/* ==========================================================================
   365看台 · /assets/site.css
   夜间球场看台 + 数据仪表盘 · 共享外壳与通用组件
   ========================================================================== */

/* ---------- 1. 变量 ---------- */
:root{
  --ink-night:#08131F;
  --pitch-navy:#12293D;
  --fluo-cyan:#3DF0CF;
  --stand-orange:#FF7A2F;
  --mountain-mist:#8C9BA8;
  --indigo-deep:#3B2E7E;
  --wine-deep:#6E1F2E;
  --sand-paper:#F3F1EA;
  --green-felt:#0E3B36;
  --signal-white:#FFFFFF;

  --glass:rgba(18,41,61,.66);
  --glass-strong:rgba(9,21,33,.94);
  --line:rgba(140,155,168,.22);
  --line-strong:rgba(140,155,168,.42);
  --text-soft:rgba(243,241,234,.76);
  --text-dim:rgba(243,241,234,.56);

  --font-display:"Oswald","Arial Narrow","Haettenschweiler","Noto Sans SC","Source Han Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
  --font-body:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-mono:"JetBrains Mono","Roboto Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --max-w:1280px;
  --radius:18px;
  --radius-sm:12px;
  --radius-pill:999px;

  --header-h:146px;

  --ease:cubic-bezier(.22,.61,.36,1);
  --dur:.28s;
}

/* ---------- 2. Reset ---------- */
*,*::before,*::after{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;}
body,h1,h2,h3,h4,h5,p,figure,blockquote,dl,dd{margin:0;}
ul,ol{margin:0;padding:0;list-style:none;}
img,svg,video{display:block;max-width:100%;}
button,input,select,textarea{font:inherit;color:inherit;}
a{color:var(--fluo-cyan);text-decoration:none;transition:color var(--dur) var(--ease),background-color var(--dur) var(--ease),border-color var(--dur) var(--ease);}
a:hover{color:#7BF7DF;}
strong{color:var(--signal-white);font-weight:700;}

/* ---------- 3. 基础与中文排版 ---------- */
body{
  padding-top:var(--header-h);
  background-color:var(--ink-night);
  background-image:
    radial-gradient(900px 620px at 86% -8%, rgba(61,240,207,.10), transparent 62%),
    radial-gradient(760px 560px at 0% 2%, rgba(59,46,126,.30), transparent 60%),
    radial-gradient(720px 520px at 100% 96%, rgba(110,31,46,.20), transparent 64%);
  background-repeat:no-repeat;
  background-attachment:fixed;
  color:var(--sand-paper);
  font-family:var(--font-body);
  font-size:17px;
  line-height:1.75;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
  overflow-x:hidden;
}
:focus-visible{outline:2px solid var(--fluo-cyan);outline-offset:3px;border-radius:6px;}

.skip-link{
  position:absolute;left:16px;top:-80px;z-index:200;
  padding:12px 20px;border-radius:var(--radius-pill);
  background:var(--fluo-cyan);color:var(--ink-night);
  font-size:14px;font-weight:700;
  transition:top var(--dur) var(--ease);
}
.skip-link:focus{top:14px;color:var(--ink-night);}

.scroll-progress{
  position:fixed;left:0;right:0;top:0;height:3px;z-index:120;
  background:rgba(140,155,168,.12);
}
.scroll-progress__bar{
  display:block;height:100%;width:100%;
  transform:scaleX(0);transform-origin:0 50%;
  background:linear-gradient(90deg,var(--fluo-cyan),#6FE6C9 55%,var(--stand-orange));
  will-change:transform;
}

/* ---------- 4. 布局容器 ---------- */
.container{width:min(100% - 2 * clamp(16px,4vw,40px), var(--max-w));margin-inline:auto;}
.container--narrow{width:min(100% - 2 * clamp(16px,4vw,40px), 760px);margin-inline:auto;}

.section{padding-block:clamp(56px,9vw,140px);}
.section--tight{padding-block:clamp(36px,5vw,72px);}
.section--navy{background:var(--pitch-navy);}
.section--indigo{background:var(--indigo-deep);}
.section--wine{background:var(--wine-deep);}
.section--felt{background:var(--green-felt);}
.section--paper{background:var(--sand-paper);color:#17303F;}
.section--paper h1,.section--paper h2,.section--paper h3,.section--paper .display,.section--paper .h2,.section--paper .h3{color:var(--ink-night);}
.section--paper a{color:#0B6B60;}
.section--paper a:hover{color:#0E8A7B;}
.section--paper .lede{color:#41586A;}
.section--paper .card__text{color:#41586A;}

/* ---------- 5. 栅格 ---------- */
.grid{display:grid;gap:clamp(20px,3vw,40px);}
.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:5fr 7fr;}
.grid--split-alt{grid-template-columns:4fr 8fr;}
.grid--12{grid-template-columns:repeat(12,minmax(0,1fr));}
.col-4{grid-column:span 4;}
.col-5{grid-column:span 5;}
.col-7{grid-column:span 7;}
.col-8{grid-column:span 8;}
.col-12{grid-column:span 12;}

/* ---------- 6. 文字层级 ---------- */
.display{
  font-family:var(--font-display);
  font-weight:700;
  font-size:clamp(40px,7vw,96px);
  line-height:1.02;
  letter-spacing:-.01em;
}
.h2{
  font-family:var(--font-display);
  font-weight:700;
  font-size:clamp(28px,4vw,48px);
  line-height:1.08;
  letter-spacing:0;
}
.h3{font-size:clamp(19px,2.2vw,26px);font-weight:700;line-height:1.32;}
.lede{
  font-size:clamp(16px,1.5vw,19px);
  line-height:1.8;
  color:var(--text-soft);
  max-width:38ch;
}
.eyebrow{
  display:inline-flex;align-items:center;gap:10px;
  font-family:var(--font-mono);
  font-size:12px;letter-spacing:.18em;text-transform:uppercase;
  color:var(--mountain-mist);
}
.eyebrow::before{content:"";width:22px;height:1px;background:currentColor;opacity:.75;}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums;letter-spacing:.02em;}
.prose{max-width:36em;font-size:17px;line-height:1.75;}
.prose p + p{margin-top:1.1em;}
.prose ul{list-style:disc;padding-left:1.15em;margin-block:.6em;}
.prose li + li{margin-top:.35em;}

/* ---------- 7. 标签 / 图例 / 坐标 / 数据 ---------- */
.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:4px 10px;border-radius:6px;
  font-family:var(--font-mono);
  font-size:12px;letter-spacing:.14em;text-transform:uppercase;
  background:rgba(61,240,207,.14);
  color:var(--fluo-cyan);
  border:1px solid rgba(61,240,207,.30);
}
.tag--orange{background:rgba(255,122,47,.16);color:#FFB27A;border-color:rgba(255,122,47,.36);}
.tag--mist{background:rgba(140,155,168,.14);color:#C3CDD6;border-color:rgba(140,155,168,.30);}

.legend{display:flex;flex-wrap:wrap;gap:16px;}
.legend__item{display:inline-flex;align-items:center;gap:8px;font-size:13px;letter-spacing:.04em;color:var(--mountain-mist);}
.legend__dot{width:10px;height:10px;border-radius:3px;background:var(--fluo-cyan);box-shadow:0 0 0 3px rgba(61,240,207,.16);}
.legend__dot--orange{background:var(--stand-orange);box-shadow:0 0 0 3px rgba(255,122,47,.18);}
.legend__dot--indigo{background:#7C6BE0;box-shadow:0 0 0 3px rgba(124,107,224,.18);}
.legend__dot--wine{background:#C0566B;box-shadow:0 0 0 3px rgba(192,86,107,.18);}
.legend__dot--mist{background:var(--mountain-mist);box-shadow:0 0 0 3px rgba(140,155,168,.16);}

.coord{font-family:var(--font-mono);font-size:12px;letter-spacing:.16em;color:var(--fluo-cyan);}
.coord--muted{color:var(--mountain-mist);}

.stat{display:flex;flex-direction:column;gap:6px;}
.stat__value{
  font-family:var(--font-mono);font-weight:700;line-height:1;
  font-size:clamp(24px,3.4vw,40px);
  color:var(--fluo-cyan);
}
.stat__label{font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;text-transform:uppercase;color:var(--mountain-mist);}

.rule{height:1px;border:0;background:var(--line);}
.ticks{
  height:14px;
  border-bottom:1px solid var(--line);
  background-image:repeating-linear-gradient(90deg,var(--line-strong) 0 1px,transparent 1px 24px);
}

/* ---------- 8. 面板 / 卡片 / 玻璃层 ---------- */
.glass{
  background:var(--glass);
  border:1px solid var(--line);
  border-radius:var(--radius);
  -webkit-backdrop-filter:blur(14px) saturate(1.2);
  backdrop-filter:blur(14px) saturate(1.2);
}
.panel{
  background:var(--pitch-navy);
  border:1px solid var(--line);
  border-radius:var(--radius);
  padding:clamp(20px,3vw,32px);
}
.panel--paper{background:var(--sand-paper);color:#17303F;border-color:rgba(18,41,61,.14);}

.card{
  position:relative;
  display:flex;flex-direction:column;gap:12px;
  padding:clamp(20px,2.4vw,28px);
  border-radius:var(--radius);
  background:rgba(18,41,61,.72);
  border:1px solid var(--line);
  transition:border-color var(--dur) var(--ease),background-color var(--dur) var(--ease),transform var(--dur) var(--ease);
}
.card:hover{border-color:rgba(61,240,207,.40);background:rgba(18,41,61,.92);}
.card__meta{font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;text-transform:uppercase;color:var(--mountain-mist);}
.card__title{font-size:19px;font-weight:700;line-height:1.4;color:var(--signal-white);}
.card__text{font-size:15px;line-height:1.75;color:var(--text-soft);}
.section--paper .card{background:#FBFAF6;border-color:rgba(18,41,61,.14);}
.section--paper .card__title{color:var(--ink-night);}

/* ---------- 9. 按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:12px 22px;border-radius:var(--radius-pill);
  font-size:15px;font-weight:700;letter-spacing:.02em;
  border:1px solid transparent;cursor:pointer;text-align:center;
  transition:transform var(--dur) var(--ease),background-color var(--dur) var(--ease),color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.btn--primary{background:var(--stand-orange);color:#1A0C04;box-shadow:0 10px 26px rgba(255,122,47,.26);}
.btn--primary:hover{background:#FF9257;color:#1A0C04;transform:translateY(-1px);}
.btn--ghost{background:rgba(61,240,207,.08);color:var(--fluo-cyan);border-color:rgba(61,240,207,.40);}
.btn--ghost:hover{background:rgba(61,240,207,.16);color:#8DF9E5;}
.btn--quiet{background:transparent;color:var(--sand-paper);border-color:var(--line-strong);}
.btn--quiet:hover{border-color:var(--fluo-cyan);color:var(--fluo-cyan);}
.btn--sm{padding:9px 18px;font-size:14px;}
.btn--block{width:100%;}

/* ---------- 10. 页头 ---------- */
.site-header{
  position:fixed;left:0;right:0;top:0;z-index:110;
  padding:10px clamp(12px,3vw,28px) 0;
  pointer-events:none;
}
.site-header__inner{
  position:relative;
  pointer-events:auto;
  max-width:var(--max-w);
  margin:0 auto;
  display:flex;align-items:center;gap:clamp(10px,2vw,20px);
  padding:8px 10px 8px 14px;
  border-radius:var(--radius-pill);
  background:var(--glass);
  border:1px solid var(--line);
  box-shadow:0 18px 44px rgba(3,9,16,.55);
  -webkit-backdrop-filter:blur(16px) saturate(1.25);
  backdrop-filter:blur(16px) saturate(1.25);
  transition:padding var(--dur) var(--ease),background-color var(--dur) var(--ease);
}
.site-header[data-scrolled="true"] .site-header__inner{
  padding:4px 10px 4px 12px;
  background:rgba(9,21,33,.90);
}
.site-header__actions{display:flex;align-items:center;gap:8px;flex:0 0 auto;}

.brand{display:inline-flex;align-items:center;gap:10px;flex:0 0 auto;color:var(--sand-paper);}
.brand:hover{color:var(--sand-paper);}
.brand__mark{
  display:grid;place-items:center;
  width:42px;height:42px;border-radius:14px;
  background:linear-gradient(150deg,var(--fluo-cyan),#1FA9A0 58%,var(--pitch-navy));
  color:var(--ink-night);
  font-family:var(--font-mono);font-weight:700;font-size:13px;letter-spacing:.02em;
  box-shadow:inset 0 0 0 1px rgba(255,255,255,.28);
  flex:0 0 auto;
}
.brand__text{display:flex;flex-direction:column;line-height:1.15;min-width:0;}
.brand__name{font-family:var(--font-display);font-weight:700;font-size:20px;letter-spacing:.02em;}
.brand__line{
  font-size:11px;letter-spacing:.16em;color:var(--mountain-mist);
  transition:opacity var(--dur) var(--ease);
}
.site-header[data-scrolled="true"] .brand__line{opacity:0;}

.nav-toggle{
  display:none;align-items:center;gap:8px;
  padding:9px 14px;border-radius:var(--radius-pill);
  background:rgba(61,240,207,.10);
  border:1px solid rgba(61,240,207,.34);
  color:var(--fluo-cyan);
  font-size:13px;letter-spacing:.12em;cursor:pointer;
}
.nav-toggle__bars{display:inline-flex;flex-direction:column;justify-content:center;gap:4px;width:16px;height:14px;}
.nav-toggle__bars span{display:block;height:2px;width:100%;border-radius:2px;background:currentColor;transition:transform var(--dur) var(--ease),opacity var(--dur) var(--ease);}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(1){transform:translateY(6px) rotate(45deg);}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(2){opacity:0;}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(3){transform:translateY(-6px) rotate(-45deg);}
.nav-toggle__label{font-weight:700;}

.site-nav{margin-left:auto;}
.site-nav__list{display:flex;align-items:center;gap:2px;}
.site-nav__link{
  display:inline-block;
  padding:9px 13px;border-radius:var(--radius-pill);
  color:var(--sand-paper);font-size:14.5px;letter-spacing:.02em;
  border:1px solid transparent;white-space:nowrap;
}
.site-nav__link:hover{color:var(--fluo-cyan);background:rgba(61,240,207,.08);border-color:rgba(61,240,207,.24);}
.site-nav__link[aria-current="page"]{
  background:var(--fluo-cyan);color:var(--ink-night);border-color:transparent;font-weight:700;
}
.site-nav__link[aria-current="page"]:hover{color:var(--ink-night);background:#7BF7DF;}

.quick-switch{
  max-width:var(--max-w);
  margin:8px auto 0;
  display:flex;align-items:center;justify-content:flex-end;gap:8px;
  pointer-events:none;
}
.quick-switch__tag{
  pointer-events:auto;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.16em;text-transform:uppercase;
  color:var(--mountain-mist);
  padding:0 4px;
}
.quick-switch__list{
  pointer-events:auto;
  display:flex;align-items:center;gap:4px;
  padding:4px;border-radius:var(--radius-pill);
  background:rgba(18,41,61,.60);
  border:1px solid var(--line);
  -webkit-backdrop-filter:blur(12px);
  backdrop-filter:blur(12px);
  overflow-x:auto;
  scrollbar-width:none;
  max-width:100%;
}
.quick-switch__list::-webkit-scrollbar{display:none;}
.quick-switch__item{
  display:inline-flex;align-items:center;gap:7px;
  padding:6px 14px;border-radius:var(--radius-pill);
  color:var(--text-soft);font-size:13px;white-space:nowrap;
  border:1px solid transparent;
}
.quick-switch__item:hover{color:var(--fluo-cyan);background:rgba(61,240,207,.10);border-color:rgba(61,240,207,.30);}
.quick-switch__index{font-family:var(--font-mono);font-size:11px;color:var(--mountain-mist);letter-spacing:.08em;}

/* ---------- 11. 面包屑 ---------- */
.breadcrumbs{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.12em;
  color:var(--mountain-mist);
}
.breadcrumbs__item{display:inline-flex;align-items:center;gap:8px;}
.breadcrumbs__item + .breadcrumbs__item::before{content:"/";color:rgba(140,155,168,.45);}
.breadcrumbs a{color:var(--mountain-mist);}
.breadcrumbs a:hover{color:var(--fluo-cyan);}
.breadcrumbs [aria-current="page"]{color:var(--sand-paper);}

/* ---------- 12. 交互组件 ---------- */
.chip-row{display:flex;flex-wrap:wrap;gap:8px;}
.chip{
  display:inline-flex;align-items:center;gap:6px;
  padding:8px 16px;border-radius:var(--radius-pill);
  background:rgba(140,155,168,.10);
  border:1px solid var(--line);
  color:var(--sand-paper);font-size:14px;cursor:pointer;
  transition:color var(--dur) var(--ease),background-color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.chip:hover{border-color:rgba(61,240,207,.40);color:var(--fluo-cyan);}
.chip[aria-pressed="true"],.chip.is-active{background:var(--fluo-cyan);color:var(--ink-night);border-color:transparent;font-weight:700;}

.timeline{display:grid;gap:0;}
.timeline__item{
  position:relative;
  display:grid;grid-template-columns:120px 1fr;gap:20px;
  padding:20px 0 20px 20px;
  border-left:1px dashed var(--line-strong);
}
.timeline__marker{
  position:absolute;left:-6px;top:28px;
  width:11px;height:11px;border-radius:50%;
  background:var(--ink-night);
  border:2px solid var(--fluo-cyan);
}
.timeline__time{font-family:var(--font-mono);font-size:14px;color:var(--fluo-cyan);letter-spacing:.04em;}
.timeline__title{font-size:17px;font-weight:700;color:var(--signal-white);}
.timeline__text{margin-top:6px;font-size:15px;line-height:1.7;color:var(--text-soft);}

.toc{display:flex;flex-wrap:wrap;gap:6px;}
.toc__link{
  display:inline-flex;align-items:center;gap:8px;
  padding:6px 12px;border-radius:var(--radius-pill);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;
  color:var(--mountain-mist);border:1px solid transparent;
}
.toc__link:hover{color:var(--fluo-cyan);}
.toc__link.is-active{color:var(--fluo-cyan);background:rgba(61,240,207,.08);border-color:rgba(61,240,207,.40);}

.copy-btn{
  display:inline-flex;align-items:center;gap:8px;
  padding:6px 12px;border-radius:8px;
  background:rgba(61,240,207,.08);
  border:1px solid rgba(61,240,207,.28);
  color:var(--fluo-cyan);
  font-family:var(--font-mono);font-size:13px;
  cursor:pointer;
  transition:background-color var(--dur) var(--ease),color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.copy-btn[data-copied="true"]{background:var(--fluo-cyan);color:var(--ink-night);border-color:transparent;}

/* ---------- 13. 图片容器（页面阶段放占位图） ---------- */
.media{
  position:relative;overflow:hidden;
  aspect-ratio:16 / 10;
  border-radius:var(--radius);
  border:1px solid var(--line);
  background:linear-gradient(140deg,var(--pitch-navy),var(--ink-night) 70%);
}
.media--wide{aspect-ratio:21 / 9;}
.media--tall{aspect-ratio:4 / 5;}
.media--square{aspect-ratio:1 / 1;}
.media__img{width:100%;height:100%;object-fit:cover;filter:saturate(.94) contrast(1.06);}
.media::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background:linear-gradient(200deg,rgba(61,240,207,.12),transparent 46%,rgba(8,19,31,.58));
}
.media__caption{
  position:absolute;left:16px;bottom:14px;z-index:2;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;
  color:rgba(243,241,234,.88);
}
.media__frame{
  position:absolute;inset:10px;z-index:2;pointer-events:none;
  border:1px dashed rgba(140,155,168,.34);
  border-radius:12px;
}

/* ---------- 14. 显现动画 ---------- */
.js .reveal{opacity:0;transform:translateY(12px);transition:opacity .52s var(--ease),transform .52s var(--ease);}
.js .reveal.is-visible{opacity:1;transform:none;}

/* ---------- 15. 页脚 ---------- */
.site-footer{
  position:relative;
  margin-top:clamp(48px,8vw,120px);
  padding:clamp(40px,6vw,88px) 0 28px;
  background:linear-gradient(180deg,var(--ink-night),#050D16 58%,#03080E);
  border-top:1px solid var(--line);
}
.site-footer__inner{
  width:min(100% - 2 * clamp(16px,4vw,40px), var(--max-w));
  margin-inline:auto;
  display:grid;
  grid-template-columns:minmax(240px,1.05fr) 2fr;
  gap:clamp(28px,4vw,64px);
}
.site-footer__brand{display:flex;flex-direction:column;gap:16px;}
.brand--footer{color:var(--sand-paper);}
.site-footer__tagline{max-width:30ch;font-size:15px;line-height:1.75;color:var(--text-soft);}
.site-footer__meta{display:flex;flex-direction:column;gap:8px;}
.site-footer__meta li{display:flex;align-items:baseline;gap:10px;font-size:13px;}
.meta-key{font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;text-transform:uppercase;color:var(--mountain-mist);min-width:5.4em;}
.meta-val{font-family:var(--font-mono);font-size:13px;color:var(--fluo-cyan);}

.footer-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:clamp(20px,3vw,36px);}
.footer-col__title{
  display:flex;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:12px;font-weight:400;
  letter-spacing:.16em;text-transform:uppercase;
  color:var(--mountain-mist);
  margin-bottom:16px;
}
.footer-col__title::before{content:"";width:14px;height:1px;background:var(--fluo-cyan);}
.footer-col__list{display:flex;flex-direction:column;gap:12px;}
.footer-col__list a{color:var(--text-soft);font-size:15px;}
.footer-col__list a:hover{color:var(--fluo-cyan);}

.site-footer__base{
  width:min(100% - 2 * clamp(16px,4vw,40px), var(--max-w));
  margin:clamp(32px,4vw,56px) auto 0;
  padding-top:20px;
  border-top:1px dashed var(--line-strong);
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px;
}
.site-footer__contact{font-size:13.5px;line-height:1.8;color:var(--text-dim);}
.site-footer__legal{font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--mountain-mist);white-space:nowrap;}

.to-top{
  position:fixed;right:clamp(14px,3vw,28px);bottom:clamp(14px,3vw,28px);z-index:100;
  display:inline-flex;align-items:center;gap:8px;
  padding:11px 18px;border-radius:var(--radius-pill);
  background:rgba(9,21,33,.92);
  border:1px solid rgba(61,240,207,.34);
  color:var(--fluo-cyan);
  font-size:13px;font-weight:700;letter-spacing:.04em;
  cursor:pointer;
  opacity:0;visibility:hidden;transform:translateY(8px);
  transition:opacity var(--dur) var(--ease),transform var(--dur) var(--ease),visibility var(--dur) var(--ease),background-color var(--dur) var(--ease);
}
.to-top[data-visible="true"]{opacity:1;visibility:visible;transform:none;}
.to-top:hover{background:var(--fluo-cyan);color:var(--ink-night);border-color:transparent;}
.to-top__index{font-family:var(--font-mono);font-size:13px;}

/* ---------- 16. 响应式 ---------- */
@media (max-width:1080px){
  :root{--header-h:140px;}
  .nav-toggle{display:inline-flex;}
  .site-header__actions{margin-left:auto;}
  .site-nav{
    position:absolute;left:0;right:0;top:calc(100% + 10px);
    margin:0;padding:14px;
    border-radius:22px;
    background:var(--glass-strong);
    border:1px solid var(--line);
    box-shadow:0 24px 60px rgba(3,9,16,.66);
    -webkit-backdrop-filter:blur(18px);
    backdrop-filter:blur(18px);
    opacity:0;visibility:hidden;transform:translateY(-8px);
    transition:opacity .22s var(--ease),transform .22s var(--ease),visibility .22s var(--ease);
  }
  .site-nav[data-open="true"]{opacity:1;visibility:visible;transform:none;}
  .site-nav__list{flex-direction:column;align-items:stretch;gap:4px;}
  .site-nav__link{display:block;padding:13px 16px;border-radius:14px;font-size:16px;}
  .grid--split,.grid--split-alt{grid-template-columns:1fr;}
  .grid--3{grid-template-columns:repeat(2,minmax(0,1fr));}
  .col-4,.col-5,.col-7,.col-8{grid-column:span 12;}
  .site-footer__inner{grid-template-columns:1fr;}
  .footer-grid{grid-template-columns:repeat(3,minmax(0,1fr));}
}

@media (max-width:820px){
  .grid--2,.grid--3{grid-template-columns:1fr;}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr));}
  .timeline__item{grid-template-columns:1fr;gap:6px;}
  .quick-switch{justify-content:flex-start;}
  .quick-switch__list{-webkit-mask-image:linear-gradient(90deg,#000 88%,transparent);mask-image:linear-gradient(90deg,#000 88%,transparent);}
}

@media (max-width:640px){
  :root{--header-h:130px;}
  body{font-size:16px;background-attachment:scroll;}
  .site-header__cta{display:none;}
  .brand__mark{width:38px;height:38px;border-radius:12px;font-size:12px;}
  .brand__name{font-size:18px;}
  .brand__line{display:none;}
  .footer-grid{grid-template-columns:1fr;}
  .site-footer__base{flex-direction:column;align-items:flex-start;}
  .site-footer__legal{white-space:normal;}
  .to-top{padding:10px 14px;font-size:12px;}
}

@media (max-width:420px){
  :root{--header-h:124px;}
  .quick-switch__tag{display:none;}
}

/* ---------- 17. 无障碍与动效偏好 ---------- */
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  .js .reveal{opacity:1;transform:none;}
  .to-top{transform:none;}
}