/* ==========================================================================
   老虎游戏机站 · 共享样式 /assets/site.css
   深井黑机箱 + 蓝图网格 + 霓虹橙灯管 + 电光蓝电流
   ========================================================================== */

/* ---------- 1. 变量 ---------- */
:root{
  --ink:#0B0C10;
  --surface:#14161C;
  --line:#23262F;
  --line-soft:rgba(35,38,47,.62);
  --orange:#FF6A1A;
  --orange-soft:#FFB36B;
  --blue:#2ED3FF;
  --green:#9BFF4D;
  --paper:#F2EDE4;
  --paper-soft:rgba(242,237,228,.82);
  --paper-dim:rgba(242,237,228,.62);
  --muted:#8A8F98;
  --moss:#7FA37A;
  --clay:#C2603F;

  --shell:1280px;
  --gutter:clamp(18px,4vw,40px);
  --cut:14px;
  --r-cap:999px;
  --ease:cubic-bezier(.22,1,.36,1);

  --font-display:"HarmonyOS Sans SC","Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-body:"PingFang SC","HarmonyOS Sans SC",system-ui,-apple-system,"Segoe UI","Microsoft YaHei",sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,"Courier New",monospace;
}

/* ---------- 2. Reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
  scroll-padding-top:120px;
}
body,h1,h2,h3,h4,h5,p,ul,ol,li,figure,blockquote,dl,dd,fieldset{margin:0;padding:0}
ul,ol{list-style:none}
img,svg,video,canvas{display:block;max-width:100%}
img{height:auto}
a{color:inherit;text-decoration:none}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--blue);outline-offset:3px;border-radius:3px}
::selection{background:var(--orange);color:#140A03}

/* ---------- 3. 页面底纹与中文排版 ---------- */
body{
  min-height:100vh;
  font-family:var(--font-body);
  font-size:16.5px;
  line-height:1.75;
  font-weight:400;
  letter-spacing:.01em;
  color:var(--paper);
  background-color:var(--ink);
  background-image:
    linear-gradient(rgba(35,38,47,.48) 1px,transparent 1px),
    linear-gradient(90deg,rgba(35,38,47,.48) 1px,transparent 1px);
  background-size:48px 48px;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
::-webkit-scrollbar{width:10px;height:10px}
::-webkit-scrollbar-track{background:var(--line)}
::-webkit-scrollbar-thumb{background:#3B3F4B;border:2px solid var(--line);border-radius:10px}
::-webkit-scrollbar-thumb:hover{background:var(--orange)}
* {scrollbar-color:#3B3F4B var(--line); scrollbar-width:thin}

h1,h2,h3,h4{font-family:var(--font-display);font-weight:900;line-height:1.18;letter-spacing:.005em;text-shadow:0 0 1px var(--ink),0 0 18px rgba(255,106,26,.18)}
h1{font-size:clamp(40px,7vw,84px)}
h2{font-size:clamp(26px,3.4vw,36px)}
h3{font-size:clamp(19px,2vw,22px)}
strong{font-weight:700}
p{color:var(--paper-soft)}

/* ---------- 4. 通用工具 ---------- */
.shell{width:100%;max-width:var(--shell);margin-inline:auto;padding-inline:var(--gutter)}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums;letter-spacing:.02em}
.coord{font-family:var(--font-mono);font-size:11.5px;letter-spacing:.16em;color:var(--muted);text-transform:uppercase}
.lede{font-size:clamp(17px,2vw,20px);line-height:1.7;color:var(--paper);max-width:62ch}
.note{font-size:13px;color:var(--muted);font-family:var(--font-mono);letter-spacing:.04em}

.skip-link{
  position:fixed;top:10px;left:10px;z-index:220;
  padding:10px 18px;border-radius:var(--r-cap);
  background:var(--orange);color:#140A03;
  font-family:var(--font-mono);font-size:13px;font-weight:700;
  transform:translateY(-180%);
  transition:transform .2s var(--ease);
}
.skip-link:focus,.skip-link:focus-visible{transform:translateY(0)}

.scroll-progress{
  position:fixed;top:0;left:0;right:0;height:2px;z-index:200;
  transform:scaleX(0);transform-origin:0 50%;
  background:linear-gradient(90deg,var(--orange),var(--orange-soft) 60%,var(--blue));
  box-shadow:0 0 12px rgba(255,106,26,.75);
  pointer-events:none;
}
.copy-proxy{position:fixed;top:-1000px;left:-1000px;opacity:0}

/* ---------- 5. 页头：悬浮胶囊浮岛 ---------- */
.site-header{
  position:fixed;top:0;left:0;right:0;z-index:120;
  padding:16px var(--gutter);
  pointer-events:none;
  transition:padding .3s var(--ease);
}
.header__inner{
  position:relative;
  max-width:var(--shell);margin-inline:auto;
  display:flex;align-items:center;gap:10px;
  pointer-events:none;
}
.header__inner > *{pointer-events:auto}

.brand{
  display:inline-flex;align-items:center;gap:10px;
  padding:8px 16px 8px 13px;
  border:1px solid var(--line);border-radius:var(--r-cap);
  background:rgba(20,22,28,.88);
  -webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);
  box-shadow:0 10px 26px rgba(0,0,0,.42);
  transition:border-color .18s var(--ease),transform .18s var(--ease);
}
.brand:hover{border-color:var(--orange);transform:translateY(-2px)}
.brand__mark{display:inline-flex;align-items:flex-end;gap:3px;height:18px;flex:0 0 auto}
.brand__mark i{display:block;width:4px;border-radius:1px;transform:skewX(-10deg)}
.brand__mark i:nth-child(1){height:10px;background:var(--blue)}
.brand__mark i:nth-child(2){height:18px;background:var(--orange);box-shadow:0 0 10px rgba(255,106,26,.75)}
.brand__mark i:nth-child(3){height:13px;background:var(--green)}
.brand__text{display:flex;flex-direction:column;gap:1px;line-height:1.15}
.brand__name{
  font-family:var(--font-display);font-weight:900;font-size:15px;letter-spacing:.05em;
  color:var(--paper);text-shadow:0 0 1px var(--ink),0 0 12px rgba(255,106,26,.4);
  white-space:nowrap;
}
.brand__tag{
  font-family:var(--font-mono);font-size:10px;letter-spacing:.14em;
  color:var(--muted);white-space:nowrap;
}

.size-badge{
  display:inline-flex;align-items:baseline;gap:1px;
  padding:7px 12px;flex:0 0 auto;
  border:1px dashed var(--line);border-radius:var(--r-cap);
  background:rgba(11,12,16,.62);
  font-family:var(--font-mono);font-size:11.5px;font-weight:700;letter-spacing:.06em;
  color:var(--blue);
  transition:border-color .18s var(--ease),color .18s var(--ease);
}
.size-badge__num{font-size:13px;color:var(--orange)}
.size-badge:hover{border-color:var(--blue);color:var(--orange-soft)}

.nav{margin-left:auto}
.nav__list{
  display:flex;align-items:center;gap:2px;padding:5px;
  border:1px solid var(--line);border-radius:var(--r-cap);
  background:rgba(20,22,28,.84);
  -webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);
  box-shadow:0 12px 30px rgba(0,0,0,.45);
  transition:padding .3s var(--ease);
}
.nav__link{
  display:inline-flex;align-items:center;gap:6px;
  padding:8px 14px;border-radius:var(--r-cap);
  font-size:14px;font-weight:600;color:var(--paper);white-space:nowrap;
  transition:color .18s var(--ease),background-color .18s var(--ease),padding .3s var(--ease),font-size .3s var(--ease);
}
.nav__idx{font-family:var(--font-mono);font-size:10px;letter-spacing:.08em;color:var(--muted);transition:color .18s var(--ease)}
.nav__link:hover{color:var(--blue);background:rgba(46,211,255,.09)}
.nav__link:hover .nav__idx{color:var(--blue)}
.nav__link[aria-current="page"]{
  color:#fff;
  background:linear-gradient(180deg,rgba(255,106,26,.26),rgba(255,106,26,.07));
  box-shadow:inset 0 0 0 1px rgba(255,106,26,.6);
}
.nav__link[aria-current="page"] .nav__idx{color:var(--orange)}

.header__actions{display:flex;align-items:center;gap:8px;flex:0 0 auto}

.site-header[data-scrolled]{padding-top:8px;padding-bottom:8px}
.site-header[data-scrolled] .nav__list{padding:3px}
.site-header[data-scrolled] .nav__link{padding:6px 12px;font-size:13px}
.site-header[data-scrolled] .brand{padding:6px 13px 6px 11px}
.site-header[data-scrolled] .brand__tag{display:none}

/* ---------- 6. 通用按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:10px 18px;
  border:1px solid transparent;border-radius:var(--r-cap);
  font-family:var(--font-display);font-size:14px;font-weight:800;letter-spacing:.03em;
  white-space:nowrap;
  transition:background-color .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease),transform .18s var(--ease),box-shadow .18s var(--ease);
}
.btn--primary{
  background:var(--orange);color:#140A03;
  box-shadow:inset 0 0 0 1px rgba(255,179,107,.55),0 8px 22px rgba(255,106,26,.26);
}
.btn--primary:hover{background:var(--orange-soft);transform:translateY(-2px);box-shadow:inset 0 0 0 1px rgba(255,179,107,.8),0 12px 28px rgba(255,106,26,.36)}
.btn--ghost{
  background:rgba(20,22,28,.72);border-color:var(--line);color:var(--paper);
}
.btn--ghost:hover{border-color:var(--blue);color:var(--blue);transform:translateY(-2px)}
.btn--sm{padding:7px 13px;font-size:13px}

/* ---------- 7. 移动导航开关 ---------- */
.nav-toggle{
  display:none;
  position:relative;flex:0 0 auto;
  width:44px;height:44px;
  align-items:center;justify-content:center;
  border:1px solid var(--line);border-radius:var(--r-cap);
  background:rgba(20,22,28,.92);
  transition:border-color .18s var(--ease);
}
.nav-toggle:hover{border-color:var(--orange)}
.nav-toggle__bars{display:flex;flex-direction:column;justify-content:space-between;width:18px;height:14px}
.nav-toggle__bars i{
  display:block;height:2px;width:100%;border-radius:2px;background:var(--paper);
  transition:transform .22s var(--ease),opacity .18s var(--ease),background-color .18s var(--ease);
}
.site-header[data-open] .nav-toggle{border-color:var(--orange)}
.site-header[data-open] .nav-toggle__bars i{background:var(--orange)}
.site-header[data-open] .nav-toggle__bars i:nth-child(1){transform:translateY(6px) rotate(45deg)}
.site-header[data-open] .nav-toggle__bars i:nth-child(2){opacity:0}
.site-header[data-open] .nav-toggle__bars i:nth-child(3){transform:translateY(-6px) rotate(-45deg)}

/* ---------- 8. 页脚：编辑部目录 ---------- */
.site-footer{
  position:relative;margin-top:clamp(72px,10vw,140px);
  border-top:1px solid var(--line);
  background:linear-gradient(180deg,rgba(20,22,28,0),rgba(20,22,28,.92) 45%,#0B0C10);
}
.site-footer::before{
  content:"";position:absolute;top:-1px;left:0;
  width:min(320px,42%);height:1px;
  background:linear-gradient(90deg,var(--orange),rgba(255,106,26,0));
  box-shadow:0 0 14px rgba(255,106,26,.8);
}
.footer__top{
  display:grid;grid-template-columns:minmax(230px,1.05fr) minmax(0,2fr);
  gap:clamp(26px,5vw,64px);
  padding:clamp(40px,6vw,76px) 0 clamp(26px,4vw,44px);
}
.footer__brand{display:flex;flex-direction:column;align-items:flex-start;gap:16px}
.brand--stack{flex-direction:row;align-items:center;background:transparent;border-color:transparent;box-shadow:none;padding:0}
.brand--stack:hover{transform:none;border-color:transparent}
.brand--stack:hover .brand__name{color:var(--orange-soft)}
.footer__note{font-size:14.5px;line-height:1.8;color:var(--paper-dim);max-width:34ch}
.footer__coord{font-family:var(--font-mono);font-size:11px;letter-spacing:.16em;color:var(--muted);text-transform:uppercase}

.footer__index{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:clamp(16px,3vw,32px)}
.footer__title{
  display:flex;align-items:baseline;gap:8px;
  margin-bottom:14px;
  font-family:var(--font-mono);font-size:11.5px;font-weight:700;
  letter-spacing:.18em;color:var(--muted);text-transform:uppercase;
  text-shadow:none;
}
.footer__num{color:var(--orange)}
.footer__list{display:flex;flex-direction:column;gap:2px}
.footer__link{
  position:relative;display:inline-block;
  padding:5px 0;font-size:14.5px;color:var(--paper);opacity:.86;
  transition:color .18s var(--ease),opacity .18s var(--ease);
}
.footer__link::after{
  content:"";position:absolute;left:0;bottom:1px;width:100%;height:1px;
  background:var(--blue);transform:scaleX(0);transform-origin:0 50%;
  transition:transform .18s var(--ease);
}
.footer__link:hover{color:var(--blue);opacity:1}
.footer__link:hover::after{transform:scaleX(1)}

.footer__bar{
  display:flex;flex-wrap:wrap;align-items:baseline;gap:10px 28px;
  padding:22px 0 40px;
  border-top:1px solid var(--line);
  font-size:12.5px;color:var(--muted);line-height:1.9;
}
.footer__contact{font-family:var(--font-mono);letter-spacing:.02em;color:var(--paper-dim);flex:1 1 420px}
.footer__legal{display:flex;align-items:center;gap:10px;font-family:var(--font-mono);color:var(--muted)}
.footer__copy{color:var(--paper-dim)}
.footer__icp{color:var(--muted)}
.footer__dot{width:4px;height:4px;border-radius:50%;background:var(--orange);box-shadow:0 0 8px rgba(255,106,26,.9)}
.footer__hint{flex:1 1 100%;font-size:12px;color:var(--muted)}

.to-top{
  position:fixed;right:22px;bottom:22px;z-index:110;
  width:46px;height:46px;border-radius:50%;
  display:inline-flex;align-items:center;justify-content:center;
  border:1px solid var(--line);
  background:rgba(20,22,28,.9);
  -webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);
  color:var(--paper);
  opacity:0;visibility:hidden;transform:translateY(10px);
  transition:opacity .2s var(--ease),transform .2s var(--ease),border-color .18s var(--ease),color .18s var(--ease),visibility .2s;
}
.to-top[data-visible]{opacity:1;visibility:visible;transform:translateY(0)}
.to-top:hover{border-color:var(--orange);color:var(--orange);box-shadow:0 0 18px rgba(255,106,26,.35)}

/* ---------- 9. 面包屑 / 章节 / 正文 ---------- */
.crumb{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:11.5px;letter-spacing:.1em;
  color:var(--muted);text-transform:uppercase;
}
.crumb a{color:var(--muted);transition:color .18s var(--ease)}
.crumb a:hover{color:var(--blue)}
.crumb__sep{color:var(--line);font-style:normal}

.section{position:relative;padding:clamp(48px,7vw,96px) 0}
.section__head{
  display:grid;grid-template-columns:auto minmax(0,1fr);
  gap:clamp(14px,3vw,32px);align-items:start;
  margin-bottom:clamp(22px,3.5vw,44px);
}
.section__num{
  font-family:var(--font-mono);font-weight:800;
  font-size:clamp(64px,11vw,132px);line-height:.78;letter-spacing:-.05em;
  color:var(--line);
  text-shadow:none;
  transition:color .5s var(--ease),text-shadow .5s var(--ease);
}
.section__num.is-lit{color:var(--orange);text-shadow:0 0 26px rgba(255,106,26,.4)}
.section__title{font-family:var(--font-display);font-weight:900;font-size:clamp(23px,3vw,34px);line-height:1.2;margin-bottom:8px}
.section__kicker{
  font-family:var(--font-mono);font-size:11.5px;letter-spacing:.2em;
  color:var(--muted);text-transform:uppercase;margin-bottom:10px;
}
.section__body{max-width:68ch}
.prose{max-width:68ch}
.prose p{margin-bottom:1.05em;color:var(--paper-soft)}
.prose p:last-child{margin-bottom:0}
.prose a{color:var(--blue);border-bottom:1px solid rgba(46,211,255,.35);transition:border-color .18s var(--ease)}
.prose a:hover{border-bottom-color:var(--blue)}

.glow-rule{
  position:relative;height:1px;border:0;margin:0;
  background:var(--line);overflow:visible;
}
.glow-rule::after{
  content:"";position:absolute;left:0;top:0;height:1px;
  width:min(220px,34%);
  background:linear-gradient(90deg,var(--orange),rgba(255,106,26,0));
  box-shadow:0 0 12px rgba(255,106,26,.7);
}

/* ---------- 10. 网格 / 卡片 / 面板 ---------- */
.grid-2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:clamp(16px,2.4vw,28px)}
.grid-3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:clamp(16px,2.4vw,28px)}

.card{
  position:relative;
  border:1px solid var(--line);
  background:linear-gradient(180deg,#14161C,#101218);
  transition:border-color .12s var(--ease),transform .12s var(--ease),box-shadow .12s var(--ease);
}
.card:hover{border-color:var(--orange);transform:translateY(-2px);box-shadow:0 16px 36px rgba(0,0,0,.55)}
.card--cut{
  --cut:14px;
  clip-path:polygon(var(--cut) 0,100% 0,100% calc(100% - var(--cut)),calc(100% - var(--cut)) 100%,0 100%,0 var(--cut));
}
.card--cut::before{
  content:"";position:absolute;top:0;left:0;height:1px;
  width:calc(100% - var(--cut));
  background:linear-gradient(90deg,rgba(255,106,26,0),var(--orange-soft));
  pointer-events:none;
}
.card__body{padding:clamp(18px,2vw,24px)}
.card__meta{
  display:flex;flex-wrap:wrap;gap:8px 14px;align-items:center;
  font-family:var(--font-mono);font-size:11.5px;letter-spacing:.08em;color:var(--muted);
}

.panel{
  position:relative;
  border:1px solid var(--line);background:var(--surface);
  padding:clamp(18px,2.2vw,28px);
}

/* ---------- 11. 标签 / 筛选 ---------- */
.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:3px 10px;border:1px solid var(--line);border-radius:var(--r-cap);
  font-family:var(--font-mono);font-size:11.5px;letter-spacing:.06em;
  color:var(--muted);background:rgba(11,12,16,.55);
}
.tag--blue{border-color:rgba(46,211,255,.45);color:var(--blue)}
.tag--green{border-color:rgba(155,255,77,.4);color:var(--green)}
.tag--clay{border-color:rgba(194,96,63,.55);color:var(--clay)}

.chip-row{display:flex;flex-wrap:wrap;gap:8px}
.chip{
  display:inline-flex;align-items:center;gap:6px;
  padding:7px 14px;border:1px solid var(--line);border-radius:var(--r-cap);
  font-family:var(--font-mono);font-size:12.5px;letter-spacing:.05em;
  color:var(--muted);background:rgba(20,22,28,.7);
  transition:border-color .18s var(--ease),color .18s var(--ease),background-color .18s var(--ease);
}
.chip:hover{border-color:var(--blue);color:var(--blue)}
.chip[aria-pressed="true"]{
  border-color:var(--blue);color:var(--ink);background:var(--blue);
  box-shadow:0 0 16px rgba(46,211,255,.35);
}

/* ---------- 12. 折叠面板 ---------- */
.collapse{
  border:1px solid var(--line);background:var(--surface);
  transition:border-color .18s var(--ease);
}
.collapse + .collapse{margin-top:-1px}
.collapse[data-open]{border-color:rgba(255,106,26,.55)}
.collapse__head{
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  width:100%;padding:15px 18px;text-align:left;
  font-family:var(--font-display);font-weight:800;font-size:15.5px;color:var(--paper);
}
.collapse__head::after{
  content:"+";flex:0 0 auto;
  font-family:var(--font-mono);font-size:16px;color:var(--orange);
  transition:transform .2s var(--ease);
}
.collapse__head[aria-expanded="true"]{color:var(--orange-soft)}
.collapse__head[aria-expanded="true"]::after{content:"–"}
.collapse__body{padding:0 18px 18px;max-width:68ch}
.collapse__body p{font-size:15.5px;color:var(--paper-soft)}

/* ---------- 13. 复制按钮 ---------- */
[data-copy]{
  display:inline-flex;align-items:center;gap:8px;
  padding:8px 14px;border:1px solid var(--line);border-radius:var(--r-cap);
  font-family:var(--font-mono);font-size:13px;letter-spacing:.06em;
  color:var(--paper);background:rgba(15,17,22,.85);
  transition:border-color .18s var(--ease),color .18s var(--ease),background-color .25s var(--ease);
}
[data-copy]:hover{border-color:var(--blue);color:var(--blue)}
[data-copy].is-copied{
  border-color:var(--green);color:var(--ink);background:var(--green);
  box-shadow:0 0 20px rgba(155,255,77,.45);
}

/* ---------- 14. 媒体容器（供页面阶段放图） ---------- */
.media-frame{
  position:relative;overflow:hidden;
  border:1px solid var(--line);
  background-color:var(--surface);
  background-image:
    linear-gradient(135deg,rgba(255,106,26,.12),transparent 46%),
    linear-gradient(315deg,rgba(46,211,255,.12),transparent 46%);
}
.media-frame::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background-image:
    linear-gradient(rgba(35,38,47,.85) 1px,transparent 1px),
    linear-gradient(90deg,rgba(35,38,47,.85) 1px,transparent 1px);
  background-size:24px 24px;
  opacity:.55;
}
.media-frame img{width:100%;height:100%;object-fit:cover;position:relative;z-index:1}
.media-frame--16x9{aspect-ratio:16/9}
.media-frame--4x3{aspect-ratio:4/3}
.media-frame--1x1{aspect-ratio:1/1}
.media-frame--3x4{aspect-ratio:3/4}

/* ---------- 15. 响应式 ---------- */
@media (max-width:1180px){
  .header__actions .btn--ghost{display:none}
  .brand__tag{display:none}
  .nav__link{padding:8px 12px;font-size:13.5px}
}
@media (max-width:1040px){
  .nav__idx{display:none}
  .footer__top{grid-template-columns:1fr}
  .footer__brand{gap:12px}
}
@media (max-width:900px){
  .grid-3{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (max-width:860px){
  body{padding-bottom:82px;background-size:32px 32px}
  .site-header{
    top:auto;bottom:0;
    padding:8px 12px calc(8px + env(safe-area-inset-bottom));
    background:linear-gradient(180deg,rgba(11,12,16,.35),rgba(11,12,16,.97) 42%);
    border-top:1px solid var(--line);
    -webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);
    pointer-events:auto;
    transition:padding .3s var(--ease);
  }
  .header__inner{gap:8px;flex-wrap:nowrap}
  .brand{padding:7px 12px 7px 10px}
  .brand__name{font-size:14px}
  .size-badge{margin-left:auto}
  .header__actions{display:none}
  .nav-toggle{display:inline-flex}
  .nav{
    position:absolute;left:12px;right:12px;bottom:calc(100% + 10px);
    margin-left:0;
    visibility:hidden;opacity:0;transform:translateY(10px);
    transition:opacity .22s var(--ease),transform .28s var(--ease),visibility .22s;
  }
  .site-header[data-open] .nav{visibility:visible;opacity:1;transform:translateY(0)}
  .nav__list{
    flex-wrap:nowrap;overflow-x:auto;overflow-y:hidden;
    scroll-snap-type:x mandatory;
    gap:4px;padding:6px;border-radius:18px;
    box-shadow:0 -12px 34px rgba(0,0,0,.6);
    -webkit-overflow-scrolling:touch;
  }
  .nav__item{scroll-snap-align:start;flex:0 0 auto}
  .nav__link{padding:9px 14px;font-size:14px}
  .nav__idx{display:none}
  .footer__index{grid-template-columns:repeat(2,minmax(0,1fr));gap:22px}
  .footer__bar{padding-bottom:26px}
  .to-top{right:14px;bottom:96px;width:42px;height:42px}
  .section__head{grid-template-columns:1fr;gap:8px}
  .section__num{font-size:clamp(56px,18vw,96px);line-height:.85}
}
@media (max-width:560px){
  .grid-2,.grid-3{grid-template-columns:1fr}
  .footer__contact{flex:1 1 100%}
  .footer__hint{font-size:11.5px}
}

/* ---------- 16. 动效偏好 ---------- */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms!important;
    animation-iteration-count:1!important;
    transition-duration:.001ms!important;
    scroll-behavior:auto!important;
  }
  .card:hover,.brand:hover,.btn:hover{transform:none}
  .footer__link:hover::after{transform:scaleX(1)}
}