/* ============================================================
   冰雪娱乐网 CN站 · /assets/site.css
   共享外壳：reset / 变量 / 中文排版 / 头部 / 页脚 / 通用组件
   ============================================================ */

/* ---------- 1. Reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body,h1,h2,h3,h4,h5,h6,p,ul,ol,li,dl,dt,dd,figure,blockquote{margin:0;padding:0}
ul,ol{list-style:none}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0;cursor:pointer}
img,svg,video{display:block;max-width:100%;height:auto}
table{border-collapse:collapse;width:100%}
[id]{scroll-margin-top:clamp(96px,14vh,150px)}

/* ---------- 2. 变量 ---------- */
:root{
  --c-frost:#F4F7FB;
  --c-mist:#DEEAF8;
  --c-glacier:#4E9BE0;
  --c-navy:#0A1D30;
  --c-deep-ice:#0F3D5C;
  --c-violet:#6C4BFF;
  --c-cyan:#21D8CE;
  --c-amber:#FF9A3C;
  --c-slate:#55677A;
  --c-line:rgba(10,29,48,.18);
  --c-line-soft:rgba(10,29,48,.09);
  --c-frost-line:rgba(244,247,251,.22);
  --font-sans:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Source Han Sans SC","Noto Sans SC",system-ui,-apple-system,"Segoe UI",Arial,sans-serif;
  --font-mono:ui-monospace,"JetBrains Mono","SFMono-Regular",Menlo,Consolas,"Courier New",monospace;
  --r-sm:6px;
  --r-md:14px;
  --r-lg:28px;
  --w-page:1240px;
  --pad-x:clamp(18px,4vw,56px);
  --sec-gap:clamp(72px,9vw,120px);
  --ease:cubic-bezier(.2,.8,.2,1);
  --dur:220ms;
  --header-h:96px;
}

/* ---------- 3. 基础与中文排版 ---------- */
body{
  font-family:var(--font-sans);
  font-size:17px;
  line-height:1.85;
  letter-spacing:.01em;
  color:var(--c-navy);
  background-color:var(--c-frost);
  min-height:100vh;
  overflow-x:hidden;
}
body::before{
  content:"";
  position:fixed;
  inset:0;
  z-index:-1;
  pointer-events:none;
  background:
    radial-gradient(58% 42% at 88% 4%, rgba(108,75,255,.12), rgba(108,75,255,0) 62%),
    radial-gradient(52% 40% at 4% 34%, rgba(33,216,206,.12), rgba(33,216,206,0) 66%),
    radial-gradient(72% 52% at 52% 106%, rgba(78,155,224,.16), rgba(78,155,224,0) 72%);
}
strong,b{font-weight:800}
:focus-visible{outline:3px solid var(--c-violet);outline-offset:3px;border-radius:4px}
::selection{background:rgba(33,216,206,.36);color:var(--c-navy)}

/* ---------- 4. 布局容器 ---------- */
.container{width:100%;max-width:var(--w-page);margin-inline:auto;padding-inline:var(--pad-x)}
.section{padding-block:var(--sec-gap)}
.section--tight{padding-block:clamp(36px,5vw,64px)}

.grid{display:grid;grid-template-columns:repeat(12,minmax(0,1fr));gap:clamp(16px,2.4vw,32px)}
.col-3{grid-column:span 3}
.col-4{grid-column:span 4}
.col-5{grid-column:span 5}
.col-6{grid-column:span 6}
.col-7{grid-column:span 7}
.col-8{grid-column:span 8}
.col-9{grid-column:span 9}
.col-12{grid-column:span 12}
.col-offset-1{grid-column-start:2}

/* ---------- 5. 排版零件 ---------- */
.label-en{
  display:inline-block;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.18em;
  text-transform:uppercase;
  color:var(--c-slate);
}
.vertical-note{
  writing-mode:vertical-rl;
  text-orientation:mixed;
  font-size:12px;
  letter-spacing:.3em;
  color:var(--c-glacier);
  line-height:1;
}
.lede{font-size:clamp(17px,1.6vw,20px);line-height:1.8;color:var(--c-slate);max-width:56ch}
.crack-line{
  height:1px;
  border:0;
  background:linear-gradient(90deg,rgba(10,29,48,0) 0%,rgba(10,29,48,.2) 14%,rgba(33,216,206,.62) 50%,rgba(10,29,48,.2) 86%,rgba(10,29,48,0) 100%);
}

.prose{max-width:68ch;font-size:16.5px;line-height:1.85}
.prose p+p{margin-top:1.05em}
.prose h2{font-size:clamp(22px,3vw,30px);font-weight:900;letter-spacing:-.01em;margin-top:1.9em;margin-bottom:.6em}
.prose h3{font-size:19px;font-weight:800;margin-top:1.6em;margin-bottom:.4em}
.prose ul{margin-top:.8em;display:grid;gap:.55em}
.prose li{position:relative;padding-left:1.15em}
.prose li::before{content:"";position:absolute;left:0;top:.72em;width:7px;height:7px;border-radius:2px;background:var(--c-cyan);transform:rotate(45deg)}
.prose a{color:var(--c-deep-ice);text-decoration:underline;text-decoration-color:var(--c-cyan);text-underline-offset:3px}

/* ---------- 6. 章节头 ---------- */
.chapter{display:flex;align-items:flex-start;gap:clamp(14px,2vw,28px);margin-bottom:clamp(28px,4vw,48px)}
.chapter__num{font-family:var(--font-mono);font-size:13px;letter-spacing:.2em;color:var(--c-glacier);padding-top:.5em;flex:0 0 auto}
.chapter__body{min-width:0}
.chapter__title{font-size:clamp(28px,4.4vw,48px);font-weight:900;line-height:1.15;letter-spacing:-.02em;text-shadow:0 1px 0 rgba(244,247,251,.9)}
.chapter__note{margin-top:.7em;font-size:14.5px;line-height:1.8;color:var(--c-slate);max-width:54ch}

/* ---------- 7. 按钮与状态件 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:9px 18px;border-radius:999px;border:1px solid transparent;
  font-size:13.5px;font-weight:700;letter-spacing:.02em;white-space:nowrap;
  transition:transform var(--dur) var(--ease),background-color var(--dur) var(--ease),color var(--dur) var(--ease),border-color var(--dur) var(--ease),box-shadow var(--dur) var(--ease);
}
.btn--solid{background:var(--c-navy);color:var(--c-frost);box-shadow:0 16px 30px -22px rgba(10,29,48,.95)}
.btn--solid:hover{background:var(--c-deep-ice);transform:translateY(-2px)}
.btn--line{
  border-color:var(--c-cyan);color:var(--c-deep-ice);
  background:linear-gradient(140deg,rgba(33,216,206,.18),rgba(255,255,255,0));
}
.btn--line:hover{border-color:var(--c-violet);color:var(--c-navy);transform:translateY(-2px)}
.btn--amber{background:var(--c-amber);color:#301700;box-shadow:0 16px 30px -22px rgba(255,154,60,.9)}
.btn--amber:hover{transform:translateY(-2px)}
.btn--quiet{border-color:var(--c-line);color:var(--c-slate);padding:7px 14px;font-size:12.5px}
.btn--quiet:hover{border-color:var(--c-glacier);color:var(--c-navy)}

.copy-btn{
  justify-self:start;
  display:inline-flex;align-items:center;gap:6px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;text-transform:uppercase;
  padding:4px 10px;border:1px solid var(--c-frost-line);border-radius:999px;
  color:var(--c-cyan);background:rgba(33,216,206,.1);
  transition:border-color var(--dur) var(--ease),color var(--dur) var(--ease),background-color var(--dur) var(--ease);
}
.copy-btn:hover{border-color:var(--c-cyan);background:rgba(33,216,206,.2)}
.copy-btn[data-copied="true"]{border-color:var(--c-amber);color:var(--c-amber);background:rgba(255,154,60,.14)}
.copy-btn[data-copied="false"]{border-color:#FF7A7A;color:#FFB3B3;background:rgba(255,122,122,.12)}
.copy-status{display:block;font-size:11.5px;letter-spacing:.06em;color:var(--c-cyan)}
.copy-status:empty{display:none}

/* ---------- 8. 卡片 / 图片容器 / 数字 ---------- */
.card{
  position:relative;
  background:rgba(255,255,255,.74);
  border:1px solid var(--c-line-soft);
  border-radius:var(--r-md);
  padding:clamp(18px,2.4vw,28px);
  transition:transform var(--dur) var(--ease),box-shadow var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.card:hover{transform:translateY(-4px);border-color:rgba(33,216,206,.6);box-shadow:0 30px 54px -44px rgba(10,29,48,.9)}
.card--offset{margin-top:clamp(12px,3vw,40px)}
.card--violet{border-left:3px solid var(--c-violet);background:linear-gradient(150deg,rgba(108,75,255,.09),rgba(255,255,255,.8))}
.card--cool{border-left:3px solid var(--c-slate);background:linear-gradient(150deg,rgba(222,234,248,.8),rgba(255,255,255,.55))}
.card__meta{display:block;font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;color:var(--c-slate);margin-bottom:.5em}
.card__title{font-size:clamp(18px,2vw,22px);font-weight:800;line-height:1.45}
.card__body{margin-top:.55em;font-size:15px;line-height:1.8;color:var(--c-slate)}

.frost-frame{
  position:relative;display:block;overflow:hidden;isolation:isolate;
  aspect-ratio:16/9;
  border-radius:var(--r-md);
  border:1px solid rgba(10,29,48,.1);
  background:
    radial-gradient(120% 90% at 12% 6%, rgba(255,255,255,.92), rgba(255,255,255,0) 62%),
    radial-gradient(90% 70% at 88% 94%, rgba(108,75,255,.22), rgba(108,75,255,0) 70%),
    radial-gradient(72% 62% at 70% 18%, rgba(33,216,206,.22), rgba(33,216,206,0) 72%),
    linear-gradient(160deg,var(--c-mist),#EAF2FB 55%,#D7E7F7);
  box-shadow:0 34px 64px -52px rgba(10,29,48,.9);
}
.frost-frame::after{
  content:"";position:absolute;inset:0;pointer-events:none;opacity:.55;
  background-image:
    repeating-linear-gradient(115deg, rgba(255,255,255,.6) 0 2px, rgba(255,255,255,0) 2px 9px),
    repeating-linear-gradient(64deg, rgba(15,61,92,.06) 0 1px, rgba(15,61,92,0) 1px 7px);
}
.frost-frame--flat{box-shadow:none;background:linear-gradient(160deg,var(--c-mist),#E8F0FA)}
.frost-frame--ratio-21x9{aspect-ratio:21/9}
.frost-frame--ratio-16x9{aspect-ratio:16/9}
.frost-frame--ratio-4x3{aspect-ratio:4/3}
.frost-frame--ratio-1x1{aspect-ratio:1/1}
.frost-frame--ratio-3x4{aspect-ratio:3/4}
.frost-frame__media{position:absolute;inset:0;z-index:1}
.frost-frame__media img{width:100%;height:100%;object-fit:cover;object-position:center}
.frost-frame__caption{
  position:absolute;left:0;right:0;bottom:0;z-index:2;
  padding:14px 16px;font-size:12.5px;line-height:1.6;color:var(--c-navy);
  background:linear-gradient(180deg,rgba(244,247,251,0),rgba(244,247,251,.94) 58%);
}

.stat{display:block}
.stat__num{display:block;font-family:var(--font-mono);font-size:clamp(28px,4vw,44px);font-weight:700;letter-spacing:-.01em;color:var(--c-deep-ice);line-height:1.2}
.stat__num--hot{color:var(--c-amber)}
.stat__label{display:block;margin-top:.35em;font-size:12px;letter-spacing:.16em;color:var(--c-slate)}

.callout{
  border:1px solid var(--c-line-soft);
  border-left:3px solid var(--c-cyan);
  border-radius:var(--r-md);
  padding:clamp(18px,2.6vw,26px);
  background:linear-gradient(140deg,rgba(222,234,248,.88),rgba(244,247,251,.62));
}
.callout--violet{border-left-color:var(--c-violet)}
.callout__title{font-size:16px;font-weight:800;margin-bottom:.4em}

/* ---------- 9. 面包屑 ---------- */
.breadcrumb{padding-block:18px;font-size:12.5px;color:var(--c-slate)}
.breadcrumb__list{display:flex;flex-wrap:wrap;align-items:center;gap:8px}
.breadcrumb__item{display:inline-flex;align-items:center;gap:8px}
.breadcrumb__item::after{content:"/";color:var(--c-line)}
.breadcrumb__item:last-child::after{content:""}
.breadcrumb__link{text-decoration:underline;text-decoration-color:rgba(78,155,224,.55);text-underline-offset:3px}
.breadcrumb__link:hover{color:var(--c-navy)}
.breadcrumb__current{color:var(--c-navy);font-weight:700}

/* ---------- 10. 筛选标签 ---------- */
.chip-group{display:flex;flex-wrap:wrap;gap:8px}
.chip{
  display:inline-flex;align-items:center;gap:6px;
  padding:6px 14px;border-radius:999px;
  border:1px solid var(--c-line);
  background:rgba(255,255,255,.72);
  font-size:13px;color:var(--c-slate);
  transition:transform var(--dur) var(--ease),border-color var(--dur) var(--ease),color var(--dur) var(--ease),background-color var(--dur) var(--ease);
}
.chip:hover{border-color:var(--c-glacier);color:var(--c-navy);transform:translateY(-1px)}
.chip[aria-pressed="true"]{
  border-color:var(--c-cyan);color:var(--c-deep-ice);font-weight:700;
  background:linear-gradient(140deg,rgba(33,216,206,.2),rgba(255,255,255,.9));
  box-shadow:0 10px 22px -18px rgba(33,216,206,.95);
}
[data-hidden]{display:none}

/* ---------- 11. 分段控件（新旧对照） ---------- */
.segmented{
  display:inline-flex;gap:4px;padding:4px;
  border:1px solid var(--c-line);border-radius:999px;
  background:rgba(222,234,248,.62);
}
.segmented__btn{
  padding:8px 18px;border-radius:999px;
  font-size:13.5px;font-weight:700;color:var(--c-slate);
  transition:background-color var(--dur) var(--ease),color var(--dur) var(--ease);
}
.segmented__btn:hover{color:var(--c-navy)}
.segmented__btn[aria-selected="true"]{background:var(--c-navy);color:var(--c-frost)}
.segmented__panel{display:none;padding-top:clamp(20px,3vw,32px)}
.segmented__panel[data-active]{display:block;animation:panel-in 240ms var(--ease) both}
@keyframes panel-in{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}

/* ---------- 12. 时间轴 ---------- */
.timeline{--tl-pad:clamp(22px,4vw,44px);position:relative;padding-left:var(--tl-pad)}
.timeline::before{
  content:"";position:absolute;left:5px;top:10px;bottom:10px;width:2px;
  background:linear-gradient(180deg,var(--c-glacier),rgba(33,216,206,.7) 55%,rgba(108,75,255,.55));
}
.timeline__item{position:relative;padding-bottom:clamp(24px,3.5vw,40px)}
.timeline__dot{
  position:absolute;left:calc(-1 * var(--tl-pad));top:9px;
  width:12px;height:12px;border-radius:50%;
  background:var(--c-frost);border:2px solid var(--c-glacier);
  transition:transform var(--dur) var(--ease),background-color var(--dur) var(--ease),border-color var(--dur) var(--ease),box-shadow var(--dur) var(--ease);
}
.timeline__item[data-active] .timeline__dot{
  transform:scale(1.15);background:var(--c-cyan);border-color:var(--c-cyan);
  box-shadow:0 0 0 6px rgba(33,216,206,.18);
}
.timeline__body{min-width:0}

/* ---------- 13. 锚点索引 ---------- */
.anchor-index{position:sticky;top:calc(var(--header-h) + 24px);display:flex;flex-direction:column;gap:10px;font-size:12px}
.anchor-index__link{
  padding-left:12px;border-left:2px solid var(--c-line);
  letter-spacing:.08em;color:var(--c-slate);
  transition:color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.anchor-index__link:hover{color:var(--c-navy)}
.anchor-index__link[aria-current="true"]{color:var(--c-navy);font-weight:700;border-left-color:var(--c-violet)}

/* ---------- 14. 显现 ---------- */
[data-reveal-ready] .reveal{opacity:0;transform:translateY(12px)}
[data-reveal-ready] .reveal.is-in{
  opacity:1;transform:none;
  transition:opacity 240ms var(--ease),transform 240ms var(--ease);
}

/* ---------- 15. 头部 ---------- */
.site-header{
  position:sticky;top:0;z-index:60;
  background:rgba(244,247,251,.84);
  backdrop-filter:blur(16px) saturate(140%);
  -webkit-backdrop-filter:blur(16px) saturate(140%);
  border-bottom:1px solid var(--c-line-soft);
  transition:background-color 240ms var(--ease),box-shadow 240ms var(--ease);
}
.site-header[data-scrolled]{background:rgba(244,247,251,.97);box-shadow:0 24px 46px -40px rgba(10,29,48,.9)}
.site-header[data-scrolled] .frost-strip{display:none}

.skip-link{
  position:absolute;left:12px;top:-56px;z-index:90;
  padding:10px 18px;border-radius:var(--r-sm);
  background:var(--c-navy);color:var(--c-frost);
  font-size:13px;font-weight:700;
  transition:top 200ms var(--ease);
}
.skip-link:focus{top:10px}

.frost-strip{
  max-width:var(--w-page);margin-inline:auto;
  padding:9px var(--pad-x) 0;
  display:flex;align-items:center;justify-content:space-between;gap:16px;
}
.frost-strip__note{
  font-size:11px;letter-spacing:.2em;color:var(--c-slate);
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
}
.utility-links{display:flex;align-items:center;gap:18px}
.utility-link{
  font-size:12px;letter-spacing:.1em;color:var(--c-slate);
  padding-bottom:2px;border-bottom:1px solid transparent;
  transition:color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.utility-link:hover{color:var(--c-deep-ice);border-bottom-color:var(--c-cyan)}

.command-bar{
  max-width:var(--w-page);margin-inline:auto;
  padding:8px var(--pad-x) 12px;
  display:grid;grid-template-columns:auto minmax(0,1fr) auto;
  align-items:center;gap:clamp(12px,2vw,32px);
  transition:padding 240ms var(--ease);
}
.site-header[data-scrolled] .command-bar{padding-block:6px 8px}

.brand{display:flex;align-items:center;gap:12px;flex:0 0 auto}
.brand__mark{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.12em;
  padding:6px 9px;border:1px solid var(--c-navy);border-radius:var(--r-sm);
  color:var(--c-navy);
  background:linear-gradient(140deg,rgba(33,216,206,.26),rgba(108,75,255,.2));
}
.brand__stack{display:flex;flex-direction:column;line-height:1.25}
.brand__name{font-size:16px;font-weight:900;letter-spacing:.02em}
.brand__tagline{font-size:11px;letter-spacing:.16em;color:var(--c-slate)}
.site-header[data-scrolled] .brand__tagline{display:none}

.site-nav{min-width:0}
.site-nav__list{
  display:flex;align-items:center;gap:2px;
  overflow-x:auto;scrollbar-width:none;-ms-overflow-style:none;
}
.site-nav__list::-webkit-scrollbar{display:none}
.site-nav__item{flex:0 0 auto}
.nav-link{
  position:relative;
  display:inline-flex;align-items:baseline;gap:6px;
  padding:8px 10px;border-radius:var(--r-sm);
  font-size:14px;font-weight:600;color:var(--c-navy);
  white-space:nowrap;
  transition:color var(--dur) var(--ease),background-color var(--dur) var(--ease);
}
.nav-link__index{font-family:var(--font-mono);font-size:10px;letter-spacing:.05em;color:var(--c-glacier)}
.nav-link__label{line-height:1.4}
.nav-link::after{
  content:"";position:absolute;left:10px;right:10px;bottom:3px;height:2px;border-radius:2px;
  background:var(--c-cyan);transform:scaleX(0);transform-origin:left;
  transition:transform var(--dur) var(--ease),background-color var(--dur) var(--ease);
}
.nav-link:hover{color:var(--c-deep-ice)}
.nav-link:hover::after{transform:scaleX(1)}
.nav-link[aria-current="page"]{
  color:var(--c-navy);
  background:linear-gradient(180deg,rgba(108,75,255,.12),rgba(33,216,206,.12));
}
.nav-link[aria-current="page"] .nav-link__index{color:var(--c-amber)}
.nav-link[aria-current="page"]::after{transform:scaleX(1);background:var(--c-violet)}

.command-bar__tail{display:flex;align-items:center;gap:10px}
.command-actions{display:flex;align-items:center;gap:8px}

.nav-toggle{
  display:none;align-items:center;gap:9px;
  padding:8px 14px;border:1px solid var(--c-line);border-radius:999px;
  font-size:12px;letter-spacing:.16em;color:var(--c-navy);
  background:rgba(255,255,255,.78);
  transition:border-color var(--dur) var(--ease),color var(--dur) var(--ease);
}
.nav-toggle:hover{border-color:var(--c-cyan)}
.nav-toggle__bars{position:relative;display:block;width:16px;height:2px;border-radius:2px;background:var(--c-deep-ice);transition:background-color var(--dur) var(--ease)}
.nav-toggle__bars::before,.nav-toggle__bars::after{
  content:"";position:absolute;left:0;width:16px;height:2px;border-radius:2px;
  background:var(--c-deep-ice);
  transition:top 220ms var(--ease),transform 220ms var(--ease),background-color var(--dur) var(--ease);
}
.nav-toggle__bars::before{top:-5px}
.nav-toggle__bars::after{top:5px}
.site-header[data-open] .nav-toggle{border-color:var(--c-cyan);color:var(--c-deep-ice)}
.site-header[data-open] .nav-toggle__bars{background:transparent}
.site-header[data-open] .nav-toggle__bars::before,
.site-header[data-open] .nav-toggle__bars::after{top:0;background:var(--c-violet)}
.site-header[data-open] .nav-toggle__bars::before{transform:rotate(45deg)}
.site-header[data-open] .nav-toggle__bars::after{transform:rotate(-45deg)}

.scroll-progress{height:3px;background:linear-gradient(90deg,rgba(78,155,224,.16),rgba(108,75,255,.16))}
.scroll-progress__bar{
  display:block;height:100%;width:0;
  background:linear-gradient(90deg,var(--c-glacier),var(--c-cyan) 58%,var(--c-violet));
  transition:width 120ms linear;
}

/* ---------- 16. 页脚 ---------- */
.site-footer{
  position:relative;isolation:isolate;overflow:hidden;
  margin-top:var(--sec-gap);
  color:var(--c-mist);
  background:linear-gradient(180deg,var(--c-deep-ice) 0%,#0B2C41 46%,#071B29 100%);
}
.site-footer::before{
  content:"";position:absolute;inset:0;z-index:-1;pointer-events:none;
  background-image:
    repeating-linear-gradient(58deg,rgba(244,247,251,.05) 0 1px,rgba(244,247,251,0) 1px 6px),
    repeating-linear-gradient(-40deg,rgba(33,216,206,.055) 0 1px,rgba(33,216,206,0) 1px 9px);
}
.footer__glow{
  position:absolute;z-index:-1;pointer-events:none;
  width:60vw;height:60vw;max-width:820px;max-height:820px;
  right:-16vw;top:-26vw;
  background:radial-gradient(circle at 50% 50%,rgba(108,75,255,.34),rgba(108,75,255,0) 62%);
}
.footer__inner{
  position:relative;
  display:grid;
  grid-template-columns:minmax(0,1.05fr) minmax(0,1.5fr) minmax(0,.95fr);
  gap:clamp(28px,4vw,56px);
  padding-block:clamp(48px,7vw,88px);
}
.footer__lead{min-width:0}
.footer__brand{display:inline-flex;align-items:center;gap:12px;margin-bottom:16px}
.footer__mark{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.16em;
  padding:6px 9px;border-radius:var(--r-sm);color:var(--c-navy);
  background:linear-gradient(140deg,var(--c-cyan),var(--c-glacier));
}
.footer__name{font-size:18px;font-weight:900;letter-spacing:.02em;color:#FFFFFF}
.footer__summary{font-size:14.5px;line-height:1.9;color:rgba(222,234,248,.8);max-width:42ch}
.footer__nav{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:clamp(18px,3vw,36px)}
.footer__col{min-width:0}
.footer__col-title{
  font-family:var(--font-mono);font-size:12px;font-weight:700;
  letter-spacing:.22em;text-transform:uppercase;color:var(--c-cyan);
  margin-bottom:14px;
}
.footer__links{display:grid;gap:9px}
.footer__link{
  width:fit-content;font-size:14.5px;color:rgba(222,234,248,.88);
  border-bottom:1px solid transparent;
  transition:color var(--dur) var(--ease),border-color var(--dur) var(--ease);
}
.footer__link:hover{color:#FFFFFF;border-bottom-color:var(--c-cyan)}
.footer__contact{min-width:0}
.footer__contact-list{display:grid;gap:16px}
.footer__contact-item{display:grid;gap:5px;justify-items:start}
.footer__contact-key{font-family:var(--font-mono);font-size:11px;letter-spacing:.18em;color:rgba(33,216,206,.9)}
.footer__contact-value{font-size:14px;line-height:1.7;color:#E9F2FC}
.footer__contact-value--mono{font-family:var(--font-mono);font-size:13.5px;letter-spacing:.02em;word-break:break-all}
.footer__legal{position:relative;border-top:1px solid var(--c-frost-line)}
.footer__legal-inner{
  max-width:var(--w-page);margin-inline:auto;padding:22px var(--pad-x) 30px;
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:8px 28px;
  font-size:12.5px;color:rgba(222,234,248,.68);
}
.footer__icp{font-family:var(--font-mono);letter-spacing:.06em}
.footer__copy{letter-spacing:.04em}

/* ---------- 17. 响应式 ---------- */
@media (max-width:1100px){
  .site-nav__list{gap:0}
  .nav-link{padding:8px 8px;font-size:13.5px}
}

@media (max-width:960px){
  :root{--pad-x:18px;--header-h:76px}
  .command-bar{
    grid-template-columns:minmax(0,1fr) auto;
    align-items:center;
    padding-bottom:10px;
  }
  .brand{grid-column:1;grid-row:1;min-width:0}
  .nav-toggle{display:inline-flex;grid-column:2;grid-row:1;justify-self:end}
  .site-nav{
    grid-column:1 / -1;grid-row:2;
    display:none;
    margin-top:10px;padding-top:12px;
    border-top:1px dashed var(--c-line);
  }
  .command-bar__tail{
    grid-column:1 / -1;grid-row:3;
    display:none;flex-direction:column;align-items:stretch;gap:12px;
    margin-top:14px;padding-top:14px;
    border-top:1px dashed var(--c-line);
  }
  .command-actions{flex-direction:column;align-items:stretch;gap:10px}
  .command-actions .btn{justify-content:center;padding-block:12px}
  .site-nav__list{flex-direction:column;align-items:stretch;gap:2px;overflow:visible}
  .site-nav__item{flex:1 1 auto}
  .nav-link{justify-content:flex-start;padding:11px 12px;border-radius:10px;font-size:15px}
  .nav-link::after{left:12px;right:auto;width:22px;bottom:8px}
  .nav-link__index{font-size:11px}
  .site-header[data-open]{background:rgba(244,247,251,.99);box-shadow:0 34px 60px -42px rgba(10,29,48,.9)}
  .site-header[data-open] .site-nav{display:flex}
  .site-header[data-open] .command-bar__tail{display:flex}

  .grid{gap:18px}
  .col-3,.col-4,.col-5{grid-column:span 6}
  .footer__inner{grid-template-columns:minmax(0,1fr);gap:38px}
  .footer__nav{grid-template-columns:repeat(3,minmax(0,1fr))}
  .anchor-index{position:static;flex-direction:row;flex-wrap:wrap;gap:12px}
}

@media (max-width:720px){
  .frost-strip{justify-content:flex-end}
  .frost-strip__note{display:none}
  .utility-links{gap:14px}
  .brand__tagline{display:none}
}

@media (max-width:640px){
  .col-3,.col-4,.col-5,.col-6,.col-7,.col-8,.col-9{grid-column:span 12}
  .col-offset-1{grid-column-start:auto}
  .footer__nav{grid-template-columns:1fr 1fr;gap:24px}
  .footer__legal-inner{flex-direction:column;align-items:flex-start}
  .chapter{flex-direction:column;gap:8px}
  .chapter__num{padding-top:0}
  .segmented{display:flex;width:100%}
  .segmented__btn{flex:1;text-align:center}
}

/* ---------- 18. 动效偏好与打印 ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  [data-reveal-ready] .reveal{opacity:1;transform:none}
  .scroll-progress__bar{transition:none}
}