/* =============================================================
   OB体育入口 · /assets/site.css
   共享外壳：刊头导航、页脚、按钮、网格、图文容器、返回顶部
   ============================================================= */

/* ---------- 1. 设计变量 ---------- */
:root{
  --ink:#071A16;
  --ink-2:#0D2B24;
  --ink-3:#123329;
  --cyan:#38F2D0;
  --cyan-soft:#8CFFE9;
  --snow:#F2F7F4;
  --mist:#9FB8AF;
  --ochre:#B86B3C;
  --flag-red:#D94A3D;
  --flag-yellow:#E8B23A;
  --flag-blue:#3A7BD5;
  --flag-green:#3FAE6A;
  --gold:#FFD166;

  --line:rgba(56,242,208,.26);
  --line-soft:rgba(242,247,244,.12);
  --line-dash:rgba(159,184,175,.24);

  --font-display:"Noto Sans SC","Source Han Sans SC","PingFang SC","Arial Narrow",sans-serif;
  --font-body:"Noto Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
  --font-mono:"DIN Alternate","Roboto Mono","IBM Plex Mono",ui-monospace,monospace;

  --max:1240px;
  --gutter:clamp(16px,4vw,40px);
  --shadow-hard:8px 8px 0 rgba(56,242,208,.16);
  --shadow-ink:6px 6px 0 rgba(0,0,0,.55);
  --ease:cubic-bezier(.22,.61,.36,1);
}

/* ---------- 2. Reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;text-size-adjust:100%}
@media (prefers-reduced-motion:no-preference){
  html{scroll-behavior:smooth}
}
body{
  margin:0;
  background-color:var(--ink);
  background-image:
    radial-gradient(1200px 620px at 12% -8%,rgba(56,242,208,.09),transparent 62%),
    radial-gradient(900px 520px at 108% 4%,rgba(58,123,213,.12),transparent 58%);
  background-repeat:no-repeat;
  color:var(--snow);
  font-family:var(--font-body);
  font-size:17px;
  font-weight:400;
  line-height:1.8;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
h1,h2,h3,h4,h5,h6,p,figure,blockquote,dl,dd{margin:0}
ul,ol{margin:0;padding:0;list-style:none}
img,svg,video{display:block;max-width:100%;height:auto}
a{color:var(--cyan-soft);text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:3px}
button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer}
:focus-visible{outline:2px solid var(--cyan);outline-offset:3px}
::selection{background:var(--cyan);color:var(--ink)}

/* ---------- 3. 中文排版 ---------- */
h1,h2,h3,h4,h5,h6{
  font-family:var(--font-display);
  font-weight:900;
  line-height:1.08;
  letter-spacing:-.02em;
  color:var(--snow);
  margin-bottom:.6em;
}
h1{font-size:clamp(2.6rem,7.2vw,4.8rem);line-height:.95;letter-spacing:-.045em}
h2{font-size:clamp(1.75rem,4vw,2.9rem)}
h3{font-size:clamp(1.25rem,2.4vw,1.65rem)}
p{max-width:66ch}
strong{font-weight:700;color:var(--cyan-soft)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}

/* ---------- 4. 通用骨架 ---------- */
.container{width:100%;max-width:var(--max);margin-inline:auto;padding-inline:var(--gutter)}
.container--narrow{max-width:840px}
.visually-hidden{
  position:absolute;width:1px;height:1px;margin:-1px;padding:0;
  overflow:hidden;clip:rect(0 0 0 0);clip-path:inset(50%);white-space:nowrap;border:0;
}
.skip-link{
  position:fixed;top:-120px;left:var(--gutter);z-index:200;
  display:inline-flex;align-items:center;min-height:44px;
  padding:10px 20px;
  background:var(--cyan);color:var(--ink);
  font-size:14px;font-weight:700;letter-spacing:.08em;
  text-decoration:none;
  transition:top .18s var(--ease);
}
.skip-link:focus{top:12px}

.section{padding-block:clamp(44px,7vw,96px);border-top:1px solid var(--line-soft)}
.section:first-of-type{border-top:0}
.section__head{display:flex;flex-direction:column;gap:10px;margin-bottom:clamp(22px,3.4vw,40px)}

.eyebrow{
  display:inline-flex;align-items:center;gap:.7em;
  font-family:var(--font-mono);font-size:12px;font-weight:500;
  letter-spacing:.3em;text-transform:uppercase;color:var(--cyan);
}
.eyebrow::before{
  content:"";flex:0 0 auto;width:10px;height:10px;
  background:var(--cyan);transform:rotate(0deg);
}
.display{
  font-family:var(--font-display);font-weight:900;
  font-size:clamp(2.8rem,8vw,7rem);
  line-height:.92;letter-spacing:-.04em;color:var(--snow);
}
.lede{
  font-size:clamp(1.02rem,1.5vw,1.22rem);
  line-height:1.75;color:var(--snow);max-width:54ch;
}
.chapter-mark{
  display:inline-block;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.32em;
  color:var(--ochre);
  writing-mode:vertical-rl;text-orientation:mixed;
}
.rule{height:2px;border:0;margin:0;background:linear-gradient(90deg,var(--cyan),rgba(56,242,208,0))}

/* ---------- 5. 按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.5em;
  min-height:44px;padding:10px 20px;
  font-family:var(--font-body);font-size:15px;font-weight:700;letter-spacing:.06em;
  text-decoration:none;border:2px solid transparent;
  transition:transform .18s var(--ease),box-shadow .18s var(--ease),
             background-color .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease);
}
.btn--anchor{
  background:var(--cyan);border-color:var(--cyan);color:var(--ink);
  box-shadow:4px 4px 0 rgba(56,242,208,.18);
}
.btn--anchor:hover{background:var(--cyan-soft);border-color:var(--cyan-soft);transform:translate(-2px,-2px);box-shadow:7px 7px 0 rgba(56,242,208,.24)}
.btn--anchor:active{transform:translate(0,0);box-shadow:2px 2px 0 rgba(56,242,208,.22)}
.btn--ghost{background:transparent;border-color:rgba(242,247,244,.34);color:var(--snow)}
.btn--ghost:hover{border-color:var(--cyan);color:var(--cyan)}

/* ---------- 6. 刊头 ---------- */
.site-header{
  position:sticky;top:0;z-index:60;
  background:var(--ink);
  border-bottom:1px solid var(--line);
  box-shadow:0 10px 30px rgba(0,0,0,.45);
}
.masthead{
  position:relative;
  width:100%;max-width:var(--max);margin-inline:auto;
  padding:clamp(12px,2vw,20px) var(--gutter) clamp(10px,1.6vw,16px);
  display:grid;grid-template-columns:minmax(0,1fr) auto minmax(0,1fr);
  align-items:center;gap:10px 20px;
  background-image:
    linear-gradient(rgba(56,242,208,.045) 1px,transparent 1px);
  background-size:100% 22px;background-position:0 6px;
}
.masthead__meta{display:flex;align-items:center;gap:12px;min-width:0}
.masthead__meta--left{justify-content:flex-start}
.masthead__meta--right{justify-content:flex-end}
.masthead__coord{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;color:var(--mist);
  border-left:2px solid var(--ochre);padding-left:10px;white-space:nowrap;
}
.masthead__brand{
  display:flex;flex-direction:column;align-items:center;gap:4px;
  text-decoration:none;color:var(--snow);text-align:center;
}
.masthead__wordmark{
  font-family:var(--font-display);font-weight:900;
  font-size:clamp(1.4rem,2.6vw,2.05rem);line-height:1;letter-spacing:-.03em;
  transition:color .18s var(--ease);
}
.masthead__brand:hover .masthead__wordmark{color:var(--cyan)}
.masthead__tagline{
  font-size:11px;letter-spacing:.3em;color:var(--mist);white-space:nowrap;
}
.masthead__version{
  font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--cyan);
  border:1px solid var(--line);padding:3px 8px;
}

/* 进度轨 */
.site-header__progress{
  position:absolute;left:0;right:0;bottom:-1px;height:3px;
  background:rgba(56,242,208,.12);pointer-events:none;
}
.site-header__progress-bar{
  display:block;width:100%;height:100%;
  background:linear-gradient(90deg,var(--cyan),var(--flag-yellow));
  transform:scaleX(0);transform-origin:left center;
}

/* 移动目录按钮 */
.nav-toggle{
  display:none;align-items:center;gap:8px;
  min-height:44px;padding:8px 14px;
  border:2px solid var(--line);background:var(--ink-2);color:var(--snow);
  font-size:13px;letter-spacing:.16em;
  transition:border-color .18s var(--ease),color .18s var(--ease);
}
.nav-toggle:hover{border-color:var(--cyan);color:var(--cyan)}
.nav-toggle__bars{display:inline-flex;flex-direction:column;justify-content:center;gap:4px;width:18px}
.nav-toggle__bars span{display:block;height:2px;background:var(--cyan);transition:transform .2s var(--ease),opacity .2s 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)}

/* ---------- 7. 主导航 ---------- */
.site-nav{
  display:block;
  border-top:1px solid var(--line-soft);
  background:linear-gradient(180deg,rgba(13,43,36,.9),rgba(7,26,22,.9));
}
.site-nav__list{
  max-width:var(--max);margin-inline:auto;padding:0 var(--gutter);
  display:flex;flex-wrap:wrap;justify-content:center;align-items:center;gap:0 6px;
  counter-reset:navidx;
}
.site-nav__item{counter-increment:navidx;min-width:0}
.site-nav__link{
  position:relative;
  display:inline-flex;align-items:center;gap:.6em;
  min-height:46px;padding:0 14px;
  color:var(--snow);text-decoration:none;
  font-size:15px;letter-spacing:.14em;white-space:nowrap;
  transition:color .18s var(--ease);
}
.site-nav__link::before{
  content:counter(navidx,decimal-leading-zero);
  font-family:var(--font-mono);font-size:11px;letter-spacing:.04em;
  color:var(--ochre);
}
.site-nav__link::after{
  content:"";position:absolute;left:14px;right:14px;bottom:9px;height:2px;
  background:var(--cyan);
  transform:scaleX(0);transform-origin:left center;
  transition:transform .22s var(--ease);
}
.site-nav__link:hover{color:var(--cyan)}
.site-nav__link:hover::after,
.site-nav__link:focus-visible::after{transform:scaleX(1)}
.site-nav__link[aria-current="page"]{color:var(--cyan)}
.site-nav__link[aria-current="page"]::before{color:var(--cyan)}
.site-nav__link[aria-current="page"]::after{transform:scaleX(1);background:var(--cyan)}

/* ---------- 8. 页脚 ---------- */
.site-footer{
  margin-top:clamp(44px,7vw,96px);
  background:var(--ink);
  border-top:2px solid var(--line);
  position:relative;
}
.site-footer__inner{
  max-width:var(--max);margin-inline:auto;
  padding:clamp(30px,5vw,56px) var(--gutter) clamp(18px,3vw,28px);
}
.site-footer__flags{display:flex;gap:6px;margin-bottom:clamp(22px,3.6vw,36px)}
.site-footer__flag{flex:1 1 0;height:5px;background:var(--mist)}
.site-footer__flag:nth-child(1){background:var(--flag-blue)}
.site-footer__flag:nth-child(2){background:var(--snow)}
.site-footer__flag:nth-child(3){background:var(--flag-red)}
.site-footer__flag:nth-child(4){background:var(--flag-green)}
.site-footer__flag:nth-child(5){background:var(--flag-yellow)}

.site-footer__grid{
  display:grid;
  grid-template-columns:minmax(0,1.5fr) repeat(2,minmax(0,1fr)) minmax(0,1.25fr);
  gap:clamp(22px,4vw,40px);
  align-items:start;
}
.site-footer__identity{min-width:0}
.site-footer__brand{
  font-family:var(--font-display);font-weight:900;
  font-size:clamp(1.5rem,3vw,2rem);line-height:1.1;letter-spacing:-.02em;
  margin-bottom:.45em;
}
.site-footer__summary{color:var(--mist);font-size:15px;line-height:1.8;max-width:34ch;margin-bottom:1.2em}
.site-footer__col{min-width:0}
.site-footer__col-title,
.site-footer__contact-title{
  font-family:var(--font-mono);font-size:12px;font-weight:500;
  letter-spacing:.28em;color:var(--ochre);
  line-height:1.6;margin-bottom:1em;
}
.site-footer__list{display:flex;flex-direction:column;gap:2px}
.site-footer__link{
  display:inline-flex;align-items:center;gap:.5em;
  min-height:40px;color:var(--snow);font-size:15px;letter-spacing:.04em;
  text-decoration:none;
  transition:color .18s var(--ease);
}
.site-footer__link::before{
  content:"";width:0;height:2px;background:var(--cyan);
  transition:width .18s var(--ease);
}
.site-footer__link:hover{color:var(--cyan)}
.site-footer__link:hover::before{width:12px}
.site-footer__contact{min-width:0}
.site-footer__contact-list{display:flex;flex-direction:column;gap:10px;margin-bottom:1em}
.site-footer__contact-item{display:flex;gap:10px;font-size:14px;line-height:1.65;color:var(--snow)}
.site-footer__contact-key{
  flex:0 0 auto;align-self:flex-start;margin-top:3px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;color:var(--cyan);
  border:1px solid var(--line);padding:1px 6px;
}
.site-footer__contact-value{min-width:0;overflow-wrap:anywhere}
.site-footer__note{font-size:12px;line-height:1.7;color:var(--mist)}
.site-footer__bottom{
  margin-top:clamp(26px,4vw,44px);padding-top:16px;
  border-top:1px solid var(--line-soft);
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;
  gap:10px 24px;
  font-size:12px;letter-spacing:.08em;color:var(--mist);
}
.site-footer__legal{font-family:var(--font-mono);color:var(--mist)}
.site-footer__legal-links{display:flex;flex-wrap:wrap;gap:0 18px}
.site-footer__legal-link{
  display:inline-flex;align-items:center;min-height:36px;
  color:var(--mist);text-decoration:none;
  transition:color .18s var(--ease);
}
.site-footer__legal-link:hover{color:var(--cyan)}
.site-footer__copyright{color:var(--mist)}

/* ---------- 9. 网格与卡片 ---------- */
.grid{display:grid;gap:clamp(16px,2.4vw,28px)}
.grid--split{grid-template-columns:repeat(2,minmax(0,1fr))}
.card{
  position:relative;
  background:var(--ink-2);border:2px solid var(--line-soft);
  padding:clamp(18px,3vw,28px);
  box-shadow:var(--shadow-ink);
}
.card--anchor{border-color:var(--cyan);box-shadow:var(--shadow-hard)}
.panel{
  position:relative;
  padding:clamp(16px,2.6vw,24px) clamp(16px,2.6vw,24px);
  border-left:4px solid var(--cyan);
  background:rgba(13,43,36,.7);
}

/* ---------- 10. 标签 ---------- */
.badge{
  display:inline-flex;align-items:center;gap:.45em;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.16em;
  padding:4px 10px;border:1px solid var(--line);color:var(--cyan);
  text-transform:uppercase;white-space:nowrap;
}
.tag{
  display:inline-flex;align-items:center;gap:.4em;
  font-size:12px;letter-spacing:.12em;line-height:1.4;
  padding:3px 9px;border:1px solid var(--line-dash);color:var(--mist);
  white-space:nowrap;
}
.tag--ochre{color:var(--ochre);border-color:rgba(184,107,60,.55)}
.tag--red{color:var(--flag-red);border-color:rgba(217,74,61,.55)}
.tag--green{color:var(--flag-green);border-color:rgba(63,174,106,.55)}
.tag--gold{color:var(--gold);border-color:rgba(255,209,102,.55)}

/* ---------- 11. 面包屑 ---------- */
.breadcrumb{margin-bottom:clamp(16px,2.4vw,26px)}
.breadcrumb__list{
  display:flex;flex-wrap:wrap;align-items:center;gap:.4em;
  font-size:13px;letter-spacing:.08em;color:var(--mist);
}
.breadcrumb__item{display:inline-flex;align-items:center;gap:.4em;min-width:0}
.breadcrumb__item + .breadcrumb__item::before{content:"／";color:var(--ochre)}
.breadcrumb__link{color:var(--mist);text-decoration:none}
.breadcrumb__link:hover{color:var(--cyan)}

/* ---------- 12. 图片容器 ---------- */
.media{
  position:relative;margin:0;
  border:2px solid var(--line-soft);
  background:var(--ink-2);
  overflow:hidden;
}
.media__frame{
  position:relative;display:block;width:100%;
  aspect-ratio:16 / 9;
  background:
    linear-gradient(158deg,var(--ink-3) 0%,var(--ink) 58%,rgba(58,123,213,.18) 100%);
}
.media__frame > img,
.media__frame > picture,
.media__frame > picture > img{
  width:100%;height:100%;object-fit:cover;
}
.media__frame > img,
.media__frame > picture > img{filter:saturate(.94) contrast(1.06)}
.media--wide .media__frame{aspect-ratio:21 / 9}
.media--tall .media__frame{aspect-ratio:3 / 4}
.media--square .media__frame{aspect-ratio:1 / 1}
.media__caption{
  padding:10px 14px;border-top:1px solid var(--line-soft);
  font-size:12px;letter-spacing:.1em;color:var(--mist);line-height:1.7;
}

/* ---------- 13. 返回顶部（脚本注入） ---------- */
.to-top{
  position:fixed;right:clamp(12px,2.4vw,26px);bottom:clamp(12px,2.4vw,26px);z-index:80;
  display:inline-flex;align-items:center;gap:6px;
  min-height:44px;min-width:44px;padding:0 14px;
  background:var(--ink-2);color:var(--cyan);
  border:2px solid var(--line);
  box-shadow:var(--shadow-ink);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.16em;
  opacity:0;transform:translateY(12px);pointer-events:none;
  transition:opacity .22s var(--ease),transform .22s var(--ease),
             border-color .18s var(--ease),background-color .18s var(--ease);
}
.to-top[data-visible="true"]{opacity:1;transform:none;pointer-events:auto}
.to-top:hover{border-color:var(--cyan);background:var(--ink-3)}
.to-top__arrow{font-size:15px;line-height:1}

/* ---------- 14. 平板 ---------- */
@media (max-width:1024px){
  .site-footer__grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .site-footer__identity{grid-column:1 / -1}
}

/* ---------- 15. 移动端 ---------- */
@media (max-width:900px){
  .masthead{
    display:flex;align-items:center;justify-content:space-between;gap:12px;
    padding:12px var(--gutter);
    background-image:none;
  }
  .masthead__meta--left,
  .masthead__meta--right{display:none}
  .masthead__brand{flex:1 1 auto;min-width:0;align-items:flex-start;text-align:left}
  .masthead__wordmark{font-size:clamp(1.25rem,5vw,1.6rem)}
  .masthead__tagline{font-size:10px;letter-spacing:.24em}
  .nav-toggle{display:inline-flex;flex:0 0 auto}

  .site-nav{
    display:none;
    border-top:1px solid var(--line-soft);
    background:var(--ink-2);
    box-shadow:0 18px 36px rgba(0,0,0,.5);
  }
  .site-nav[data-open="true"]{display:block}
  .site-nav__list{
    flex-direction:column;flex-wrap:nowrap;justify-content:flex-start;align-items:stretch;
    padding:6px var(--gutter) 18px;gap:0;
  }
  .site-nav__item{width:100%}
  .site-nav__link{
    width:100%;min-height:54px;justify-content:flex-start;gap:14px;
    padding:0 4px;font-size:17px;letter-spacing:.06em;
    border-bottom:1px solid rgba(242,247,244,.08);
  }
  .site-nav__link::after{display:none}
  .site-nav__link[aria-current="page"]{background:rgba(56,242,208,.07)}

  .grid--split{grid-template-columns:1fr}
  .media--wide .media__frame{aspect-ratio:16 / 9}
}

@media (max-width:600px){
  body{font-size:16px}
  .site-footer__grid{grid-template-columns:1fr}
  .site-footer__bottom{flex-direction:column;align-items:flex-start;gap:8px}
  .site-footer__legal-link{min-height:44px}
  .site-footer__link{min-height:44px}
  .breadcrumb{font-size:12px}
}

/* ---------- 16. 动效降级 ---------- */
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  .to-top{transform:none}
  .site-header__progress-bar{transition:none}
}

/* ---------- 17. 打印 ---------- */
@media print{
  .site-header,.site-footer,.to-top,.skip-link{display:none !important}
  body{background:#fff;color:#111;font-size:12pt}
  h1,h2,h3,.display,.lede{color:#111}
}