/* ============================================================
   B体育入口 · 共享样式 /assets/site.css
   炭黑 + 深墨绿基底，荧光青与电光橙强调，粗边框硬阴影
   ============================================================ */

/* ---------- 变量 ---------- */
:root{
  --ink:#0B1210;
  --ink-2:#10231C;
  --ink-3:#16332A;
  --paper:#E9E4D8;
  --paper-2:#F4F1E8;
  --cyan:#17E6C8;
  --orange:#FF7A1A;
  --red:#E23E57;
  --mute:#9FB3AC;
  --line:#3A4A44;
  --ink-mute-on-paper:#4A5A54;
  --cyan-on-paper:#0A7F6E;
  --rail-w:88px;
  --bar-h:58px;
  --shadow-hard:6px 6px 0 rgba(11,18,16,.8);
  --shadow-soft:4px 4px 0 rgba(11,18,16,.55);
  --dur-1:160ms;
  --dur-2:320ms;
  --dur-3:480ms;
  --ease:cubic-bezier(.2,.7,.2,1);
  --font-head:"Barlow Condensed","Oswald","PingFang SC","Noto Sans SC",system-ui,sans-serif;
  --font-body:"PingFang SC","Noto Sans SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-mono:ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono",monospace;
}

/* ---------- reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;
  background:var(--ink);
  color:var(--paper);
  font-family:var(--font-body);
  font-size:17px;
  line-height:1.85;
  padding-top:var(--bar-h);
  overflow-x:hidden;
}
body[data-nav-open="true"]{overflow:hidden}
img,svg,video{display:block;max-width:100%;height:auto}
h1,h2,h3,h4,h5{margin:0;font-family:var(--font-head);font-weight:300;letter-spacing:-.02em;line-height:1.08}
p{margin:0 0 1em}
ul,ol{margin:0;padding:0;list-style:none}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
a{color:inherit;text-decoration:none}
table{border-collapse:collapse;width:100%}
:focus-visible{outline:3px solid var(--orange);outline-offset:3px}

/* ---------- 通用排版 ---------- */
.mono{font-family:var(--font-mono);font-size:14px;letter-spacing:.08em;font-variant-numeric:tabular-nums}
.eyebrow{
  display:flex;align-items:center;gap:10px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.2em;
  color:var(--cyan);text-transform:uppercase;margin:0 0 14px;line-height:1.4;
}
.eyebrow::before{content:"";display:block;width:28px;height:2px;background:currentColor;flex:none}
.display-1{font-size:clamp(48px,9vw,128px);font-weight:200;line-height:.9;letter-spacing:-.03em;margin:0}
.display-2{font-size:clamp(32px,5.2vw,64px);font-weight:200;line-height:.98;letter-spacing:-.02em;margin:0}
.heading-3{font-size:clamp(20px,2.4vw,30px);font-weight:600;letter-spacing:0;line-height:1.25;margin:0}
.lede{font-size:clamp(17px,1.7vw,21px);line-height:1.7;color:var(--mute);max-width:62ch;margin:0}
.text-link{border-bottom:1px solid rgba(23,230,200,.5);transition:border-color var(--dur-1) var(--ease),color var(--dur-1) var(--ease)}
.text-link:hover{color:var(--cyan);border-bottom-color:var(--cyan)}
.visually-hidden{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}

/* ---------- 容器与章节 ---------- */
.container{width:100%;max-width:1280px;margin:0 auto;padding:0 20px;position:relative}
.container--narrow{max-width:820px}
@media (min-width:768px){.container{padding:0 32px}}
@media (min-width:1024px){.container{padding:0 48px}}

.section{position:relative;padding:64px 0}
.section--tight{padding:36px 0}
.section--deep{background:var(--ink-2)}
.section--paper{background:var(--paper);color:var(--ink)}
.section--paper .lede{color:var(--ink-mute-on-paper)}
.section--paper .eyebrow{color:var(--cyan-on-paper)}
.section--paper .mono{color:var(--ink-mute-on-paper)}
@media (min-width:1024px){.section{padding:96px 0}.section--tight{padding:48px 0}}

.section__head{
  display:flex;flex-wrap:wrap;gap:16px 32px;align-items:flex-end;justify-content:space-between;
  padding-bottom:16px;margin-bottom:32px;border-bottom:2px solid rgba(159,179,172,.25);
}
.section--paper .section__head{border-bottom-color:rgba(58,74,68,.35)}

/* ---------- 网格 ---------- */
.grid{display:grid;gap:24px;grid-template-columns:repeat(12,minmax(0,1fr))}
.grid > *{grid-column:1 / -1}
@media (min-width:900px){
  .grid--split > *{grid-column:span 6}
  .grid--side > *:first-child{grid-column:span 7}
  .grid--side > *:last-child{grid-column:span 5}
  .span-4{grid-column:span 4}
  .span-6{grid-column:span 6}
  .span-8{grid-column:span 8}
}

/* ---------- 按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:10px;
  padding:12px 22px;border:2px solid var(--paper);background:transparent;color:var(--paper);
  font-family:var(--font-head);font-size:16px;font-weight:600;letter-spacing:.08em;line-height:1.2;
  box-shadow:var(--shadow-soft);
  transition:transform var(--dur-1) var(--ease),box-shadow var(--dur-1) var(--ease),
             background-color var(--dur-1) var(--ease),color var(--dur-1) var(--ease),border-color var(--dur-1) var(--ease);
}
.btn:hover{transform:translate(-2px,-2px);box-shadow:var(--shadow-hard)}
.btn:active{transform:translate(0,0);box-shadow:2px 2px 0 rgba(11,18,16,.6)}
.btn--solid{background:var(--cyan);border-color:var(--cyan);color:var(--ink)}
.btn--ghost{background:transparent;border-color:var(--line);color:var(--paper)}
.btn--ghost:hover{border-color:var(--cyan);color:var(--cyan)}
.btn--warn{background:var(--orange);border-color:var(--orange);color:var(--ink)}
.btn--block{width:100%}

/* ---------- 页头与面包屑 ---------- */
.page-head{padding:40px 0 28px;position:relative}
.page-head__title{font-size:clamp(40px,7vw,96px);font-weight:200;line-height:.95;letter-spacing:-.03em;margin:0}
@media (min-width:1024px){.page-head{padding:56px 0 40px}}

.breadcrumb{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;
  color:var(--mute);padding:20px 0 0;
}
.breadcrumb__item{display:inline-flex;align-items:center;gap:8px}
.breadcrumb__item a{border-bottom:1px solid rgba(23,230,200,.4)}
.breadcrumb__item a:hover{color:var(--cyan)}
.breadcrumb__sep{color:var(--line)}

/* ---------- 侧栏轨道 / 移动抽屉 ---------- */
.site-header{position:relative;z-index:120}

.skip-link{
  position:fixed;top:8px;left:8px;z-index:200;
  padding:10px 16px;background:var(--cyan);color:var(--ink);
  font-family:var(--font-mono);font-size:13px;letter-spacing:.1em;
  border:2px solid var(--ink);box-shadow:var(--shadow-soft);
  transform:translateY(-220%);
  transition:transform var(--dur-1) var(--ease);
}
.skip-link:focus{transform:translateY(0)}

.scroll-progress{
  position:fixed;top:var(--bar-h);left:0;right:0;height:3px;z-index:140;
  background:rgba(58,74,68,.4);pointer-events:none;
}
.scroll-progress__bar{
  display:block;height:100%;width:100%;
  background:linear-gradient(90deg,var(--cyan),var(--orange));
  transform:scaleX(0);transform-origin:0 50%;
}

/* 移动端顶栏 */
.mobile-bar{
  position:fixed;top:0;left:0;right:0;height:var(--bar-h);z-index:130;
  display:flex;align-items:center;justify-content:space-between;gap:12px;
  padding:0 16px;background:var(--ink-2);border-bottom:2px solid var(--line);
}
.mobile-bar__brand{display:inline-flex;align-items:center;gap:10px}
.mobile-bar__mark{
  display:grid;place-items:center;width:30px;height:30px;
  border:2px solid var(--cyan);color:var(--cyan);
  font-family:var(--font-head);font-size:17px;font-weight:600;line-height:1;
  background:rgba(23,230,200,.08);
}
.mobile-bar__name{font-family:var(--font-head);font-size:20px;font-weight:600;letter-spacing:.04em}

.nav-toggle{
  display:inline-flex;align-items:center;gap:10px;padding:8px 12px;
  border:2px solid var(--line);background:var(--ink-3);color:var(--paper);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.12em;
  box-shadow:3px 3px 0 rgba(0,0,0,.5);
  transition:border-color var(--dur-1) var(--ease),color var(--dur-1) var(--ease);
}
.nav-toggle:hover{border-color:var(--cyan);color:var(--cyan)}
.nav-toggle__box{display:grid;gap:4px;width:18px}
.nav-toggle__bar{
  display:block;height:2px;width:100%;background:var(--cyan);
  transition:transform var(--dur-1) var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:first-child{transform:translateY(3px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:last-child{transform:translateY(-3px) rotate(-45deg)}
.nav-toggle__text{white-space:nowrap}

/* 抽屉形态（默认 / 移动端 / 矮屏桌面） */
.site-rail{
  position:fixed;top:0;left:0;bottom:0;z-index:135;
  width:min(92vw,340px);
  display:flex;flex-direction:column;gap:20px;
  padding:24px 20px 28px;overflow-y:auto;
  background:var(--ink-2);border-right:2px solid var(--line);
  transform:translateX(-102%);visibility:hidden;
  transition:transform var(--dur-2) var(--ease),visibility var(--dur-2) var(--ease);
}
.site-rail[data-open="true"]{transform:none;visibility:visible}

.rail-scrim{
  position:fixed;inset:0;z-index:128;background:rgba(11,18,16,.7);
  opacity:0;visibility:hidden;
  transition:opacity var(--dur-2) var(--ease),visibility var(--dur-2) var(--ease);
}
body[data-nav-open="true"] .rail-scrim{opacity:1;visibility:visible}

.site-rail__brand{display:flex;align-items:center;gap:12px}
.site-rail__mark{
  display:grid;place-items:center;width:40px;height:40px;flex:none;
  border:2px solid var(--cyan);color:var(--cyan);
  font-family:var(--font-head);font-size:23px;font-weight:600;line-height:1;
  background:rgba(23,230,200,.08);box-shadow:4px 4px 0 rgba(0,0,0,.5);
}
.site-rail__word{font-family:var(--font-head);font-size:22px;font-weight:600;letter-spacing:.06em}
.site-rail__tag{
  margin:0;font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;
  color:var(--cyan);text-transform:uppercase;
}

.site-nav{width:100%}
.site-nav__list{display:flex;flex-direction:column;list-style:none}
.site-nav__item{border-bottom:1px solid rgba(159,179,172,.18)}
.site-nav__item:first-child{border-top:1px solid rgba(159,179,172,.18)}
.site-nav__link{
  display:flex;align-items:center;gap:14px;padding:14px 8px;
  color:var(--paper);border-left:3px solid transparent;
  transition:background-color var(--dur-1) var(--ease),color var(--dur-1) var(--ease),border-color var(--dur-1) var(--ease);
}
.site-nav__num{font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;color:var(--mute);flex:none}
.site-nav__text{font-family:var(--font-head);font-size:19px;font-weight:500;letter-spacing:.06em}
.site-nav__link:hover{background:var(--ink-3);color:var(--cyan)}
.site-nav__link:hover .site-nav__num{color:var(--cyan)}
.site-nav__link[aria-current="page"]{
  color:var(--cyan);background:linear-gradient(90deg,rgba(23,230,200,.14),transparent);
  border-left-color:var(--cyan);
}
.site-nav__link[aria-current="page"] .site-nav__num{color:var(--orange)}

.site-rail__actions{display:grid;gap:10px;margin-top:auto}

/* 桌面轨道形态 */
@media (min-width:1024px) and (min-height:661px){
  body{padding-top:0;padding-left:var(--rail-w)}
  .mobile-bar{display:none}
  .rail-scrim{display:none}
  .scroll-progress{top:0;left:var(--rail-w)}

  .site-rail{
    width:var(--rail-w);right:auto;
    transform:none;visibility:visible;
    align-items:center;gap:14px;
    padding:14px 8px 16px;overflow:visible;
    transition:none;
  }
  .site-rail__brand{flex-direction:column;gap:10px;text-align:center}
  .site-rail__mark{width:44px;height:44px;font-size:26px}
  .site-rail__word{
    writing-mode:vertical-rl;
    font-family:var(--font-mono);font-size:12px;font-weight:400;
    letter-spacing:.22em;color:var(--mute);
  }
  .site-rail__tag{display:none}

  .site-nav{flex:1;min-height:0;overflow-y:auto;display:flex;align-items:center}
  .site-nav__list{width:100%}
  .site-nav__item{border:0}
  .site-nav__item:first-child{border-top:0}
  .site-nav__link{
    flex-direction:column;justify-content:center;gap:5px;
    padding:9px 2px;border-left:0;
    box-shadow:inset 3px 0 0 transparent;
  }
  .site-nav__num{font-size:10px}
  .site-nav__text{
    writing-mode:vertical-rl;
    font-size:clamp(12px,1.7vh,15px);letter-spacing:.14em;font-weight:500;
  }
  .site-nav__link[aria-current="page"]{
    background:linear-gradient(90deg,rgba(23,230,200,.16),transparent);
    box-shadow:inset 3px 0 0 var(--cyan);
  }
  .site-rail__actions{width:100%;gap:8px}
  .site-rail__actions .btn{font-size:13px;padding:9px 4px;letter-spacing:.08em;box-shadow:3px 3px 0 rgba(0,0,0,.5)}
}

/* ---------- 卡片 · 横向流 · 索引 · 标签 ---------- */
.card{
  position:relative;padding:22px;
  background:var(--ink-3);border:2px solid var(--line);box-shadow:var(--shadow-hard);
}
.section--paper .card{background:var(--paper-2);border-color:rgba(58,74,68,.5);box-shadow:6px 6px 0 rgba(58,74,68,.28)}
.card__num{display:block;font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;color:var(--cyan);margin-bottom:10px}
.section--paper .card__num{color:var(--cyan-on-paper)}
.card__title{font-family:var(--font-head);font-size:22px;font-weight:600;line-height:1.25;margin:0 0 8px}
.card__text{font-size:15px;line-height:1.75;color:var(--mute);margin:0}
.section--paper .card__text{color:var(--ink-mute-on-paper)}

.flow{
  display:flex;gap:16px;overflow-x:auto;scroll-snap-type:x mandatory;
  padding:4px 20px 18px;margin:0 -20px;
  scrollbar-color:var(--cyan) rgba(58,74,68,.3);
}
.flow__item{flex:0 0 80%;max-width:360px;scroll-snap-align:start}
@media (min-width:768px){.flow__item{flex-basis:46%}}
@media (min-width:1024px){.flow{padding-left:48px;padding-right:48px;margin:0 -48px}.flow__item{flex-basis:29%}}

.index-list{border-top:2px solid var(--line)}
.index-list__item{
  display:flex;align-items:baseline;gap:16px;
  padding:14px 0;border-bottom:1px solid rgba(159,179,172,.22);
}
.index-list__num{
  flex:none;min-width:48px;
  font-family:var(--font-mono);font-size:13px;letter-spacing:.08em;color:var(--cyan);
}
.index-list__link{display:block;transition:color var(--dur-1) var(--ease)}
.index-list__link:hover{color:var(--cyan)}

.chip{
  display:inline-flex;align-items:center;gap:8px;padding:7px 14px;
  border:2px solid var(--line);background:var(--ink-2);color:var(--mute);
  font-family:var(--font-mono);font-size:13px;letter-spacing:.06em;
  transition:background-color var(--dur-1) var(--ease),color var(--dur-1) var(--ease),border-color var(--dur-1) var(--ease);
}
.chip:hover{border-color:var(--cyan);color:var(--paper)}
.chip--active,.chip[aria-pressed="true"]{background:var(--cyan);border-color:var(--cyan);color:var(--ink)}

.tag{
  display:inline-block;padding:3px 8px;border:1px solid var(--line);
  font-family:var(--font-mono);font-size:11px;letter-spacing:.12em;color:var(--mute);
}
.tag--live{border-color:var(--orange);color:var(--orange)}
.tag--update{border-color:var(--cyan);color:var(--cyan)}

/* ---------- 旁注 · 图像容器 ---------- */
.note{
  padding:14px 18px;border-left:4px solid var(--red);
  background:rgba(226,62,87,.08);color:var(--mute);font-size:15px;line-height:1.75;
}
.note--ink{background:rgba(11,18,16,.07);color:var(--ink-mute-on-paper)}

.media-frame{
  position:relative;overflow:hidden;
  border:2px solid var(--line);background:var(--ink-3);box-shadow:var(--shadow-hard);
}
.media-frame__img{
  display:block;width:100%;aspect-ratio:4/5;object-fit:cover;
  background:linear-gradient(150deg,var(--ink-3),var(--ink) 70%);
  filter:saturate(.92) contrast(1.06);
}
.media-frame--wide .media-frame__img{aspect-ratio:16/9}
.media-frame__cap{
  position:absolute;left:0;right:0;bottom:0;
  padding:10px 14px;border-top:2px solid var(--line);
  background:rgba(11,18,16,.82);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--paper);
}
@media (min-width:768px){.media-frame__img{aspect-ratio:3/2}}
@media (min-width:768px){.media-frame:not(.media-frame--wide) .media-frame__img{aspect-ratio:4/5}}

/* ---------- 页脚 ---------- */
.site-footer{
  position:relative;overflow:hidden;
  margin-top:0;padding:56px 0 28px;
  background:var(--ink-2);border-top:2px solid var(--line);
}
.site-footer::before{
  content:"";position:absolute;inset:-24px;pointer-events:none;
  background-image:repeating-linear-gradient(-4deg,rgba(159,179,172,.07) 0 1px,transparent 1px 28px);
}
.site-footer .container{z-index:1}

.footer-grid{display:grid;gap:32px;grid-template-columns:1fr;position:relative}
@media (min-width:768px){.footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media (min-width:1024px){.footer-grid{grid-template-columns:1.7fr 1fr 1fr 1fr;gap:40px}}

.footer-brand__lockup{display:inline-flex;align-items:center;gap:12px}
.footer-brand__mark{
  display:grid;place-items:center;width:38px;height:38px;flex:none;
  border:2px solid var(--cyan);color:var(--cyan);
  font-family:var(--font-head);font-size:22px;font-weight:600;line-height:1;
  background:rgba(23,230,200,.08);box-shadow:4px 4px 0 rgba(0,0,0,.45);
}
.footer-brand__name{font-family:var(--font-head);font-size:24px;font-weight:600;letter-spacing:.05em}
.footer-brand__tag{
  margin:16px 0 10px;font-family:var(--font-mono);font-size:12px;
  letter-spacing:.16em;color:var(--cyan);text-transform:uppercase;
}
.footer-brand__line{max-width:40ch;margin:0 0 18px;font-size:15px;color:var(--mute);line-height:1.8}

.footer-contact{display:grid;gap:6px}
.footer-contact__line{margin:0;font-size:14px;line-height:1.7;color:var(--mute);word-break:break-word}
.footer-contact__line:first-child{color:var(--paper)}

.footer-col__title{
  margin:0 0 14px;padding-bottom:10px;border-bottom:2px solid var(--line);
  font-family:var(--font-mono);font-size:12px;font-weight:400;
  letter-spacing:.2em;text-transform:uppercase;color:var(--mute);
}
.footer-col__list{display:grid;gap:10px}
.footer-link{
  display:inline-block;font-size:15px;color:var(--paper);
  border-bottom:1px solid transparent;
  transition:color var(--dur-1) var(--ease),border-color var(--dur-1) var(--ease);
}
.footer-link:hover{color:var(--cyan);border-bottom-color:var(--cyan)}

.footer-bottom{
  display:flex;flex-wrap:wrap;gap:10px 24px;justify-content:space-between;
  margin-top:40px;padding-top:20px;border-top:1px solid rgba(159,179,172,.22);
  font-size:13px;color:var(--mute);
}
.footer-legal{margin:0;color:var(--paper)}
.footer-note{margin:0}

/* 返回顶部 */
.to-top{
  position:fixed;right:16px;bottom:20px;z-index:115;
  display:inline-flex;align-items:center;gap:8px;padding:10px 14px;
  border:2px solid var(--cyan);background:var(--ink-2);color:var(--cyan);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;
  box-shadow:4px 4px 0 rgba(0,0,0,.6);
  opacity:0;visibility:hidden;transform:translateY(10px);
  transition:opacity var(--dur-1) var(--ease),transform var(--dur-1) var(--ease),visibility var(--dur-1) var(--ease),background-color var(--dur-1) var(--ease),color var(--dur-1) var(--ease);
}
.to-top[data-visible="true"]{opacity:1;visibility:visible;transform:none}
.to-top:hover{background:var(--cyan);color:var(--ink)}
.to-top__arrow{font-size:15px;line-height:1}
@media (min-width:1024px){.to-top{right:28px;bottom:28px}}

/* ---------- 显现动效 ---------- */
.js [data-reveal]{
  opacity:0;transform:translateY(14px);
  transition:opacity var(--dur-2) var(--ease),transform var(--dur-2) var(--ease);
}
.js [data-reveal].is-in{opacity:1;transform:none}

/* ---------- 无障碍：减少动态 ---------- */
@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 [data-reveal]{opacity:1;transform:none}
  .btn:hover{transform:none}
  .site-rail{transition:none}
}