/* ============================================================
   悦博体育中心 /assets/site.css
   墨绿暗场 + 精密网格 + 单一信号锚点
   ============================================================ */

/* ---------- 1. reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
html.yb-no-scroll,html.yb-no-scroll body{overflow:hidden}
body{
  margin:0;
  background-color:#0B1512;
  background-image:
    radial-gradient(120% 70% at 78% -10%, rgba(240,182,90,.10), rgba(11,21,18,0) 58%),
    linear-gradient(180deg, rgba(18,33,28,.92) 0%, rgba(11,21,18,1) 46%),
    repeating-linear-gradient(90deg, rgba(201,242,78,.045) 0 1px, transparent 1px 96px),
    repeating-linear-gradient(0deg, rgba(201,242,78,.035) 0 1px, transparent 1px 96px);
  background-attachment:fixed;
  color:var(--mist-200);
  font-family:var(--font-body);
  font-size:16.5px;
  line-height:1.8;
  letter-spacing:.01em;
  overflow-x:hidden;
}
img,svg,video{max-width:100%;display:block}
button,input,select,textarea{font:inherit;color:inherit}
a{color:inherit;text-decoration:none}
h1,h2,h3,h4,p,figure,blockquote,dl,dd{margin:0}
ul,ol{margin:0;padding:0;list-style:none}
h1,h2,h3,h4{font-family:var(--font-title);font-weight:900;line-height:1.16;letter-spacing:-.015em;text-wrap:balance}
:focus-visible{outline:2px solid var(--lime-400);outline-offset:3px;border-radius:2px}

/* ---------- 2. tokens ---------- */
:root{
  --ink-900:#0B1512;
  --ink-800:#12211C;
  --graphite-700:#1D2B2B;
  --slate-500:#5C6E6C;
  --mist-200:#C7D4D0;
  --paper-050:#F3F6F4;
  --orange-500:#FF6A2B;
  --lime-400:#C9F24E;
  --amber-300:#F0B65A;

  --line:rgba(92,110,108,.30);
  --line-soft:rgba(92,110,108,.18);
  --line-strong:rgba(199,212,208,.22);
  --text-dim:rgba(199,212,208,.64);
  --text-faint:rgba(199,212,208,.44);

  --font-title:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-num:"IBM Plex Mono","JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;

  --shell:1440px;
  --gutter:clamp(18px,4vw,56px);
  --radius:2px;
  --header-h:104px;
  --stack:clamp(20px,3vw,40px);
}

/* ---------- 3. shell / 容器 ---------- */
.yb-shell{width:100%;max-width:var(--shell);margin:0 auto;padding:0 var(--gutter)}
.yb-main{display:block;min-height:60vh}
#main-content{scroll-margin-top:120px}
.yb-skip{
  position:absolute;left:var(--gutter);top:-120px;z-index:99;
  display:inline-flex;align-items:center;min-height:44px;padding:0 18px;
  background:var(--lime-400);color:#0B1512;
  font-family:var(--font-title);font-weight:900;font-size:14px;
  border-radius:var(--radius);transition:top .18s ease;
}
.yb-skip:focus{top:10px}

/* ---------- 4. 页头 ---------- */
.yb-header{
  position:sticky;top:0;z-index:60;
  background:#0B1512;
  border-bottom:1px solid var(--line);
}
.yb-progress{
  position:absolute;left:0;right:0;bottom:-1px;height:2px;
  background:rgba(92,110,108,.18);pointer-events:none;
}
.yb-progress__bar{
  display:block;height:100%;width:0;
  background:linear-gradient(90deg,var(--lime-400) 0%,var(--amber-300) 62%,var(--orange-500) 100%);
}
.yb-header__top{border-bottom:1px solid var(--line-soft)}
.yb-header__top-inner{
  display:flex;align-items:center;gap:16px 24px;flex-wrap:wrap;
  min-height:66px;padding:11px 0;
  transition:min-height .22s ease,padding .22s ease;
}
.yb-header[data-scrolled] .yb-header__top-inner{min-height:52px;padding:6px 0}
.yb-header__tools{
  display:flex;align-items:center;gap:14px;flex-wrap:wrap;
  margin-left:auto;
}
.yb-header__cta{flex:0 0 auto}
.yb-header__axis{
  margin-left:auto;
  font-family:var(--font-num);font-size:11.5px;letter-spacing:.16em;
  color:var(--text-faint);white-space:nowrap;
}

/* 品牌 */
.yb-brand{display:inline-flex;align-items:center;gap:12px;flex:0 0 auto}
.yb-brand__mark{
  position:relative;display:inline-grid;place-items:center;
  width:40px;height:40px;border:1px solid var(--line-strong);border-radius:var(--radius);
  font-family:var(--font-num);font-weight:700;font-size:12.5px;letter-spacing:.06em;
  color:var(--lime-400);background:rgba(29,43,43,.55);
}
.yb-brand__mark::after{
  content:"";position:absolute;right:-1px;bottom:-1px;width:6px;height:6px;background:var(--orange-500);
}
.yb-brand__text{display:block}
.yb-brand__name{
  display:block;font-family:var(--font-title);font-weight:900;
  font-size:17px;line-height:1.25;letter-spacing:.01em;color:var(--paper-050);
}
.yb-brand__tag{display:block;font-size:12px;line-height:1.5;color:var(--text-dim);letter-spacing:.06em}
.yb-brand--footer{margin-bottom:18px}

/* 赛季区间切换器 */
.yb-season{
  display:flex;align-items:center;gap:8px;
  padding:4px 10px;border:1px solid var(--line);border-radius:var(--radius);
  background:rgba(29,43,43,.52);
}
.yb-season__label{
  font-size:11px;letter-spacing:.2em;color:var(--text-faint);white-space:nowrap;
  padding-right:6px;border-right:1px solid var(--line-soft);
}
.yb-season__btn{
  appearance:none;background:none;border:0;border-bottom:2px solid transparent;
  min-height:36px;padding:6px 6px;cursor:pointer;
  font-family:var(--font-num);font-weight:700;font-size:13px;letter-spacing:.02em;
  color:var(--text-dim);
  transition:color .18s ease,border-color .18s ease;
}
.yb-season__btn:hover{color:var(--mist-200)}
.yb-season__btn[aria-pressed="true"]{color:var(--orange-500);border-bottom-color:var(--orange-500)}

/* 工具链接 */
.yb-utility{display:flex;align-items:center;gap:18px}
.yb-utility__item{display:block}
.yb-utility__link{
  display:inline-block;padding:8px 0;font-size:12.5px;letter-spacing:.04em;
  color:var(--text-dim);border-bottom:1px solid transparent;
  transition:color .18s ease,border-color .18s ease;
}
.yb-utility__link:hover{color:var(--mist-200);border-bottom-color:var(--slate-500)}
.yb-utility--stack{flex-direction:column;align-items:flex-start;gap:2px}

/* 通用按钮 */
.yb-btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  min-height:44px;padding:0 18px;border:1px solid transparent;border-radius:var(--radius);
  font-family:var(--font-title);font-weight:700;font-size:14px;letter-spacing:.02em;
  cursor:pointer;transition:background-color .18s ease,color .18s ease,border-color .18s ease;
}
.yb-btn--primary{background:var(--orange-500);color:#170A03}
.yb-btn--primary:hover{background:#FF8551}
.yb-btn--ghost{border-color:var(--line-strong);color:var(--mist-200);background:rgba(29,43,43,.4)}
.yb-btn--ghost:hover{border-color:var(--lime-400);color:var(--lime-400)}

/* 移动导航按钮 */
.yb-nav-toggle{
  display:none;align-items:center;gap:10px;
  min-height:44px;min-width:44px;padding:0 12px;
  background:rgba(29,43,43,.5);border:1px solid var(--line-strong);border-radius:var(--radius);
  color:var(--mist-200);cursor:pointer;
}
.yb-nav-toggle__bars{display:grid;gap:4px;width:18px}
.yb-nav-toggle__bar{display:block;height:1.5px;background:currentColor;transition:transform .2s ease,opacity .2s ease}
.yb-nav-toggle__label{font-family:var(--font-num);font-size:11.5px;letter-spacing:.18em}
.yb-nav-toggle[aria-expanded="true"]{border-color:var(--lime-400);color:var(--lime-400)}
.yb-nav-toggle[aria-expanded="true"] .yb-nav-toggle__bar:nth-child(1){transform:translateY(5.5px) rotate(45deg)}
.yb-nav-toggle[aria-expanded="true"] .yb-nav-toggle__bar:nth-child(2){opacity:0}
.yb-nav-toggle[aria-expanded="true"] .yb-nav-toggle__bar:nth-child(3){transform:translateY(-5.5px) rotate(-45deg)}

/* 下层栏目索引 */
.yb-header__bar{transition:padding .22s ease}
.yb-header__bar-inner{
  display:flex;align-items:center;gap:16px;
  min-height:48px;padding:2px 0;
  transition:min-height .22s ease;
}
.yb-header[data-scrolled] .yb-header__bar-inner{min-height:38px}
.yb-nav__list{display:flex;flex-wrap:wrap;gap:2px}
.yb-nav__link{
  display:inline-flex;align-items:center;gap:8px;
  min-height:44px;padding:0 15px;
  font-size:14.5px;font-weight:500;color:var(--mist-200);
  border-bottom:2px solid transparent;
  transition:background-color .18s ease,color .18s ease,border-color .18s ease;
}
.yb-nav__num{font-family:var(--font-num);font-size:11px;letter-spacing:.04em;color:var(--text-faint)}
.yb-nav__link:hover{background:rgba(29,43,43,.72);color:var(--paper-050)}
.yb-nav__link[aria-current="page"]{color:var(--paper-050);border-bottom-color:var(--orange-500)}
.yb-nav__link[aria-current="page"] .yb-nav__num{color:var(--orange-500)}

/* 抽屉 */
.yb-drawer{
  position:fixed;left:0;right:0;top:0;bottom:0;z-index:70;
  background:#09110F;overflow-y:auto;
  padding:calc(84px + env(safe-area-inset-top,0px)) 0 40px;
  visibility:hidden;opacity:0;transform:translateY(-10px);pointer-events:none;
  transition:opacity .2s ease,transform .2s ease,visibility .2s linear;
}
.yb-drawer[data-open]{visibility:visible;opacity:1;transform:none;pointer-events:auto}
.yb-drawer__inner{padding:0 var(--gutter);display:grid;gap:28px}
.yb-drawer__nav .yb-nav__list{flex-direction:column;gap:0}
.yb-drawer__nav .yb-nav__link{
  width:100%;justify-content:flex-start;padding:14px 0;
  border-bottom:1px solid var(--line-soft);font-size:17px;font-weight:700;
  font-family:var(--font-title);
}
.yb-drawer__nav .yb-nav__link[aria-current="page"]{border-bottom-color:var(--orange-500)}
.yb-drawer__block{display:grid;gap:10px}
.yb-drawer__title{
  font-family:var(--font-num);font-size:11px;letter-spacing:.2em;color:var(--text-faint);
}
.yb-drawer__seasons{flex-wrap:wrap;background:transparent;border-color:var(--line-soft)}
.yb-drawer__foot{display:grid;gap:14px;border-top:1px solid var(--line);padding-top:20px}
.yb-drawer__meta{
  font-family:var(--font-num);font-size:12.5px;line-height:1.9;
  color:var(--text-dim);word-break:break-all;
}

/* ---------- 5. 页脚 ---------- */
.yb-footer{
  position:relative;margin-top:clamp(48px,8vw,120px);
  background:#12211C;border-top:1px solid var(--line-strong);
}
.yb-footer::before{
  content:"";display:block;height:2px;
  background:linear-gradient(90deg,var(--orange-500) 0 140px,rgba(92,110,108,.35) 140px 100%);
}
.yb-footer__top{padding:clamp(34px,5.6vw,68px) 0 0}
.yb-footer__grid{
  display:grid;gap:30px 28px;
  grid-template-columns:minmax(0,1.7fr) repeat(4,minmax(0,1fr));
}
.yb-footer__brand{min-width:0}
.yb-footer__contact{display:grid;gap:6px;margin-bottom:16px}
.yb-footer__contact-item{
  font-family:var(--font-num);font-size:12.5px;letter-spacing:.02em;
  color:var(--text-dim);word-break:break-all;
}
.yb-footer__note{font-size:12.5px;line-height:1.7;color:var(--text-faint);max-width:52ch}
.yb-footer__col{min-width:0}
.yb-footer__title{
  font-family:var(--font-num);font-size:11.5px;font-weight:700;letter-spacing:.2em;
  color:var(--text-faint);border-top:1px solid var(--line-soft);
  padding-top:12px;margin-bottom:14px;
}
.yb-footer__links{display:grid;gap:2px}
.yb-footer__link{
  display:inline-block;padding:6px 0;font-size:14.5px;color:var(--mist-200);
  border-bottom:1px solid transparent;transition:color .18s ease,border-color .18s ease;
}
.yb-footer__link:hover{color:var(--lime-400);border-bottom-color:rgba(201,242,78,.5)}
.yb-footer__bottom{
  margin-top:clamp(28px,4vw,52px);padding:18px 0 30px;
  border-top:1px solid var(--line);
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:10px 24px;
}
.yb-footer__legal{font-size:12.5px;color:var(--text-dim)}
.yb-footer__stamp{font-family:var(--font-num);font-size:12px;letter-spacing:.08em;color:var(--text-faint)}

/* ---------- 6. 章节与叙事骨架 ---------- */
.yb-section{
  position:relative;
  padding:clamp(40px,7vw,96px) 0;
  border-top:1px solid var(--line-soft);
}
.yb-section::before{
  content:"";position:absolute;left:0;top:-1px;width:0;height:2px;
  background:var(--orange-500);transition:width .45s ease;
}
.yb-section.is-current::before{width:clamp(60px,14vw,180px)}
.yb-section__head{display:grid;gap:12px;margin-bottom:clamp(20px,3vw,36px)}
.yb-section__num{
  font-family:var(--font-num);font-size:12px;font-weight:700;letter-spacing:.2em;
  color:var(--text-faint);transition:color .3s ease;
}
.yb-section.is-current .yb-section__num{color:var(--lime-400)}
.yb-section__title{font-size:clamp(26px,3.4vw,40px)}
.yb-section__note{font-size:13px;color:var(--text-dim);max-width:48ch;line-height:1.75}
.yb-eyebrow{
  font-family:var(--font-num);font-size:11.5px;letter-spacing:.22em;
  color:var(--text-faint);text-transform:uppercase;
}
.yb-lede{font-size:clamp(17px,1.6vw,20px);line-height:1.85;color:var(--mist-200);max-width:60ch}
.yb-prose{max-width:70ch;font-size:16.5px;line-height:1.85;color:var(--mist-200)}
.yb-prose h2{font-size:clamp(22px,2.6vw,30px);margin:34px 0 12px}
.yb-prose h3{font-size:clamp(18px,2vw,22px);margin:26px 0 10px;color:var(--paper-050)}
.yb-prose p{margin:0 0 16px}
.yb-prose ul,.yb-prose ol{margin:0 0 18px;padding-left:1.2em;list-style:disc}
.yb-prose ol{list-style:decimal}
.yb-prose li{margin:6px 0;color:var(--text-dim)}
.yb-prose strong{color:var(--paper-050)}
.yb-divider{height:1px;border:0;background:var(--line);margin:clamp(24px,4vw,48px) 0}

/* ---------- 7. 栅格 ---------- */
.yb-grid{display:grid;gap:var(--stack)}
.yb-grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.yb-grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.yb-grid--rail{grid-template-columns:minmax(120px,180px) minmax(0,1fr);gap:clamp(20px,3.4vw,56px)}
.yb-rail{position:sticky;top:var(--header-h);align-self:start;display:grid;gap:14px}
.yb-rail__label{
  writing-mode:vertical-rl;
  font-family:var(--font-num);font-size:13px;letter-spacing:.18em;
  color:var(--text-dim);border-left:1px solid var(--line);padding-left:10px;
}
.yb-rail__ticks{display:grid;gap:10px;font-family:var(--font-num);font-size:11.5px;color:var(--text-faint)}

/* ---------- 8. 数据卡片流 ---------- */
.yb-stream-wrap{position:relative}
.yb-stream{
  display:flex;gap:16px;overflow-x:auto;overscroll-behavior-x:contain;
  scroll-snap-type:x mandatory;scroll-behavior:smooth;
  padding:4px 0 20px;
  scrollbar-color:var(--slate-500) transparent;scrollbar-width:thin;
}
.yb-stream:focus-visible{outline:2px solid var(--lime-400);outline-offset:4px}
.yb-stream > *{scroll-snap-align:start}
.yb-stream::-webkit-scrollbar{height:6px}
.yb-stream::-webkit-scrollbar-thumb{background:var(--slate-500)}
.yb-stream-nav{display:flex;gap:8px;justify-content:flex-end}
.yb-stream-nav__btn{
  width:44px;height:44px;display:inline-grid;place-items:center;
  background:rgba(29,43,43,.6);border:1px solid var(--line-strong);border-radius:var(--radius);
  color:var(--mist-200);cursor:pointer;font-family:var(--font-num);font-size:15px;
  transition:border-color .18s ease,color .18s ease;
}
.yb-stream-nav__btn:hover{border-color:var(--lime-400);color:var(--lime-400)}
.yb-card{
  flex:0 0 clamp(240px,26vw,320px);min-width:0;
  display:grid;gap:10px;align-content:start;
  padding:20px;background:var(--graphite-700);
  border:1px solid var(--line);border-radius:var(--radius);
  transition:border-color .18s ease,background-color .18s ease;
}
.yb-card:hover{border-color:var(--line-strong);background:#223232}
.yb-card__code{font-family:var(--font-num);font-size:11.5px;letter-spacing:.14em;color:var(--lime-400)}
.yb-card__title{font-family:var(--font-title);font-weight:900;font-size:18px;line-height:1.32}
.yb-card__value{font-family:var(--font-num);font-weight:700;font-size:clamp(38px,5.4vw,64px);line-height:1;color:var(--paper-050)}
.yb-card__meta{font-size:12.5px;line-height:1.7;color:var(--text-dim)}
.yb-card[hidden]{display:none}

/* 超大指标 */
.yb-metric{
  font-family:var(--font-num);font-weight:700;letter-spacing:-.02em;
  font-size:clamp(48px,9vw,132px);line-height:.94;
  color:var(--paper-050);
  text-shadow:0 0 46px rgba(240,182,90,.20);
}
.yb-metric__unit{font-size:.24em;letter-spacing:.06em;color:var(--amber-300);margin-left:.3em}

/* ---------- 9. 图例 / 标记 / 面板 ---------- */
.yb-legend{display:flex;flex-wrap:wrap;gap:10px 22px}
.yb-legend__item{display:inline-flex;align-items:center;gap:8px;font-size:12.5px;color:var(--text-dim)}
.yb-legend__swatch{width:10px;height:10px;border-radius:var(--radius);background:var(--lime-400);flex:0 0 auto}
.yb-legend__swatch--orange{background:var(--orange-500)}
.yb-legend__swatch--amber{background:var(--amber-300)}
.yb-legend__swatch--slate{background:var(--slate-500)}
.yb-tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:3px 8px;border:1px solid var(--line-strong);border-radius:var(--radius);
  font-family:var(--font-num);font-size:11.5px;letter-spacing:.1em;color:var(--mist-200);
}
.yb-tag--lime{border-color:rgba(201,242,78,.5);color:var(--lime-400)}
.yb-tag--orange{border-color:rgba(255,106,43,.5);color:var(--orange-500)}
.yb-panel{
  padding:clamp(18px,2.4vw,28px);
  background:var(--ink-800);border:1px solid var(--line);border-radius:var(--radius);
}
.yb-panel--graphite{background:var(--graphite-700)}
.yb-invert{background:var(--paper-050);color:#0B1512}
.yb-invert .yb-section__note,.yb-invert .yb-prose p{color:rgba(11,21,18,.7)}
.yb-num{font-family:var(--font-num);font-weight:700;letter-spacing:.02em}

/* ---------- 10. 表格 / 折叠 / 面包屑 ---------- */
.yb-table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:var(--radius)}
.yb-table{width:100%;border-collapse:collapse;font-size:14px;min-width:520px}
.yb-table th,.yb-table td{padding:12px 14px;text-align:left;border-bottom:1px solid var(--line-soft)}
.yb-table thead th{
  font-family:var(--font-num);font-size:11.5px;font-weight:700;letter-spacing:.14em;
  color:var(--text-faint);background:rgba(29,43,43,.7);
}
.yb-table tbody tr:last-child td{border-bottom:0}
.yb-table tbody tr:hover td{background:rgba(29,43,43,.55)}

.yb-fold{border-top:1px solid var(--line)}
.yb-fold:last-child{border-bottom:1px solid var(--line)}
.yb-fold__btn{
  width:100%;display:flex;align-items:center;justify-content:space-between;gap:16px;
  min-height:52px;padding:16px 0;background:none;border:0;cursor:pointer;
  font-family:var(--font-title);font-weight:700;font-size:16px;text-align:left;
  color:var(--mist-200);transition:color .18s ease;
}
.yb-fold__btn:hover{color:var(--paper-050)}
.yb-fold__sign{
  flex:0 0 auto;font-family:var(--font-num);font-size:14px;color:var(--orange-500);
  transition:transform .2s ease;
}
.yb-fold__btn[aria-expanded="true"] .yb-fold__sign{transform:rotate(45deg)}
.yb-fold__panel{padding:0 0 20px;font-size:15px;line-height:1.8;color:var(--text-dim);max-width:72ch}
.yb-fold__panel[hidden]{display:none}

.yb-crumbs{display:flex;flex-wrap:wrap;gap:8px;font-family:var(--font-num);font-size:12px;letter-spacing:.08em;color:var(--text-faint)}
.yb-crumbs__item{display:inline-flex;gap:8px;align-items:center}
.yb-crumbs__item a{color:var(--text-dim);transition:color .18s ease}
.yb-crumbs__item a:hover{color:var(--lime-400)}
.yb-crumbs__sep{color:var(--text-faint)}

/* ---------- 11. 图片容器 ---------- */
.yb-media{
  position:relative;display:block;width:100%;overflow:hidden;
  background:var(--graphite-700);
  border:1px solid var(--line);border-radius:var(--radius);
  aspect-ratio:16 / 9;
}
.yb-media > img{width:100%;height:100%;object-fit:cover}
.yb-media--wide{aspect-ratio:21 / 9}
.yb-media--tall{aspect-ratio:4 / 5}
.yb-media--square{aspect-ratio:1 / 1}
.yb-media--grid::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background-image:
    repeating-linear-gradient(90deg,rgba(201,242,78,.10) 0 1px,transparent 1px 25%),
    linear-gradient(180deg,rgba(11,21,18,0) 45%,rgba(11,21,18,.65) 100%);
}
.yb-media__caption{display:block;margin-top:8px;font-size:12px;line-height:1.7;color:var(--text-faint)}
.yb-media-row{display:grid;gap:18px;grid-template-columns:repeat(auto-fit,minmax(240px,1fr))}

/* ---------- 12. 显现动效 ---------- */
[data-reveal]{opacity:0;transform:translateY(14px);transition:opacity .5s ease,transform .5s ease}
[data-reveal].is-in{opacity:1;transform:none}

/* ---------- 13. 响应式 ---------- */
@media (max-width:1280px){
  .yb-utility{display:none}
  .yb-footer__grid{grid-template-columns:minmax(0,1.5fr) repeat(4,minmax(0,1fr))}
}
@media (max-width:1080px){
  .yb-footer__grid{grid-template-columns:minmax(0,1fr) repeat(2,minmax(0,1fr))}
  .yb-footer__brand{grid-column:1 / -1}
}
@media (max-width:960px){
  :root{--header-h:88px}
  .yb-header__bar{display:none}
  .yb-nav-toggle{display:inline-flex}
  .yb-header__top-inner{flex-wrap:nowrap;gap:12px}
  .yb-header__tools{margin-left:auto}
  .yb-header__tools .yb-season,.yb-header__tools .yb-utility{display:none}
  .yb-grid--rail{grid-template-columns:minmax(0,1fr)}
  .yb-rail{position:static}
  .yb-rail__label{writing-mode:horizontal-tb;border-left:0;border-top:1px solid var(--line);padding:10px 0 0}
  .yb-grid--2,.yb-grid--3{grid-template-columns:minmax(0,1fr)}
}
@media (max-width:640px){
  body{font-size:16px}
  .yb-brand__tag{display:none}
  .yb-header__cta{display:none}
  .yb-footer__grid{grid-template-columns:minmax(0,1fr);gap:26px}
  .yb-card{flex:0 0 min(78vw,300px)}
  .yb-stream-nav{justify-content:flex-start}
}

/* ---------- 14. 可访问性与动效降级 ---------- */
@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]{opacity:1;transform:none}
  .yb-stream{scroll-behavior:auto}
  .yb-section::before{transition:none}
}