/* =========================================================
   体育安装看台 · qyg-arena.com.cn
   /assets/site.css — 全站共享外壳：重置 / 变量 / 中文排版 /
   头部 / 页脚 / 基础组件
   ========================================================= */

/* ---------- 01 重置 ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:clamp(88px,12vh,132px)}
body{margin:0}
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%}
button{background:none;border:0;padding:0;color:inherit;font:inherit;cursor:pointer}
a{color:inherit;text-decoration:none}
table{border-collapse:collapse;width:100%}
::selection{background:rgba(53,240,208,.28);color:var(--ice)}

/* ---------- 02 变量 ---------- */
:root{
  --deep:#06111F;
  --layer:#0C1B2E;
  --cyan:#35F0D0;
  --signal:#FF7A2F;
  --ice:#EAF2FF;
  --muted:#93A4BC;
  --line:#1E3550;
  --violet:#4C6BB3;
  --paper:#C9D6E6;
  --amber:#FFC24B;

  --shell-max:1320px;
  --gutter:clamp(20px,4vw,56px);
  --rail:320px;
  --gap:clamp(32px,5vw,88px);

  --font-sans:system-ui,-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC",sans-serif;
  --font-mono:ui-monospace,"SFMono-Regular",Menlo,Consolas,"Courier New",monospace;

  --ease:cubic-bezier(.22,.61,.36,1);
}

/* ---------- 03 基础排版 ---------- */
body{
  min-height:100vh;
  background-color:var(--deep);
  color:var(--ice);
  font-family:var(--font-sans);
  font-size:16px;
  font-weight:300;
  line-height:1.9;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
body::before{
  content:"";
  position:fixed;
  inset:0;
  z-index:-1;
  pointer-events:none;
  background:
    radial-gradient(900px 520px at 10% -8%, rgba(53,240,208,.10), transparent 62%),
    radial-gradient(780px 460px at 98% 2%, rgba(76,107,179,.22), transparent 66%),
    radial-gradient(700px 420px at 46% 108%, rgba(255,122,47,.07), transparent 70%);
}
h1,h2,h3,h4,h5,h6{font-weight:800;line-height:1.25;letter-spacing:.01em;color:var(--ice)}
p{color:var(--muted)}
strong{color:var(--ice);font-weight:600}

.display-1{font-size:clamp(44px,8vw,88px);font-weight:900;line-height:1.02;letter-spacing:-.01em}
.display-2{font-size:clamp(32px,5vw,56px);font-weight:800;line-height:1.08}
.display-3{font-size:clamp(22px,2.6vw,30px);font-weight:800;line-height:1.3}
.lede{font-size:clamp(17px,1.6vw,20px);line-height:1.85;color:var(--ice);font-weight:300;max-width:34em}
.prose{max-width:36em;font-weight:300;font-size:16px;line-height:1.9;color:var(--muted)}
.prose p+p{margin-top:1.05em}
.data-num{
  font-family:var(--font-mono);
  font-weight:500;
  letter-spacing:.08em;
  font-variant-numeric:tabular-nums;
  color:var(--cyan);
}
.annotation{
  font-size:12px;
  letter-spacing:.3em;
  color:rgba(234,242,255,.6);
  writing-mode:vertical-rl;
  text-orientation:mixed;
  line-height:1;
}

/* ---------- 04 布局容器 ---------- */
.shell{
  width:100%;
  max-width:var(--shell-max);
  margin-inline:auto;
  padding-inline:var(--gutter);
}
.page-main{display:block;padding-block:clamp(24px,3vw,48px) 0}
.rail-layout{
  display:grid;
  grid-template-columns:var(--rail) minmax(0,1fr);
  gap:var(--gap);
  align-items:start;
}
.rail{
  position:sticky;
  top:clamp(120px,16vh,168px);
  display:flex;
  flex-direction:column;
  gap:16px;
}
.content-col{min-width:0}
.grid{display:grid;gap:clamp(16px,2vw,24px)}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}

/* ---------- 05 焦点与无障碍 ---------- */
:focus-visible{outline:2px solid var(--cyan);outline-offset:3px;border-radius:1px}
.skip-link{
  position:absolute;
  left:14px;
  top:-64px;
  z-index:200;
  padding:10px 18px;
  background:var(--cyan);
  color:#04131C;
  font-size:13px;
  font-weight:600;
  letter-spacing:.08em;
  border-radius:2px;
  transition:top 200ms var(--ease);
}
.skip-link:focus{top:14px}

/* ---------- 06 按钮 ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  padding:10px 16px;
  border:1px solid transparent;
  border-radius:2px;
  font-size:13px;
  font-weight:500;
  letter-spacing:.08em;
  line-height:1.2;
  white-space:nowrap;
  transition:background-color 240ms var(--ease),color 240ms var(--ease),border-color 240ms var(--ease),transform 240ms var(--ease);
}
.btn--signal{
  background:var(--signal);
  color:#180B02;
  font-weight:600;
}
.btn--signal:hover{background:#FF9A5C;transform:translateY(-1px)}
.btn--ghost{
  background:transparent;
  color:var(--ice);
  border-color:var(--line);
}
.btn--ghost:hover{border-color:var(--cyan);color:var(--cyan)}
.btn--block{width:100%}

/* ---------- 07 页头 ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:90;
  background:rgba(6,17,31,.92);
  -webkit-backdrop-filter:blur(14px);
  backdrop-filter:blur(14px);
  border-bottom:1px solid var(--line);
}
.site-header__inner{position:relative}
.site-header__bar{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:clamp(14px,2.4vw,32px);
  padding-block:16px;
  transition:padding 280ms var(--ease);
}
.brand{display:inline-flex;align-items:center;gap:10px;flex:0 0 auto}
.brand__mark{
  position:relative;
  width:20px;height:20px;
  border:1px solid var(--cyan);
  border-radius:2px;
  background:linear-gradient(180deg,rgba(53,240,208,.18),rgba(53,240,208,0));
}
.brand__mark::after{
  content:"";
  position:absolute;
  left:50%;top:50%;
  width:9px;height:9px;
  border:1px solid rgba(53,240,208,.7);
  border-radius:50%;
  transform:translate(-50%,-50%);
}
.brand__name{font-size:15px;font-weight:800;letter-spacing:.06em;color:var(--ice);white-space:nowrap}
.brand__dot{color:var(--cyan);font-weight:400;margin-inline:5px}
.brand--footer .brand__name{font-size:17px}

.header-actions{display:flex;align-items:center;gap:10px;flex:0 0 auto}

.status-line{
  display:inline-flex;
  align-items:center;
  gap:9px;
  margin-left:auto;
  font-size:11px;
  letter-spacing:.24em;
  color:var(--muted);
  white-space:nowrap;
  transition:opacity 240ms var(--ease),visibility 240ms var(--ease);
}
.status-line__dot{
  width:7px;height:7px;
  border-radius:50%;
  background:var(--cyan);
  animation:pulse 2.4s ease-out infinite;
}
@keyframes pulse{
  0%{box-shadow:0 0 0 0 rgba(53,240,208,.5)}
  70%{box-shadow:0 0 0 10px rgba(53,240,208,0)}
  100%{box-shadow:0 0 0 0 rgba(53,240,208,0)}
}

.nav-toggle{
  display:none;
  align-items:center;
  gap:9px;
  padding:8px 12px;
  border:1px solid var(--line);
  border-radius:2px;
  color:var(--ice);
  font-size:12px;
  letter-spacing:.18em;
}
.nav-toggle__bars{position:relative;display:block;width:16px;height:10px}
.nav-toggle__bars::before,
.nav-toggle__bars::after{
  content:"";
  position:absolute;
  left:0;right:0;
  height:1px;
  background:var(--cyan);
  transition:transform 260ms var(--ease);
}
.nav-toggle__bars::before{top:0}
.nav-toggle__bars::after{bottom:0}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before{transform:translateY(4.5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after{transform:translateY(-4.5px) rotate(-45deg)}

.site-nav{
  border-top:1px solid var(--line);
  padding-block:12px;
  transition:padding 280ms var(--ease);
}
.site-nav__list{display:flex;flex-wrap:wrap;gap:clamp(18px,3.4vw,44px)}
.site-nav__link{
  position:relative;
  display:inline-block;
  padding-block:6px;
  font-size:13.5px;
  font-weight:300;
  letter-spacing:.14em;
  color:var(--muted);
  transition:color 220ms var(--ease);
}
.site-nav__link::after{
  content:"";
  position:absolute;
  left:0;right:0;bottom:0;
  height:1px;
  background:var(--cyan);
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform 260ms var(--ease);
}
.site-nav__link:hover{color:var(--ice)}
.site-nav__link:hover::after{transform:scaleX(1)}
.site-nav__link[aria-current="page"]{color:var(--ice);font-weight:500}
.site-nav__link[aria-current="page"]::after{transform:scaleX(1)}

.site-header[data-condensed="true"] .site-header__bar{padding-block:9px}
.site-header[data-condensed="true"] .site-nav{padding-block:8px}
.site-header[data-condensed="true"] .status-line{opacity:0;visibility:hidden}

.scroll-progress{height:2px;background:rgba(30,53,80,.6)}
.scroll-progress__bar{
  display:block;
  height:100%;
  width:100%;
  transform:scaleX(0);
  transform-origin:left center;
  background:linear-gradient(90deg,var(--cyan),var(--signal));
}

/* ---------- 08 页脚 ---------- */
.site-footer{
  margin-top:clamp(64px,9vw,120px);
  padding-block:clamp(48px,6vw,80px) 26px;
  border-top:1px solid var(--line);
  background:linear-gradient(180deg,rgba(12,27,46,0),rgba(12,27,46,.92) 42%,#071527);
}
.site-footer__top{
  display:grid;
  grid-template-columns:minmax(220px,.9fr) minmax(0,2.4fr);
  gap:clamp(28px,4vw,64px);
  align-items:start;
}
.site-footer__brand{display:flex;flex-direction:column;align-items:flex-start;gap:18px}
.site-footer__tag{
  font-size:14px;
  font-weight:300;
  line-height:1.9;
  color:var(--muted);
  max-width:20em;
}
.footer-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:clamp(18px,2.4vw,36px)}
.footer-col__title{
  font-size:11px;
  font-weight:500;
  letter-spacing:.28em;
  color:var(--cyan);
  margin-bottom:16px;
}
.footer-col__title::after{content:"";display:block;width:22px;height:1px;background:var(--line);margin-top:10px}
.footer-col__list{display:flex;flex-direction:column;gap:2px}
.footer-link{
  display:inline-block;
  font-size:13.5px;
  line-height:1.95;
  color:var(--muted);
  transition:color 200ms var(--ease);
}
.footer-link:hover{color:var(--ice)}
.footer-link__value{
  font-family:var(--font-mono);
  font-size:12.5px;
  letter-spacing:.02em;
  word-break:break-all;
  color:var(--muted);
}
.footer-link:hover .footer-link__value{color:var(--cyan)}

.site-footer__contact{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:12px 28px;
  margin-top:clamp(32px,4vw,56px);
  padding:16px 20px;
  border:1px solid var(--line);
  border-radius:2px;
  background:rgba(233,240,255,.03);
}
.contact-line{font-size:13px;line-height:1.7;color:var(--muted);font-weight:300}
.contact-line__key{
  display:inline-block;
  margin-right:9px;
  font-size:11px;
  letter-spacing:.22em;
  color:var(--cyan);
}
.copy-btn{
  padding:7px 13px;
  border:1px solid var(--line);
  border-radius:2px;
  font-size:12px;
  letter-spacing:.1em;
  color:var(--ice);
  transition:border-color 220ms var(--ease),color 220ms var(--ease);
}
.copy-btn:hover{border-color:var(--signal);color:var(--signal)}

.site-footer__legal{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:14px 24px;
  margin-top:clamp(24px,3vw,36px);
  padding-top:18px;
  border-top:1px solid var(--line);
  font-size:12px;
  letter-spacing:.08em;
  color:var(--muted);
}
.legal-list{display:flex;flex-wrap:wrap;gap:20px}
.legal-link{color:var(--muted);transition:color 200ms var(--ease)}
.legal-link:hover{color:var(--cyan)}
.site-footer__icp{font-family:var(--font-mono);font-size:12px;letter-spacing:.06em;color:var(--muted)}
.copy-status{min-height:1.4em;margin-top:10px;font-size:12px;letter-spacing:.1em;color:var(--cyan)}

/* ---------- 09 章节与双栏组件 ---------- */
.section-block{
  padding-block:clamp(40px,6vw,80px);
  border-top:1px solid var(--line);
}
.section-block:first-of-type{border-top:0;padding-top:clamp(16px,2vw,28px)}
.section-head{
  display:flex;
  flex-wrap:wrap;
  align-items:baseline;
  justify-content:space-between;
  gap:14px 28px;
  margin-bottom:22px;
}
.section-index{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.28em;
  color:var(--cyan);
}
.section-rule{position:relative;height:1px;background:var(--line);overflow:hidden;margin-block:18px}
.section-rule::after{
  content:"";
  position:absolute;
  inset:0;
  background:linear-gradient(90deg,var(--cyan),rgba(53,240,208,0));
  transform:scaleX(0);
  transform-origin:left center;
  transition:transform 360ms var(--ease);
}
[data-reveal].is-visible .section-rule::after,
.section-rule.is-visible::after{transform:scaleX(1)}

.rail__block{
  padding:18px;
  border:1px solid var(--line);
  border-left:2px solid rgba(53,240,208,.5);
  border-radius:2px;
  background:var(--layer);
}
.rail__label{
  display:block;
  margin-bottom:12px;
  font-size:11px;
  letter-spacing:.3em;
  color:var(--cyan);
}

.side-index{border-left:1px solid var(--line);padding-left:18px}
.side-index__title{
  margin-bottom:12px;
  font-size:11px;
  font-weight:500;
  letter-spacing:.3em;
  color:var(--muted);
}
.side-index__list{display:flex;flex-direction:column}
.side-index__link{
  display:flex;
  align-items:baseline;
  gap:10px;
  padding:7px 0;
  font-size:13px;
  letter-spacing:.06em;
  color:var(--muted);
  transition:color 200ms var(--ease);
}
.side-index__link:hover{color:var(--ice)}
.side-index__link[aria-current="true"]{color:var(--cyan)}
.side-index__num{font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;opacity:.85}

/* ---------- 10 卡片 / 标签 / 面包屑 ---------- */
.card{
  padding:clamp(18px,2.4vw,28px);
  border:1px solid var(--line);
  border-radius:2px;
  background:var(--layer);
}
.card--paper{
  background:linear-gradient(160deg,rgba(201,214,230,.10),rgba(12,27,46,.94));
}
.card--link{transition:border-color 240ms var(--ease),transform 240ms var(--ease)}
.card--link:hover{border-color:var(--cyan);transform:translateY(-2px)}
.card__title{font-size:17px;font-weight:700;line-height:1.5;color:var(--ice)}
.card__meta{margin-top:10px;font-size:12px;letter-spacing:.16em;color:var(--muted)}

.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:4px 10px;
  border:1px solid var(--line);
  border-radius:2px;
  background:rgba(233,240,255,.03);
  font-size:12px;
  letter-spacing:.16em;
  color:var(--muted);
}
.tag--cyan{border-color:rgba(53,240,208,.5);color:var(--cyan)}
.tag--amber{border-color:rgba(255,194,75,.5);color:var(--amber)}

.breadcrumb{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:10px;
  font-size:12px;
  letter-spacing:.16em;
  color:var(--muted);
}
.breadcrumb__link{color:var(--muted);transition:color 200ms var(--ease)}
.breadcrumb__link:hover{color:var(--cyan)}

/* ---------- 11 图片容器 ---------- */
.media{
  position:relative;
  width:100%;
  aspect-ratio:16/9;
  overflow:hidden;
  border:1px solid var(--line);
  border-radius:2px;
  background:linear-gradient(150deg,var(--layer),#08192B 58%,rgba(76,107,179,.38));
}
.media img{width:100%;height:100%;object-fit:cover}
.media--tall{aspect-ratio:4/5}
.media--square{aspect-ratio:1}
.media__caption{
  position:absolute;
  left:0;bottom:0;
  padding:10px 14px;
  font-size:12px;
  letter-spacing:.16em;
  color:rgba(234,242,255,.72);
  background:linear-gradient(0deg,rgba(6,17,31,.85),rgba(6,17,31,0));
  width:100%;
}

/* ---------- 12 数据条与动效 ---------- */
.data-bar{display:flex;align-items:center;gap:12px}
.data-bar__track{
  position:relative;
  flex:1 1 auto;
  height:6px;
  border:1px solid var(--line);
  background:rgba(233,240,255,.06);
  overflow:hidden;
}
.data-bar__fill{
  display:block;
  height:100%;
  width:0;
  background:linear-gradient(90deg,var(--violet),var(--cyan));
  transition:width 420ms var(--ease);
}
.is-visible .data-bar__fill{width:var(--value,0%)}
.data-bar__value{font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--cyan)}

[data-reveal]{opacity:0;transform:translateY(16px);transition:opacity 360ms var(--ease),transform 360ms var(--ease)}
[data-reveal].is-visible{opacity:1;transform:none}
[data-stagger]{opacity:0;transform:translateY(10px);transition:opacity 300ms var(--ease),transform 300ms var(--ease)}
[data-reveal].is-visible [data-stagger]{opacity:1;transform:none}

/* ---------- 13 返回顶部 ---------- */
.back-to-top{
  position:fixed;
  right:clamp(16px,3vw,34px);
  bottom:clamp(16px,3vw,34px);
  z-index:95;
  display:grid;
  place-items:center;
  width:46px;height:46px;
  border:1px solid var(--line);
  border-radius:2px;
  background:rgba(12,27,46,.92);
  color:var(--ice);
  opacity:0;
  visibility:hidden;
  transform:translateY(8px);
  transition:opacity 260ms var(--ease),transform 260ms var(--ease),visibility 260ms var(--ease),border-color 220ms var(--ease);
}
.back-to-top[data-visible="true"]{opacity:1;visibility:visible;transform:none}
.back-to-top:hover{border-color:var(--cyan);color:var(--cyan)}
.back-to-top__icon{
  display:block;
  width:9px;height:9px;
  border-left:1px solid currentColor;
  border-top:1px solid currentColor;
  transform:rotate(45deg) translate(1px,1px);
}

/* ---------- 14 响应式 ---------- */
@media (max-width:1100px){
  :root{--rail:280px;--gap:clamp(28px,4vw,56px)}
}
@media (max-width:980px){
  .site-footer__top{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .rail-layout{grid-template-columns:1fr}
  .rail{position:static}
}
@media (max-width:900px){
  .nav-toggle{display:inline-flex}
  .site-nav{
    max-height:0;
    overflow:hidden;
    visibility:hidden;
    opacity:0;
    border-top:0;
    padding-block:0;
    transition:max-height 320ms var(--ease),opacity 220ms var(--ease),padding 320ms var(--ease),visibility 320ms var(--ease);
  }
  .site-nav[data-open="true"]{
    max-height:75vh;
    overflow-y:auto;
    visibility:visible;
    opacity:1;
    border-top:1px solid var(--line);
    padding-block:8px 18px;
  }
  .site-nav__list{flex-direction:column;gap:0}
  .site-nav__link{
    display:block;
    padding:15px 2px;
    font-size:16px;
    letter-spacing:.12em;
    border-bottom:1px solid var(--line);
  }
  .site-nav__link::after{display:none}
  .site-nav__link[aria-current="page"]{color:var(--cyan)}
  .status-line{display:none}
  .site-header[data-condensed="true"] .site-nav{padding-block:0}
  .site-header[data-condensed="true"] .site-nav[data-open="true"]{padding-block:8px 18px}
  .grid--3{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (max-width:620px){
  body{font-size:15.5px}
  .header-actions__ghost{display:none}
  .grid--2,.grid--3{grid-template-columns:1fr}
  .site-footer__legal{flex-direction:column;align-items:flex-start;gap:12px}
}
@media (max-width:520px){
  .footer-grid{grid-template-columns:1fr}
  .site-footer__contact{padding:14px 16px;gap:10px 20px}
  .brand__name{font-size:14px}
}

/* ---------- 15 降低动效 ---------- */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  .status-line__dot{animation:none}
  [data-reveal],[data-stagger]{opacity:1;transform:none}
  .data-bar__fill{width:var(--value,0%)}
  .section-rule::after{transform:scaleX(1)}
}