--pitch {
  background-image:
    repeating-linear-gradient(90deg, rgba(53, 240, 208, .08) 0 1px, transparent 1px 56px),
    repeating-linear-gradient(0deg, rgba(53, 240, 208, .08) 0 1px, transparent 1px 56px);
}

.media__overlay {
  position: absolute;
  inset-inline: 0;
  inset-block-end: 0;
  padding: 20px;
  background: linear-gradient(to top, rgba(4, 20, 17, .94), rgba(4, 20, 17, 0));
}

.media__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--cyan);
}

/* ============================================================
   响应式
   ============================================================ */

@media (max-width: 1100px) {
  :root { --gutter: 32px; }
}

@media (max-width: 1024px) and (min-width: 721px) {
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 980px) {
  .footer__top {
    grid-template-columns: minmax(0, 1fr);
    gap: 44px;
  }
}

/* ---- 移动端：赛道折成顶部横条 ---- */
@media (max-width: 899px) {
  :root { --rail: 0px; }

  body {
    padding-inline-start: 0;
    padding-block-start: var(--header-h);
  }

  .site-header {
    inset: 0 0 auto 0;
    width: 100%;
    height: var(--header-h);
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    padding: 0 16px 0 18px;
    border-inline-end: 0;
    border-bottom: 1px solid var(--line);
    background: rgba(7, 28, 24, .97);
  }

  .site-header[data-scrolled="true"] {
    box-shadow: 0 10px 26px rgba(0, 0, 0, .5);
  }

  .site-header__bar {
    width: auto;
    justify-content: flex-start;
    flex: 0 1 auto;
    min-width: 0;
  }

  .brand {
    flex-direction: row;
    align-items: center;
    gap: 10px;
  }

  .brand__logo {
    width: 34px;
    height: 34px;
    border-radius: 10px;
    font-size: 13px;
  }

  .brand__name {
    font-size: 15px;
    letter-spacing: .01em;
  }

  /* 开关 */
  .nav-toggle {
    display: inline-flex;
    align-items: center;
    gap: 9px;
    min-height: 40px;
    padding: 0 15px;
    border-radius: 999px;
    border: 1px solid var(--line);
    background: rgba(53, 240, 208, .07);
    color: var(--paper);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    z-index: 66;
    position: relative;
    transition: border-color var(--t) var(--ease), background-color var(--t) var(--ease);
  }

  .nav-toggle:hover,
  .nav-toggle:focus-visible {
    border-color: var(--cyan);
    background: rgba(53, 240, 208, .14);
  }

  .nav-toggle__bars {
    display: grid;
    gap: 3px;
    width: 16px;
  }

  .nav-toggle__bars i {
    display: block;
    width: 16px;
    height: 2px;
    border-radius: 2px;
    background: var(--cyan);
    transition: transform var(--t) var(--ease), opacity var(--t) var(--ease);
  }

  .site-header[data-open="true"] .nav-toggle__bars i:nth-child(1) {
    transform: translateY(5px) rotate(45deg);
  }

  .site-header[data-open="true"] .nav-toggle__bars i:nth-child(2) {
    opacity: 0;
  }

  .site-header[data-open="true"] .nav-toggle__bars i:nth-child(3) {
    transform: translateY(-5px) rotate(-45deg);
  }

  /* 抽屉 */
  .site-nav {
    position: fixed;
    inset-block: 0;
    inset-inline-end: 0;
    width: min(324px, 86vw);
    flex: 0 0 auto;
    justify-content: flex-start;
    padding: 82px 20px 28px;
    background: linear-gradient(180deg, #0C2A24 0%, #071C18 100%);
    border-inline-start: 1px solid var(--line);
    transform: translateX(101%);
    visibility: hidden;
    transition: transform 220ms var(--ease), visibility 220ms var(--ease);
    z-index: 65;
    overflow-y: auto;
    overscroll-behavior: contain;
  }

  .site-header[data-open="true"] .site-nav,
  .site-nav[data-open="true"] {
    transform: translateX(0);
    visibility: visible;
  }

  .site-nav__list {
    align-items: stretch;
    gap: 4px;
  }

  .site-nav__link {
    flex-direction: row;
    align-items: center;
    gap: 14px;
    padding: 14px 14px;
    border-radius: 14px;
    font-size: 15px;
    text-align: start;
  }

  .site-nav__num {
    font-size: 11px;
    opacity: .85;
    flex: 0 0 22px;
  }

  .site-nav__text { font-size: 15px; font-weight: 600; }

  .site-nav__link[aria-current="page"]::before {
    inset-inline-start: 0;
    width: 3px;
    height: 26px;
  }

  /* 遮罩 */
  .nav-scrim {
    display: block;
    position: fixed;
    inset: 0;
    z-index: 62;
    border: 0;
    padding: 0;
    margin: 0;
    background: rgba(3, 14, 11, .72);
    opacity: 0;
    visibility: hidden;
    cursor: pointer;
    transition: opacity 200ms var(--ease), visibility 200ms var(--ease);
  }

  .site-header[data-open="true"] .nav-scrim {
    opacity: 1;
    visibility: visible;
  }

  .rail-foot { display: none; }

  html.is-nav-open { overflow: hidden; }

  /* 页脚 */
  .site-footer { margin-top: 72px; }
  .site-footer__inner { padding: 56px var(--gutter) 26px; }
  .footer__contact { margin-top: 40px; padding-top: 22px; gap: 8px 24px; }
  .footer__bottom { font-size: 11.5px; }
}

@media (max-width: 720px) {
  body { font-size: 16px; }

  .grid--2,
  .grid--3,
  .grid--split { grid-template-columns: minmax(0, 1fr); }

  .media,
  .media--wide,
  .media--hero { aspect-ratio: 4 / 3; }

  .card { padding: 20px; border-radius: var(--r-md); }
}

@media (max-width: 620px) {
  :root { --gutter: 20px; }

  .footer__cols { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 30px 20px; }
  .footer__summary { font-size: 14px; }
  .footer__bottom { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 420px) {
  .footer__cols { grid-template-columns: minmax(0, 1fr); }
}

/* ============================================================
   可访问性
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
    scroll-behavior: auto !important;
  }

  .rail-foot__dot { animation: none; opacity: .9; }
  .scroll-progress__fill { transition: none; }
}