/* ============================================================
   完美体育赛 · 冰城数据观赛舱
   /assets/site.css  —— 共享外壳与基础组件
   ============================================================ */

/* ---------- 01 设计令牌 ---------- */
:root{
  --blue-900:#08122B;
  --blue-700:#10224C;
  --blue-500:#1B3A7A;
  --silver-100:#EAF0F9;
  --silver-300:#B7C6DD;
  --silver-500:#7C8DAE;
  --green-400:#4BFF9E;
  --orange-500:#FF7A29;
  --cyan-400:#5FD8F5;
  --ice-white:#F7FAFF;

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

  --wrap:1200px;
  --gutter:clamp(16px,4vw,46px);
  --radius:6px;
  --line:rgba(183,198,221,.18);
  --line-strong:rgba(183,198,221,.34);
  --shadow:0 18px 44px rgba(3,8,20,.55);
}

/* ---------- 02 重置与基底 ---------- */
*,*::before,*::after{box-sizing:border-box}

html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
  scroll-padding-top:158px;
}

body{
  margin:0;
  background-color:var(--blue-900);
  background-image:
    radial-gradient(1100px 620px at 84% -12%,rgba(27,58,122,.55),transparent 62%),
    radial-gradient(900px 520px at -6% 26%,rgba(95,216,245,.10),transparent 68%);
  background-attachment:fixed;
  color:var(--silver-100);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.85;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

img,svg,video{max-width:100%;display:block}
a{color:inherit}
button{font-family:inherit}
ul,ol{margin:0;padding:0}

:focus-visible{outline:2px solid var(--cyan-400);outline-offset:3px;border-radius:3px}
::selection{background:var(--green-400);color:var(--blue-900)}

/* ---------- 03 布局工具 ---------- */
.wrap{
  width:100%;
  max-width:var(--wrap);
  margin-inline:auto;
  padding-inline:var(--gutter);
}

.split{
  display:grid;
  grid-template-columns:minmax(0,.85fr) minmax(0,1.4fr);
  gap:clamp(20px,3.4vw,52px);
  align-items:start;
}
.split--rev{grid-template-columns:minmax(0,1.4fr) minmax(0,.85fr)}

.grid-auto{
  display:grid;
  gap:clamp(14px,2vw,22px);
  grid-template-columns:repeat(auto-fit,minmax(248px,1fr));
}

.stack{display:flex;flex-direction:column;gap:clamp(14px,2vw,22px)}

@media (max-width:900px){
  .split,.split--rev{grid-template-columns:1fr}
}

/* ---------- 04 文字系统 ---------- */
.h-display{
  margin:0;
  font-family:var(--font-display);
  font-weight:900;
  font-size:clamp(34px,6.4vw,72px);
  line-height:1.06;
  letter-spacing:-.02em;
  color:var(--ice-white);
}
.h-section{
  margin:0;
  font-family:var(--font-display);
  font-weight:700;
  font-size:clamp(22px,3.2vw,34px);
  line-height:1.3;
  letter-spacing:-.01em;
  color:var(--ice-white);
}
.lede{
  margin:0;
  max-width:62ch;
  font-size:clamp(15.5px,1.6vw,18px);
  line-height:1.85;
  color:var(--silver-300);
}
.eyebrow{
  margin:0;
  font-size:11px;
  letter-spacing:.3em;
  color:var(--silver-500);
}
.sec-num{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.18em;
  color:var(--cyan-400);
}
.mono{
  font-family:var(--font-mono);
  letter-spacing:.02em;
  font-variant-numeric:tabular-nums;
}
.annotation{
  font-size:11.5px;
  letter-spacing:.3em;
  color:var(--silver-500);
}
.annotation--v{
  writing-mode:vertical-rl;
  text-orientation:mixed;
  letter-spacing:.34em;
}
.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;
}

/* ---------- 05 章节骨架 ---------- */
.section{padding-block:clamp(40px,6vw,84px)}
.section--tight{padding-block:clamp(22px,4vw,48px)}
.section__head{
  display:flex;
  flex-wrap:wrap;
  align-items:flex-end;
  gap:10px 22px;
  margin-bottom:clamp(20px,3vw,36px);
}
.section__head > .lede{flex:1 1 320px}

/* ---------- 06 按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  gap:10px;
  padding:13px 22px;
  border-radius:4px;
  border:1px solid transparent;
  font-family:var(--font-body);
  font-size:14.5px;
  font-weight:700;
  letter-spacing:.08em;
  line-height:1.4;
  text-decoration:none;
  cursor:pointer;
  transition:transform .2s ease,background-color .2s ease,color .2s ease,border-color .2s ease;
}
.btn--primary{background:var(--orange-500);color:var(--blue-900);border-color:var(--orange-500)}
.btn--primary:hover{background:#FF8F45;transform:translateY(-2px)}
.btn--ghost{background:transparent;color:var(--silver-100);border-color:var(--line-strong)}
.btn--ghost:hover{border-color:var(--green-400);color:var(--green-400)}
.btn--quiet{background:rgba(27,58,122,.6);color:var(--ice-white);border-color:rgba(95,216,245,.36)}
.btn--quiet:hover{border-color:var(--cyan-400);color:var(--cyan-400)}

/* ---------- 07 面包屑 ---------- */
.crumbs{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  padding-block:14px;
  font-size:12.5px;
  color:var(--silver-500);
}
.crumbs a{color:var(--silver-300);text-decoration:none}
.crumbs a:hover{color:var(--cyan-400)}
.crumbs__sep{color:var(--blue-500)}
.crumbs [aria-current="page"]{color:var(--silver-100)}

/* ---------- 08 面板：玻璃层 / 实色层 ---------- */
.panel{
  position:relative;
  padding:clamp(18px,2.6vw,30px);
  border:1px solid var(--line);
  border-radius:var(--radius);
  background:rgba(16,34,76,.62);
  -webkit-backdrop-filter:blur(14px);
  backdrop-filter:blur(14px);
}
.panel--ice{
  background:var(--ice-white);
  color:var(--blue-900);
  border-color:rgba(8,18,43,.12);
  -webkit-backdrop-filter:none;
  backdrop-filter:none;
}
.panel--ice .lede{color:#2C3E63}

/* ---------- 09 档案夹 ---------- */
.folder{position:relative;padding-top:34px}
.folder__tab{
  position:absolute;
  top:0;left:0;
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:7px 20px 7px 14px;
  border-radius:6px 14px 0 0;
  background:var(--blue-500);
  color:var(--ice-white);
  font-size:12px;
  letter-spacing:.2em;
  z-index:1;
}
.folder__tab::after{
  content:"";
  position:absolute;
  right:-13px;top:0;
  width:14px;height:100%;
  background:inherit;
  clip-path:polygon(0 0,100% 100%,0 100%);
}
.folder__body{
  padding:clamp(18px,2.4vw,28px);
  border:1px solid var(--line);
  border-radius:0 var(--radius) var(--radius) var(--radius);
  background:rgba(16,34,76,.55);
  -webkit-backdrop-filter:blur(12px);
  backdrop-filter:blur(12px);
}

/* ---------- 10 资料卡 ---------- */
.datacard{
  display:grid;
  gap:14px;
  padding:clamp(16px,2vw,26px);
  border:1px solid rgba(8,18,43,.10);
  border-radius:var(--radius);
  background:var(--ice-white);
  color:var(--blue-900);
}
.datacard__head{
  display:flex;
  justify-content:space-between;
  align-items:flex-start;
  gap:14px;
}
.datacard__title{
  margin:0;
  font-family:var(--font-display);
  font-weight:700;
  font-size:18px;
  line-height:1.45;
  color:var(--blue-900);
}
.datacard__meta{font-family:var(--font-mono);font-size:12px;color:#4A5A7C;white-space:nowrap}
.datacard__body{margin:0;font-size:14.5px;line-height:1.8;color:#2C3E63}
.datacard__foot{display:flex;flex-wrap:wrap;gap:10px;align-items:center}

/* ---------- 11 分类标签 ---------- */
.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:6px 13px;
  border-radius:999px;
  border:1px solid var(--line-strong);
  background:rgba(27,58,122,.5);
  color:var(--silver-300);
  font-family:inherit;
  font-size:12.5px;
  letter-spacing:.06em;
  text-decoration:none;
  cursor:pointer;
  transition:color .2s ease,border-color .2s ease,background-color .2s ease;
}
.tag:hover{color:var(--ice-white);border-color:var(--cyan-400)}
.tag[aria-pressed="true"],
.tag.is-active{
  background:var(--green-400);
  border-color:var(--green-400);
  color:var(--blue-900);
  font-weight:700;
}

/* ---------- 12 等宽数字条 ---------- */
.numstrip{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(122px,1fr));
  gap:1px;
  border:1px solid var(--line);
  border-radius:4px;
  background:var(--line);
  overflow:hidden;
}
.numstrip__cell{
  display:flex;
  flex-direction:column;
  gap:4px;
  padding:14px 16px;
  background:var(--blue-900);
}
.numstrip__value{
  font-family:var(--font-mono);
  font-size:clamp(18px,2.6vw,26px);
  letter-spacing:.02em;
  color:var(--green-400);
}
.numstrip__label{font-size:11.5px;letter-spacing:.2em;color:var(--silver-500)}

/* ---------- 13 步骤条 ---------- */
.stepbar{
  display:grid;
  grid-auto-flow:column;
  grid-auto-columns:1fr;
  gap:6px;
  list-style:none;
}
.stepbar__item{
  padding:14px 14px 12px;
  border-top:2px solid rgba(183,198,221,.25);
  background:rgba(16,34,76,.5);
  color:var(--silver-500);
  font-size:13px;
  line-height:1.6;
}
.stepbar__item[data-active]{
  border-top-color:var(--green-400);
  background:rgba(27,58,122,.66);
  color:var(--ice-white);
}
.stepbar__idx{
  display:block;
  margin-bottom:4px;
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.18em;
  color:var(--cyan-400);
}
@media (max-width:720px){
  .stepbar{grid-auto-flow:row;grid-auto-columns:auto}
}

/* ---------- 14 折叠面板 ---------- */
.fold{
  border:1px solid var(--line);
  border-radius:4px;
  background:rgba(16,34,76,.45);
  overflow:hidden;
}
.fold + .fold{margin-top:10px}
.fold__head{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  width:100%;
  padding:16px 18px;
  border:0;
  background:none;
  color:var(--silver-100);
  font-family:inherit;
  font-size:15.5px;
  font-weight:700;
  line-height:1.6;
  text-align:left;
  cursor:pointer;
  list-style:none;
}
.fold__head::-webkit-details-marker{display:none}
.fold__head:hover{color:var(--cyan-400)}
.fold__head::after{
  content:"＋";
  flex:0 0 auto;
  font-family:var(--font-mono);
  font-size:16px;
  color:var(--cyan-400);
}
.fold[open] .fold__head::after{content:"－"}
.fold__body{
  padding:0 18px 18px;
  color:var(--silver-300);
  font-size:14.5px;
  line-height:1.85;
}

/* ---------- 15 筛选条 ---------- */
.filterbar{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:10px;
  padding:14px;
  border:1px solid var(--line);
  border-radius:var(--radius);
  background:rgba(16,34,76,.55);
  -webkit-backdrop-filter:blur(12px);
  backdrop-filter:blur(12px);
}
.filterbar__input{
  flex:1 1 220px;
  min-width:0;
  padding:10px 14px;
  border:1px solid var(--line-strong);
  border-radius:4px;
  background:rgba(8,18,43,.7);
  color:var(--ice-white);
  font-family:inherit;
  font-size:14.5px;
  line-height:1.5;
}
.filterbar__input::placeholder{color:var(--silver-500)}

/* ---------- 16 章节目录 ---------- */
.toc{
  position:sticky;
  top:158px;
  align-self:start;
}
.toc__title{margin:0 0 12px;font-size:11px;letter-spacing:.28em;color:var(--silver-500)}
.toc__list{list-style:none;border-left:1px solid rgba(183,198,221,.2)}
.toc__link{
  display:block;
  margin-left:-1px;
  padding:7px 0 7px 14px;
  border-left:2px solid transparent;
  color:var(--silver-500);
  font-size:13.5px;
  text-decoration:none;
  transition:color .2s ease,border-color .2s ease;
}
.toc__link:hover{color:var(--ice-white)}
.toc__link[aria-current="true"]{color:var(--green-400);border-left-color:var(--green-400)}
@media (max-width:900px){
  .toc{position:static;top:auto}
}

/* ---------- 17 图片容器基础规则 ---------- */
.media{
  position:relative;
  border:1px solid var(--line);
  border-radius:var(--radius);
  background:linear-gradient(140deg,#10224C,#08122B 62%,#0C1B3E);
  overflow:hidden;
}
.media__frame{
  position:relative;
  display:grid;
  place-items:center;
  aspect-ratio:16/9;
}
.media--tall .media__frame{aspect-ratio:4/5}
.media--wide .media__frame{aspect-ratio:21/9}
.media__frame img{
  position:absolute;
  inset:0;
  width:100%;
  height:100%;
  object-fit:cover;
}
.media__glow{
  position:absolute;
  inset:0;
  pointer-events:none;
  background:
    radial-gradient(520px 220px at 78% 12%,rgba(95,216,245,.20),transparent 65%),
    radial-gradient(420px 200px at 18% 88%,rgba(255,122,41,.14),transparent 68%);
}
.media__cap{
  position:absolute;
  left:0;right:0;bottom:0;
  z-index:2;
  padding:10px 16px;
  font-size:11.5px;
  letter-spacing:.16em;
  color:var(--silver-300);
  background:linear-gradient(180deg,transparent,rgba(8,18,43,.88));
}

/* ---------- 18 跳转链接 ---------- */
.skip-link{
  position:absolute;
  top:-70px;
  left:50%;
  z-index:120;
  padding:10px 20px;
  border-radius:0 0 10px 10px;
  background:var(--green-400);
  color:var(--blue-900);
  font-size:14px;
  font-weight:700;
  text-decoration:none;
  transform:translateX(-50%);
  transition:top .2s ease;
}
.skip-link:focus-visible{top:0}

/* ---------- 19 页头：居中刊头导航 ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:80;
  border-bottom:1px solid var(--line);
  background:rgba(8,18,43,.9);
  -webkit-backdrop-filter:blur(16px) saturate(140%);
  backdrop-filter:blur(16px) saturate(140%);
}

.masthead{
  position:relative;
  display:flex;
  flex-direction:column;
  align-items:center;
  width:100%;
  max-width:var(--wrap);
  margin-inline:auto;
  padding:20px var(--gutter) 14px;
}

.masthead__kicker{
  margin:0 0 8px;
  font-size:11px;
  letter-spacing:.34em;
  color:var(--silver-500);
  text-align:center;
}

.brand{
  display:inline-block;
  font-family:var(--font-display);
  font-weight:900;
  font-size:clamp(28px,5.2vw,46px);
  line-height:1.05;
  letter-spacing:-.02em;
  color:var(--ice-white);
  text-decoration:none;
}
.brand::after{
  content:"";
  display:block;
  height:3px;
  margin-top:9px;
  background:linear-gradient(90deg,transparent,var(--cyan-400) 16%,var(--green-400) 50%,var(--orange-500) 84%,transparent);
}

.masthead__tools{
  position:absolute;
  right:var(--gutter);
  top:34px;
}

.pill{
  display:inline-flex;
  align-items:center;
  gap:10px;
  padding:10px 17px;
  border:1px solid rgba(255,255,255,.28);
  border-radius:999px;
  background:linear-gradient(135deg,var(--orange-500),#FF9A4D);
  color:var(--blue-900);
  font-size:13px;
  font-weight:700;
  letter-spacing:.06em;
  text-decoration:none;
  box-shadow:0 10px 26px rgba(255,122,41,.28);
  transition:transform .2s ease,box-shadow .2s ease;
}
.pill:hover{transform:translateY(-2px);box-shadow:0 14px 32px rgba(255,122,41,.4)}
.pill__label{white-space:nowrap}
.pill__meta{
  font-family:var(--font-mono);
  font-size:11px;
  letter-spacing:.08em;
  opacity:.72;
}

.navtoggle{
  display:none;
  position:absolute;
  right:var(--gutter);
  top:34px;
  align-items:center;
  justify-content:center;
  gap:8px;
  min-width:44px;
  min-height:44px;
  padding:9px 12px;
  border:1px solid var(--line-strong);
  border-radius:4px;
  background:rgba(27,58,122,.55);
  color:var(--silver-100);
  font-size:12.5px;
  letter-spacing:.16em;
  cursor:pointer;
}
.navtoggle__bars{display:inline-flex;flex-direction:column;gap:4px;width:18px}
.navtoggle__bars i{
  display:block;
  height:2px;
  border-radius:2px;
  background:currentColor;
  transition:transform .2s ease,opacity .2s ease;
}
.navtoggle[aria-expanded="true"] .navtoggle__bars i:nth-child(1){transform:translateY(6px) rotate(45deg)}
.navtoggle[aria-expanded="true"] .navtoggle__bars i:nth-child(2){opacity:0}
.navtoggle[aria-expanded="true"] .navtoggle__bars i:nth-child(3){transform:translateY(-6px) rotate(-45deg)}

.mainnav{width:100%;margin-top:12px}
.mainnav__list{
  display:flex;
  flex-wrap:wrap;
  justify-content:center;
  gap:clamp(10px,2.4vw,34px);
  list-style:none;
}
.mainnav__link{
  position:relative;
  display:block;
  padding:8px 2px;
  color:var(--silver-300);
  font-size:14.5px;
  letter-spacing:.06em;
  text-decoration:none;
  transition:color .2s ease;
}
.mainnav__link::after{
  content:"";
  position:absolute;
  left:0;right:0;bottom:2px;
  height:2px;
  background:linear-gradient(90deg,var(--cyan-400),var(--green-400));
  transform:scaleX(0);
  transform-origin:center;
  transition:transform .25s ease;
}
.mainnav__link:hover{color:var(--ice-white)}
.mainnav__link:hover::after{transform:scaleX(1)}
.mainnav__link[aria-current="page"]{color:var(--green-400);font-weight:700}
.mainnav__link[aria-current="page"]::after{transform:scaleX(1);background:var(--green-400)}

.progress{
  position:absolute;
  left:0;bottom:-1px;
  width:100%;height:2px;
  transform:scaleX(0);
  transform-origin:left center;
  background:linear-gradient(90deg,var(--cyan-400),var(--green-400) 55%,var(--orange-500));
}

/* ---------- 20 页脚 ---------- */
.site-footer{
  position:relative;
  margin-top:clamp(40px,6vw,88px);
  border-top:1px solid var(--line);
  background:var(--blue-900);
  overflow:hidden;
}
.site-footer::before{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background:
    radial-gradient(720px 260px at 12% 0%,rgba(27,58,122,.62),transparent 68%),
    radial-gradient(560px 220px at 88% 6%,rgba(75,255,158,.09),transparent 70%);
}
.footer__inner{
  position:relative;
  z-index:1;
  padding-top:clamp(34px,5vw,62px);
  padding-bottom:34px;
}
.footer__brand{
  display:flex;
  flex-direction:column;
  gap:6px;
  padding-bottom:26px;
  border-bottom:1px dashed rgba(183,198,221,.2);
}
.footer__mark{
  font-family:var(--font-display);
  font-weight:900;
  font-size:clamp(22px,3.4vw,32px);
  letter-spacing:-.02em;
  color:var(--ice-white);
  text-decoration:none;
}
.footer__tag{margin:0;font-size:12px;letter-spacing:.22em;color:var(--silver-500)}
.footer__cols{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:28px 32px;
  padding:30px 0;
}
.footer__title{
  display:flex;
  align-items:baseline;
  gap:9px;
  margin:0 0 12px;
  font-size:12px;
  letter-spacing:.28em;
  color:var(--silver-300);
}
.footer__num{font-size:11px;letter-spacing:0;color:var(--cyan-400)}
.footer__list{display:flex;flex-direction:column;gap:9px;list-style:none}
.footer__link{
  color:var(--silver-100);
  font-size:14.5px;
  text-decoration:none;
  border-bottom:1px solid transparent;
  transition:color .2s ease,border-color .2s ease;
}
.footer__link:hover{color:var(--green-400);border-bottom-color:var(--green-400)}
.footer__meta{
  display:flex;
  flex-wrap:wrap;
  justify-content:space-between;
  gap:12px 24px;
  padding-top:22px;
  border-top:1px solid rgba(183,198,221,.16);
  font-size:12.5px;
  color:var(--silver-500);
}
.footer__contact{display:flex;flex-wrap:wrap;align-items:center;gap:7px 10px;margin:0}
.footer__contact-label{
  padding:0 9px;
  border-radius:999px;
  background:var(--silver-300);
  color:var(--blue-900);
  font-size:11px;
  letter-spacing:.14em;
}
.footer__dot{color:var(--blue-500)}
.footer__legal{margin:0}
@media (max-width:760px){
  .footer__cols{grid-template-columns:1fr 1fr}
}
@media (max-width:480px){
  .footer__cols{grid-template-columns:1fr}
}

/* ---------- 21 返回顶部 ---------- */
.backtop{
  position:fixed;
  right:clamp(14px,3vw,32px);
  bottom:clamp(14px,3vw,32px);
  z-index:70;
  display:inline-flex;
  align-items:center;
  gap:7px;
  padding:10px 15px;
  border:1px solid rgba(95,216,245,.4);
  border-radius:999px;
  background:rgba(16,34,76,.88);
  color:var(--silver-100);
  font-family:inherit;
  font-size:12px;
  letter-spacing:.16em;
  cursor:pointer;
  box-shadow:var(--shadow);
  -webkit-backdrop-filter:blur(10px);
  backdrop-filter:blur(10px);
  transition:transform .2s ease,color .2s ease,border-color .2s ease;
}
.backtop[hidden]{display:none}
.backtop:hover{transform:translateY(-3px);color:var(--green-400);border-color:var(--green-400)}
.backtop__arrow{font-size:14px;line-height:1}

/* ---------- 22 移入显现（JS 启用后才隐藏） ---------- */
.js-reveal [data-reveal]{
  opacity:0;
  transform:translateY(18px);
  transition:opacity .6s ease,transform .6s cubic-bezier(.2,.7,.3,1);
}
.js-reveal [data-reveal="in"]{opacity:1;transform:none}

/* ---------- 23 响应式：导航折叠 ---------- */
@media (max-width:900px){
  html{scroll-padding-top:120px}

  .masthead{
    display:grid;
    grid-template-columns:44px minmax(0,1fr) 44px;
    align-items:center;
    gap:6px 8px;
    padding:12px var(--gutter) 14px;
  }
  .masthead__kicker{
    grid-area:1 / 1 / 2 / 4;
    margin:0;
    font-size:10.5px;
    letter-spacing:.2em;
  }
  .brand{grid-area:2 / 1 / 3 / 4;justify-self:center;font-size:clamp(26px,8vw,34px)}
  .brand::after{margin-top:6px}
  .navtoggle{
    grid-area:2 / 3 / 3 / 4;
    justify-self:end;
    position:static;
  }
  .navtoggle__text{
    position:absolute;
    width:1px;height:1px;
    overflow:hidden;
    clip:rect(0 0 0 0);
    white-space:nowrap;
  }
  .mainnav{grid-area:3 / 1 / 4 / 4;display:none;width:100%;margin-top:4px}
  .mainnav[data-open]{display:block}
  .mainnav__list{
    flex-direction:column;
    align-items:stretch;
    gap:0;
    padding:6px 0 4px;
    border-top:1px dashed rgba(183,198,221,.24);
  }
  .mainnav__item{border-bottom:1px solid rgba(183,198,221,.1)}
  .mainnav__link{padding:12px 2px;font-size:15px}
  .mainnav__link::after{display:none}
  .mainnav__link[aria-current="page"]{padding-left:10px}
  .masthead__tools{
    position:static;
    grid-area:4 / 1 / 5 / 4;
    justify-self:center;
    margin-top:6px;
  }
}

/* ---------- 24 无障碍与动效偏好 ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  .js-reveal [data-reveal]{opacity:1 !important;transform:none !important}
  .pill:hover,.btn:hover,.backtop:hover{transform:none}
}