/* ==========================================================================
   8868赛事 · /assets/site.css
   共享外壳：令牌 / 重置 / 中文排版 / 头部 / 页脚 / 通用组件
   ========================================================================== */

:root{
  /* 底色与面层 */
  --ink-900:#060B14;
  --ink-850:#0A1220;
  --ink-800:#0D1726;
  --ink-700:#111F33;
  --line:#1B3B63;
  --line-soft:rgba(27,59,99,.55);
  --line-faint:rgba(27,59,99,.32);

  /* 强调色 */
  --cyan:#17E0C8;
  --cyan-soft:rgba(23,224,200,.14);
  --cyan-line:rgba(23,224,200,.45);
  --orange:#FF7A2F;
  --orange-soft:rgba(255,122,47,.14);
  --green:#3DD68C;

  /* 文字 */
  --paper:#E8EEF6;
  --paper-soft:rgba(232,238,246,.84);
  --muted:#8FA3B8;
  --muted-dim:rgba(143,163,184,.68);
  --glass:rgba(232,238,246,.08);
  --glass-line:rgba(232,238,246,.16);

  /* 字体 */
  --font-head:"Barlow Condensed","Oswald","Saira Condensed","Arial Narrow","PingFang SC","HarmonyOS Sans SC","Microsoft YaHei",sans-serif;
  --font-body:"Inter","Source Han Sans SC","Noto Sans SC","PingFang SC","HarmonyOS Sans SC","Microsoft YaHei",sans-serif;
  --font-mono:"JetBrains Mono","Roboto Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,"Courier New",monospace;

  /* 尺度 */
  --shell:1320px;
  --gutter:clamp(16px,4vw,40px);
  --header-h:86px;
  --header-h-condensed:64px;
  --radius:2px;
  --ease:cubic-bezier(.22,.61,.36,1);
  --dur:.2s;
}

/* --------------------------------------------------------------------------
   1. 重置
   -------------------------------------------------------------------------- */
*,
*::before,
*::after{box-sizing:border-box;}

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

body,
h1,h2,h3,h4,h5,p,ol,ul,li,figure,blockquote,dl,dd{
  margin:0;
}

ol,ul{
  padding:0;
  list-style:none;
}

img,picture,svg,video{
  display:block;
  max-width:100%;
}

button{
  font:inherit;
  color:inherit;
  border:0;
  background:none;
}

a{
  color:inherit;
  text-decoration:none;
}

table{
  border-collapse:collapse;
  width:100%;
}

/* --------------------------------------------------------------------------
   2. 页面基底与蓝图网格
   -------------------------------------------------------------------------- */
body{
  min-height:100vh;
  background-color:var(--ink-900);
  background-image:radial-gradient(120% 70% at 50% -10%,rgba(23,224,200,.07),transparent 62%);
  color:var(--paper);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.75;
  letter-spacing:.005em;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  overflow-x:hidden;
}

/* 全站蓝图网格：向上淡出，不干扰长文 */
body::before{
  content:"";
  position:fixed;
  inset:0;
  z-index:0;
  pointer-events:none;
  background-image:
    linear-gradient(rgba(27,59,99,.42) 1px,transparent 1px),
    linear-gradient(90deg,rgba(27,59,99,.42) 1px,transparent 1px),
    linear-gradient(rgba(27,59,99,.72) 1px,transparent 1px),
    linear-gradient(90deg,rgba(27,59,99,.72) 1px,transparent 1px);
  background-size:32px 32px,32px 32px,160px 160px,160px 160px;
  opacity:.42;
  -webkit-mask-image:linear-gradient(to bottom,#000 0%,#000 52%,transparent 100%);
  mask-image:linear-gradient(to bottom,#000 0%,#000 52%,transparent 100%);
}

header,footer,main,.site-footer,.site-header{
  position:relative;
  z-index:1;
}

#main-content{
  display:block;
  padding-top:var(--header-h);
}

/* --------------------------------------------------------------------------
   3. 排版
   -------------------------------------------------------------------------- */
h1,.h1{
  font-family:var(--font-head);
  font-weight:800;
  font-size:clamp(34px,5.4vw,56px);
  line-height:1.04;
  letter-spacing:-.01em;
  color:var(--paper);
}

h2,.h2{
  font-family:var(--font-head);
  font-weight:800;
  font-size:clamp(24px,3.2vw,32px);
  line-height:1.16;
  letter-spacing:-.005em;
  color:var(--paper);
}

h3,.h3{
  font-family:var(--font-head);
  font-weight:700;
  font-size:20px;
  line-height:1.35;
  letter-spacing:0;
  color:var(--paper);
}

h4,.h4{
  font-size:16px;
  font-weight:700;
  line-height:1.5;
}

p{
  max-width:38em;
}

strong,b{
  font-weight:700;
  color:#fff;
}

/* 等宽：只承担标注与定位 */
.mono,
.mono-label,
.eyebrow,
time,
.timeline-time{
  font-family:var(--font-mono);
  font-feature-settings:"tnum" 1;
}

.mono-label{
  display:inline-block;
  font-size:11.5px;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:var(--muted);
}

.eyebrow{
  display:inline-flex;
  align-items:center;
  gap:8px;
  font-size:11.5px;
  letter-spacing:.2em;
  text-transform:uppercase;
  color:var(--cyan);
}

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

/* 长文容器 */
.prose{
  max-width:38em;
  font-size:16.5px;
  line-height:1.8;
  color:var(--paper-soft);
}

.prose p + p{margin-top:1.05em;}
.prose h2{margin-top:2.2em;margin-bottom:.7em;}
.prose h3{margin-top:1.8em;margin-bottom:.5em;}
.prose ul,.prose ol{margin-top:1em;padding-left:1.2em;list-style:none;}
.prose li{position:relative;padding-left:1.1em;margin-bottom:.5em;}
.prose li::before{
  content:"";
  position:absolute;
  left:0;
  top:.72em;
  width:6px;
  height:1px;
  background:var(--cyan);
}
.prose a{
  color:var(--cyan);
  border-bottom:1px solid var(--cyan-line);
}
.prose a:hover{border-bottom-color:var(--cyan);}

/* --------------------------------------------------------------------------
   4. 容器与网格
   -------------------------------------------------------------------------- */
.shell{
  width:min(var(--shell),100% - (var(--gutter) * 2));
  margin-inline:auto;
}

.section-head{
  display:grid;
  gap:10px;
  padding-bottom:16px;
  border-bottom:1px solid var(--line-soft);
  margin-bottom:clamp(20px,3vw,34px);
}

.grid{
  display:grid;
  gap:clamp(16px,2.4vw,28px);
}

.grid--split{grid-template-columns:minmax(0,1fr) minmax(0,2.4fr);}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr));}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr));}
.grid--4{grid-template-columns:repeat(4,minmax(0,1fr));}

/* --------------------------------------------------------------------------
   5. 按钮与焦点
   -------------------------------------------------------------------------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:10px 18px;
  border:1px solid transparent;
  border-radius:var(--radius);
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.08em;
  line-height:1.2;
  white-space:nowrap;
  cursor:pointer;
  transition:background-color var(--dur) var(--ease),
             color var(--dur) var(--ease),
             border-color var(--dur) var(--ease),
             transform var(--dur) var(--ease);
}

.btn-primary{
  background:var(--cyan);
  border-color:var(--cyan);
  color:#04121A;
  font-weight:700;
}
.btn-primary:hover{background:#5BF0DC;border-color:#5BF0DC;}

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

.btn-orange{
  background:var(--orange);
  border-color:var(--orange);
  color:#150800;
  font-weight:700;
}
.btn-orange:hover{filter:brightness(1.08);}

.btn:active{transform:translateY(1px);}

a:focus-visible,
button:focus-visible,
[tabindex]:focus-visible,
summary:focus-visible{
  outline:2px solid var(--cyan);
  outline-offset:3px;
  border-radius:var(--radius);
}

/* --------------------------------------------------------------------------
   6. 头部
   -------------------------------------------------------------------------- */
.skip-link{
  position:fixed;
  top:-72px;
  left:16px;
  z-index:200;
  padding:10px 18px;
  background:var(--cyan);
  color:#04121A;
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.06em;
  border-radius:var(--radius);
  transition:top var(--dur) var(--ease);
}
.skip-link:focus{top:14px;}

.site-header{
  position:fixed;
  top:0;
  left:0;
  right:0;
  z-index:100;
  background:rgba(6,11,20,.30);
  -webkit-backdrop-filter:blur(14px) saturate(130%);
  backdrop-filter:blur(14px) saturate(130%);
  border-bottom:1px solid var(--line-soft);
  transition:background-color .24s var(--ease),
             border-color .24s var(--ease),
             box-shadow .24s var(--ease);
}

.site-header[data-condensed]{
  background:rgba(6,11,20,.96);
  border-bottom-color:var(--cyan-line);
  box-shadow:0 18px 40px -28px rgba(0,0,0,.95);
}

.header-shell{
  width:min(var(--shell),100% - (var(--gutter) * 2));
  margin-inline:auto;
  display:flex;
  align-items:center;
  gap:clamp(14px,2.6vw,44px);
  min-height:var(--header-h);
  transition:min-height .24s var(--ease);
}
.site-header[data-condensed] .header-shell{min-height:var(--header-h-condensed);}

/* 品牌 */
.brand-block{flex:0 0 auto;}

.brand-link{
  display:inline-flex;
  align-items:center;
  gap:12px;
}

.brand-mark{
  display:inline-block;
  padding:5px 7px;
  border:1px solid var(--cyan-line);
  background:var(--cyan-soft);
  color:var(--cyan);
  font-family:var(--font-mono);
  font-size:12.5px;
  font-weight:700;
  letter-spacing:.12em;
  line-height:1;
}

.brand-text{display:block;}

.brand-name{
  display:block;
  font-family:var(--font-head);
  font-weight:800;
  font-size:20px;
  line-height:1.08;
  letter-spacing:.02em;
  color:var(--paper);
}

.brand-line{
  display:block;
  margin-top:3px;
  font-family:var(--font-mono);
  font-size:10.5px;
  letter-spacing:.05em;
  color:var(--muted-dim);
  white-space:nowrap;
}

/* 移动按钮 */
.nav-toggle{display:none;}

/* 导航 */
.site-nav{
  display:flex;
  align-items:center;
  gap:clamp(12px,2vw,32px);
  margin-left:auto;
}

.nav-list{
  display:flex;
  align-items:center;
  gap:clamp(10px,1.7vw,26px);
}

.nav-item{
  display:flex;
  align-items:baseline;
  gap:5px;
}

.nav-index{
  font-family:var(--font-mono);
  font-size:9.5px;
  letter-spacing:.04em;
  color:var(--muted-dim);
  transform:translateY(-6px);
  transition:color var(--dur) var(--ease);
}

.nav-link{
  position:relative;
  display:inline-block;
  padding:6px 0;
  font-size:14.5px;
  letter-spacing:.02em;
  color:var(--paper);
  transition:color var(--dur) var(--ease);
}

.nav-link::after{
  content:"";
  position:absolute;
  left:0;
  right:0;
  bottom:0;
  height:1px;
  background:var(--cyan);
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform var(--dur) var(--ease);
}

.nav-link:hover,
.nav-link:focus-visible{color:var(--cyan);}
.nav-link:hover::after,
.nav-link:focus-visible::after{transform:scaleX(1);}

.nav-link[aria-current="page"]{color:var(--cyan);}
.nav-link[aria-current="page"]::after{transform:scaleX(1);}

.nav-item:has(.nav-link[aria-current="page"]) .nav-index{color:var(--cyan);}

.nav-actions{
  display:flex;
  align-items:center;
  gap:10px;
}

.nav-actions .btn{padding:8px 14px;}

/* 阅读进度 */
.header-progress{
  position:absolute;
  left:0;
  right:0;
  bottom:-1px;
  height:2px;
  display:block;
  pointer-events:none;
  background:transparent;
}

.header-progress-bar{
  display:block;
  width:0;
  height:100%;
  background:linear-gradient(90deg,var(--cyan) 0%,var(--cyan) 62%,var(--orange) 100%);
  transition:width .12s linear;
}

/* --------------------------------------------------------------------------
   7. 页脚
   -------------------------------------------------------------------------- */
.site-footer{
  margin-top:clamp(60px,9vw,132px);
  background:linear-gradient(180deg,var(--ink-800) 0%,var(--ink-900) 74%);
  border-top:1px solid var(--line);
  color:var(--paper);
}

.site-footer::before{
  content:"";
  position:absolute;
  top:-1px;
  left:0;
  width:min(180px,42vw);
  height:1px;
  background:var(--cyan);
}

.footer-shell{
  width:min(var(--shell),100% - (var(--gutter) * 2));
  margin-inline:auto;
  display:grid;
  grid-template-columns:minmax(210px,1fr) minmax(0,1.5fr) minmax(230px,.95fr);
  gap:clamp(28px,4vw,60px);
  padding:clamp(42px,6vw,72px) 0 clamp(26px,4vw,42px);
}

.footer-brand{display:grid;align-content:start;gap:10px;}

.footer-brand-link{
  display:inline-flex;
  align-items:center;
  gap:10px;
}

.footer-brand-name{
  font-family:var(--font-head);
  font-weight:800;
  font-size:22px;
  letter-spacing:.02em;
  line-height:1.1;
}

.footer-mono{
  font-family:var(--font-mono);
  font-size:10.5px;
  letter-spacing:.14em;
  color:var(--muted-dim);
  max-width:none;
}

.footer-tagline{
  font-size:15px;
  color:var(--paper-soft);
  max-width:20em;
}

.footer-note{
  font-size:12.5px;
  line-height:1.7;
  color:var(--muted-dim);
  max-width:24em;
}

.footer-cols{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:clamp(16px,2.4vw,28px);
}

.footer-col{display:grid;align-content:start;gap:12px;}

.footer-col-title{
  display:flex;
  align-items:baseline;
  gap:7px;
  padding-bottom:10px;
  border-bottom:1px solid var(--line-soft);
  font-family:var(--font-mono);
  font-size:11.5px;
  font-weight:500;
  letter-spacing:.16em;
  color:var(--muted);
}

.footer-col-index{
  font-size:9.5px;
  color:var(--cyan);
  opacity:.8;
}

.footer-list{display:grid;gap:2px;}

.footer-link{
  display:inline-block;
  padding:4px 0;
  font-size:14.5px;
  color:var(--paper-soft);
  transition:color var(--dur) var(--ease),transform var(--dur) var(--ease);
}
.footer-link:hover,
.footer-link:focus-visible{
  color:var(--cyan);
  transform:translateX(3px);
}

.footer-contact{display:grid;align-content:start;gap:12px;}

.contact-list{display:grid;gap:12px;}

.contact-item{
  display:grid;
  gap:2px;
  padding-bottom:10px;
  border-bottom:1px dashed var(--line-faint);
}

.contact-key{
  font-family:var(--font-mono);
  font-size:10.5px;
  letter-spacing:.16em;
  color:var(--muted-dim);
}

.contact-value{
  font-family:var(--font-mono);
  font-size:12.5px;
  line-height:1.6;
  letter-spacing:.01em;
  color:var(--paper);
  word-break:break-word;
}

.footer-base{
  width:min(var(--shell),100% - (var(--gutter) * 2));
  margin-inline:auto;
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:10px 24px;
  padding:16px 0 26px;
  border-top:1px solid var(--line-soft);
}

.footer-copy,
.footer-icp{
  max-width:none;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.06em;
  color:var(--muted-dim);
}

/* --------------------------------------------------------------------------
   8. 通用组件
   -------------------------------------------------------------------------- */

/* 面板与卡片 */
.panel{
  background:var(--ink-800);
  border:1px solid var(--line-soft);
  border-radius:var(--radius);
  padding:clamp(18px,3vw,32px);
}

.panel--solid{
  background:var(--ink-700);
  border-color:var(--line);
}

.panel--glass{
  background:var(--glass);
  border-color:var(--glass-line);
  -webkit-backdrop-filter:blur(12px);
  backdrop-filter:blur(12px);
}

.card{
  display:block;
  background:var(--ink-700);
  border:1px solid var(--line-soft);
  border-radius:var(--radius);
  padding:clamp(16px,2.4vw,22px);
  transition:border-color var(--dur) var(--ease),
             background-color var(--dur) var(--ease),
             transform var(--dur) var(--ease);
}

a.card:hover,
a.card:focus-visible{
  border-color:var(--cyan-line);
  background:var(--ink-800);
  transform:translateY(-2px);
}

/* 标签与状态 */
.badge{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:3px 8px;
  border:1px solid var(--line);
  border-radius:var(--radius);
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.08em;
  line-height:1.3;
  color:var(--muted);
  background:rgba(17,31,51,.85);
}

.badge--cyan{color:var(--cyan);border-color:var(--cyan-line);background:var(--cyan-soft);}
.badge--orange{color:var(--orange);border-color:rgba(255,122,47,.45);background:var(--orange-soft);}
.badge--green{color:var(--green);border-color:rgba(61,214,140,.45);background:rgba(61,214,140,.12);}
.badge--muted{color:var(--muted-dim);background:rgba(17,31,51,.85);}

/* 面包屑 */
.breadcrumbs{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.08em;
  color:var(--muted-dim);
  padding:0;
  margin:0;
  list-style:none;
}

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

.breadcrumbs a{
  color:var(--muted);
  transition:color var(--dur) var(--ease);
}
.breadcrumbs a:hover,
.breadcrumbs a:focus-visible{color:var(--cyan);}

.breadcrumbs [aria-current="page"]{color:var(--paper);}

.breadcrumb-sep{
  color:var(--line);
  font-size:10px;
}

/* 时间轴 */
.timeline{
  position:relative;
  padding-left:28px;
}

.timeline::before{
  content:"";
  position:absolute;
  left:5px;
  top:8px;
  bottom:8px;
  width:1px;
  background:linear-gradient(180deg,var(--cyan) 0%,var(--line) 88%);
}

.timeline-item{
  position:relative;
  padding:14px 0 22px;
}

.timeline-node{
  position:absolute;
  left:-28px;
  top:20px;
  width:11px;
  height:11px;
  border:1px solid var(--cyan);
  background:var(--ink-900);
  transform:rotate(45deg);
  transition:background-color var(--dur) var(--ease);
}

.timeline-item[data-state="past"] .timeline-node{background:var(--cyan);}
.timeline-item[data-state="now"] .timeline-node{background:var(--orange);border-color:var(--orange);}

.timeline-time{
  display:inline-block;
  font-size:12px;
  letter-spacing:.08em;
  color:var(--cyan);
  margin-bottom:6px;
}

/* 可展开内容组 */
.disclosure{
  border:1px solid var(--line-soft);
  border-radius:var(--radius);
  background:var(--ink-700);
  transition:border-color var(--dur) var(--ease),box-shadow var(--dur) var(--ease);
}

.disclosure + .disclosure{margin-top:10px;}

.disclosure[data-open]{
  border-color:var(--cyan-line);
  box-shadow:inset 2px 0 0 0 var(--cyan);
}

.disclosure-trigger{
  display:flex;
  align-items:center;
  gap:14px;
  width:100%;
  padding:15px 18px;
  text-align:left;
  cursor:pointer;
  font-size:16px;
  line-height:1.5;
  color:var(--paper);
  transition:color var(--dur) var(--ease),background-color var(--dur) var(--ease);
}

.disclosure-trigger:hover{background:rgba(23,224,200,.06);}
.disclosure[data-open] .disclosure-trigger{color:var(--cyan);}

.disclosure-index{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.06em;
  color:var(--muted-dim);
  flex:0 0 auto;
}

.disclosure-label{flex:1 1 auto;}

.disclosure-icon{
  position:relative;
  flex:0 0 auto;
  width:12px;
  height:12px;
  color:currentColor;
}

.disclosure-icon::before,
.disclosure-icon::after{
  content:"";
  position:absolute;
  background:currentColor;
}

.disclosure-icon::before{
  left:0;
  right:0;
  top:50%;
  height:1.5px;
  transform:translateY(-50%);
}

.disclosure-icon::after{
  top:0;
  bottom:0;
  left:50%;
  width:1.5px;
  transform:translateX(-50%);
  transition:transform var(--dur) var(--ease);
}

.disclosure[data-open] .disclosure-icon::after{
  transform:translateX(-50%) scaleY(0);
}

.disclosure-panel{
  padding:0 18px 18px;
  font-size:15px;
  line-height:1.78;
  color:var(--paper-soft);
}

.disclosure-panel > * + *{margin-top:.8em;}

/* 仅当 JS 接管后才收敛折叠状态，无脚本时内容仍完整可见 */
.disclosure[data-ready]:not([data-open]) .disclosure-panel{display:none;}

/* 图片容器 */
.media-frame{
  position:relative;
  display:block;
  overflow:hidden;
  width:100%;
  aspect-ratio:16 / 9;
  background:var(--ink-700);
  border:1px solid var(--line-soft);
  border-radius:var(--radius);
}

.media-frame::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background-image:
    linear-gradient(rgba(23,224,200,.10) 1px,transparent 1px),
    linear-gradient(90deg,rgba(23,224,200,.10) 1px,transparent 1px);
  background-size:36px 36px;
}

.media-frame > img,
.media-frame > picture > img{
  width:100%;
  height:100%;
  object-fit:cover;
  position:relative;
  z-index:1;
}

.media-frame--wide{aspect-ratio:21 / 9;}
.media-frame--square{aspect-ratio:1 / 1;}
.media-frame--tall{aspect-ratio:4 / 5;}

.media-caption{
  margin-top:8px;
  font-family:var(--font-mono);
  font-size:11.5px;
  letter-spacing:.06em;
  color:var(--muted-dim);
}

/* --------------------------------------------------------------------------
   9. 响应式
   -------------------------------------------------------------------------- */
@media (max-width:1180px){
  .brand-line{display:none;}
  .nav-item .nav-index{display:none;}
}

@media (max-width:960px){
  :root{--header-h:68px;}

  .nav-toggle{
    display:inline-flex;
    align-items:center;
    gap:10px;
    margin-left:auto;
    padding:9px 12px;
    border:1px solid var(--line);
    border-radius:var(--radius);
    background:rgba(17,31,51,.9);
    color:var(--paper);
    font-family:var(--font-mono);
    font-size:11.5px;
    letter-spacing:.16em;
    cursor:pointer;
    transition:border-color var(--dur) var(--ease),color var(--dur) var(--ease);
  }

  .nav-toggle[aria-expanded="true"]{
    border-color:var(--cyan);
    color:var(--cyan);
  }

  .nav-toggle-bars{
    display:flex;
    flex-direction:column;
    justify-content:center;
    gap:3px;
    width:16px;
    height:12px;
  }

  .nav-toggle-bars i{
    display:block;
    height:1.5px;
    background:currentColor;
    transition:transform .18s var(--ease),opacity .18s var(--ease);
  }

  .nav-toggle[aria-expanded="true"] .nav-toggle-bars i:nth-child(1){
    transform:translateY(4.5px) rotate(45deg);
  }
  .nav-toggle[aria-expanded="true"] .nav-toggle-bars i:nth-child(2){
    opacity:0;
  }
  .nav-toggle[aria-expanded="true"] .nav-toggle-bars i:nth-child(3){
    transform:translateY(-4.5px) rotate(-45deg);
  }

  .site-nav{
    display:none;
    position:absolute;
    top:100%;
    left:0;
    right:0;
    margin-left:0;
    flex-direction:column;
    align-items:stretch;
    gap:0;
    padding:6px var(--gutter) 22px;
    background:rgba(8,14,24,.99);
    border-bottom:1px solid var(--line);
    box-shadow:0 34px 64px -34px rgba(0,0,0,.95);
    max-height:calc(100vh - var(--header-h));
    overflow-y:auto;
    -webkit-overflow-scrolling:touch;
  }

  .site-nav[data-open]{display:flex;}

  .nav-list{
    flex-direction:column;
    align-items:stretch;
    gap:0;
  }

  .nav-item{
    align-items:center;
    gap:14px;
    padding:2px 0;
    border-bottom:1px solid var(--line-faint);
  }

  .nav-index{
    display:inline-block;
    transform:none;
    width:20px;
    font-size:10px;
    color:var(--muted-dim);
  }

  .nav-link{
    flex:1 1 auto;
    display:block;
    padding:13px 0;
    font-size:16px;
  }

  .nav-link::after{display:none;}

  .nav-link[aria-current="page"]{
    color:var(--cyan);
    box-shadow:inset 2px 0 0 0 var(--cyan);
    padding-left:10px;
  }

  .nav-actions{
    flex-direction:column;
    align-items:stretch;
    gap:10px;
    padding-top:18px;
  }

  .nav-actions .btn{
    width:100%;
    padding:13px 18px;
    font-size:13px;
  }

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

  .grid--2{grid-template-columns:1fr;}

  .footer-shell{
    grid-template-columns:repeat(2,minmax(0,1fr));
  }

  .footer-brand{grid-column:1 / -1;}
}

@media (max-width:720px){
  body::before{opacity:.3;}

  h1,.h1{font-size:clamp(30px,8vw,40px);}
  h2,.h2{font-size:clamp(22px,6vw,28px);}
  .prose{font-size:16px;}

  .footer-cols{grid-template-columns:repeat(2,minmax(0,1fr));}
  .footer-base{flex-direction:column;align-items:flex-start;gap:6px;}
}

@media (max-width:560px){
  .footer-shell{grid-template-columns:1fr;}
  .footer-cols{grid-template-columns:1fr;gap:22px;}
  .brand-name{font-size:18px;}
  .nav-toggle-label{display:none;}
  .nav-toggle{padding:10px;}
  .disclosure-trigger{font-size:15px;padding:14px 14px;}
  .disclosure-panel{padding:0 14px 16px;}
}

/* --------------------------------------------------------------------------
   10. 降低动效
   -------------------------------------------------------------------------- */
@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;
  }

  .header-progress-bar{transition:none;}
  .footer-link:hover{transform:none;}
  a.card:hover{transform:none;}
  .btn:active{transform:none;}
}