/* BOB赛场 · 共享样式 /assets/site.css */
*,*::before,*::after{box-sizing:border-box}

:root{
  --void-black:#05080F;
  --deep-space:#0A1428;
  --panel-blue:#122238;
  --line-blue:#22405F;
  --deep-green:#0B3B2E;
  --track-green:#17D08A;
  --signal-orange:#FF5A1F;
  --orange-glow:#FF8A4C;
  --live-cyan:#38F2E8;
  --chalk-white:#F2F6FF;
  --mist-grey:#93A4BF;

  --edge:1px solid rgba(34,64,95,.85);
  --edge-soft:1px solid rgba(34,64,95,.5);
  --fill-soft:rgba(18,34,56,.62);
  --ink-on-orange:#160600;

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

  --shell-max:1240px;
  --gutter:clamp(18px,4.2vw,56px);
  --radius-lg:24px;
  --radius-md:14px;
  --radius-sm:8px;
  --header-h:76px;
}

html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;
  background:var(--void-black);
  color:var(--chalk-white);
  font-family:var(--font-sans);
  font-size:clamp(16px,.35vw + 15px,18px);
  line-height:1.75;
  font-weight:400;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
body.nav-open{overflow:hidden}

h1,h2,h3,h4,p,figure,blockquote,ul,ol,dl{margin:0}
ul,ol{padding:0;list-style:none}
img,svg,video{max-width:100%;height:auto;display:block}
a{color:inherit}
button{font:inherit}
h1,h2,h3,h4{font-weight:800;letter-spacing:-.02em;line-height:1.14}

:focus-visible{outline:2px solid var(--signal-orange);outline-offset:3px;border-radius:4px}

.shell{
  width:min(var(--shell-max),calc(100% - var(--gutter) * 2));
  margin-inline:auto;
}

.skip-link{
  position:absolute;
  left:50%;
  top:0;
  z-index:200;
  transform:translate(-50%,-140%);
  background:var(--signal-orange);
  color:var(--ink-on-orange);
  font-size:15px;
  font-weight:700;
  padding:10px 22px;
  border-radius:0 0 var(--radius-sm) var(--radius-sm);
  text-decoration:none;
  transition:transform .22s ease;
}
.skip-link:focus{transform:translate(-50%,0)}

/* ---------- 头部 ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:60;
  background:transparent;
  border-bottom:1px solid transparent;
  transition:background-color .32s ease,border-color .32s ease;
}
.site-header[data-scrolled]{
  background:rgba(5,8,15,.95);
  border-bottom-color:var(--line-blue);
}
.header-shell{
  display:flex;
  align-items:center;
  gap:clamp(14px,2.2vw,36px);
  padding-block:18px;
  transition:padding .3s ease;
}
.site-header[data-scrolled] .header-shell{padding-block:10px}

.brand{
  display:inline-flex;
  align-items:center;
  gap:11px;
  text-decoration:none;
  flex:none;
}
.brand-mark{
  width:34px;
  height:34px;
  flex:none;
  display:grid;
  place-items:center;
  background:linear-gradient(150deg,var(--signal-orange),var(--orange-glow));
  clip-path:polygon(0 0,100% 0,100% 72%,72% 100%,0 100%);
}
.brand-mark-lane{
  width:18px;
  height:18px;
  background-image:repeating-linear-gradient(115deg,var(--void-black) 0 2px,transparent 2px 6px);
}
.brand-text{display:flex;flex-direction:column;line-height:1.2}
.brand-name{
  font-size:19px;
  font-weight:800;
  letter-spacing:-.02em;
  color:var(--chalk-white);
}
.brand-suffix{
  font-size:11px;
  letter-spacing:.16em;
  color:var(--mist-grey);
}

.site-nav{margin-left:auto}
.nav-track{display:flex;align-items:center;gap:clamp(12px,1.6vw,26px)}
.nav-node{display:block}
.nav-link{
  position:relative;
  display:inline-block;
  padding:8px 2px;
  font-size:15px;
  font-weight:600;
  color:var(--mist-grey);
  text-decoration:none;
  white-space:nowrap;
  transition:color .2s ease;
}
.nav-link::after{
  content:"";
  position:absolute;
  left:0;
  right:100%;
  bottom:2px;
  height:2px;
  background:linear-gradient(90deg,var(--signal-orange),var(--orange-glow));
  transition:right .28s cubic-bezier(.2,.7,.3,1);
}
.nav-link:hover{color:var(--chalk-white)}
.nav-link:hover::after{right:0}
.nav-link[aria-current="page"]{color:var(--chalk-white)}
.nav-link[aria-current="page"]::after{
  right:0;
  background:linear-gradient(90deg,var(--signal-orange),var(--live-cyan));
}

.header-actions{
  display:flex;
  align-items:center;
  gap:12px;
  flex:none;
}

.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:8px;
  min-height:44px;
  padding:11px 20px;
  border:1px solid rgba(34,64,95,.9);
  border-radius:999px;
  background:var(--panel-blue);
  color:var(--chalk-white);
  font-size:15px;
  font-weight:700;
  letter-spacing:.01em;
  text-decoration:none;
  cursor:pointer;
  white-space:nowrap;
  transition:background-color .22s ease,color .22s ease,border-color .22s ease,transform .22s ease;
}
.btn:hover{transform:translateY(-1px)}
.btn-primary{background:var(--signal-orange);color:var(--ink-on-orange);border-color:transparent}
.btn-primary:hover{background:var(--orange-glow)}
.btn-ghost{background:transparent;color:var(--chalk-white)}
.btn-ghost:hover{background:rgba(23,208,138,.12);border-color:rgba(23,208,138,.5)}

.nav-toggle{
  display:none;
  width:46px;
  height:44px;
  padding:0;
  background:rgba(18,34,56,.75);
  border:1px solid rgba(34,64,95,.9);
  border-radius:12px;
  cursor:pointer;
  color:var(--chalk-white);
}
.nav-toggle-bar{
  display:block;
  width:18px;
  height:1.5px;
  margin:4px auto;
  background:currentColor;
  transition:transform .24s ease,opacity .24s ease;
}
.nav-toggle-label{
  position:absolute;
  width:1px;height:1px;
  overflow:hidden;
  clip-path:inset(50%);
  white-space:nowrap;
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:first-of-type{transform:translate(-4.5px,2.75px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:last-of-type{transform:translate(4.5px,-2.75px) rotate(-45deg)}

.track-progress{
  position:absolute;
  left:0;
  right:0;
  bottom:-1px;
  height:2px;
  background:rgba(34,64,95,.45);
}
.track-progress-bar{
  display:block;
  height:100%;
  width:100%;
  transform:scaleX(0);
  transform-origin:left center;
  background:linear-gradient(90deg,var(--track-green),var(--signal-orange));
}

/* ---------- 页脚 ---------- */
.site-footer{
  position:relative;
  margin-top:clamp(56px,9vw,140px);
  padding-top:2px;
  background:linear-gradient(180deg,var(--deep-space),var(--void-black) 70%);
}
.footer-speedline{
  height:2px;
  background:linear-gradient(90deg,transparent,var(--track-green) 20%,var(--signal-orange) 66%,transparent);
}
.footer-shell{
  display:grid;
  grid-template-columns:minmax(0,1fr) minmax(0,1.75fr) minmax(0,1.1fr);
  gap:clamp(28px,4vw,56px);
  padding-block:clamp(44px,6vw,80px) 0;
}
.footer-brand{display:flex;flex-direction:column;gap:18px}
.footer-tagline{
  font-size:14px;
  line-height:1.7;
  color:var(--mist-grey);
  max-width:24em;
}
.footer-nav{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:clamp(18px,2.6vw,36px);
}
.footer-col-title{
  font-size:12px;
  font-weight:700;
  letter-spacing:.2em;
  color:var(--track-green);
  margin-bottom:14px;
}
.footer-list{display:flex;flex-direction:column;gap:10px}
.footer-list a{
  font-size:15px;
  color:var(--mist-grey);
  text-decoration:none;
  transition:color .2s ease;
}
.footer-list a:hover{color:var(--chalk-white)}

.footer-contact{
  padding:clamp(18px,2.4vw,26px);
  background:var(--fill-soft);
  border:var(--edge-soft);
  border-radius:var(--radius-md);
}
.contact-line{
  display:flex;
  flex-wrap:wrap;
  gap:4px 12px;
  font-size:14px;
  padding-block:7px;
  border-bottom:var(--edge-soft);
}
.contact-label{
  flex:none;
  min-width:5.5em;
  color:var(--mist-grey);
  font-size:13px;
}
.contact-value{color:var(--chalk-white);word-break:break-all}
.contact-note{
  margin-top:14px;
  font-size:12.5px;
  line-height:1.7;
  color:var(--mist-grey);
}
.mono{font-family:var(--font-mono);letter-spacing:-.01em}

.footer-legal{
  width:min(var(--shell-max),calc(100% - var(--gutter) * 2));
  margin:clamp(36px,5vw,64px) auto 0;
  padding-block:20px 30px;
  border-top:var(--edge-soft);
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px 26px;
  font-size:13px;
  color:var(--mist-grey);
}
.footer-line{color:var(--mist-grey)}
.footer-copy{color:var(--mist-grey)}
.footer-icp{margin-left:auto;font-family:var(--font-mono);color:var(--line-blue)}

/* ---------- 章节与排版 ---------- */
.section{
  padding-block:clamp(48px,8vw,120px);
  position:relative;
}
.section-head{display:flex;flex-direction:column;gap:14px;margin-bottom:clamp(24px,3.4vw,48px)}
.chapter-no{
  font-family:var(--font-mono);
  font-size:14px;
  font-weight:700;
  letter-spacing:.1em;
  color:var(--signal-orange);
}
.chapter-title{
  font-size:clamp(32px,6vw,88px);
  line-height:1.04;
  letter-spacing:-.03em;
}
.section-title{font-size:clamp(22px,3vw,36px)}
.eyebrow{
  font-size:12.5px;
  font-weight:700;
  letter-spacing:.2em;
  color:var(--track-green);
}
.lede{
  font-size:clamp(17px,1.4vw,21px);
  line-height:1.7;
  color:var(--mist-grey);
  max-width:34em;
}
.prose{max-width:38em;color:var(--mist-grey);line-height:1.8}
.prose p + p{margin-top:1em}
.prose strong{color:var(--chalk-white);font-weight:700}

.grid-12{
  display:grid;
  grid-template-columns:repeat(12,minmax(0,1fr));
  gap:clamp(20px,2.4vw,32px);
}
.col-rail{grid-column:1 / span 3}
.col-main{grid-column:4 / span 8}
.rail-sticky{position:sticky;top:calc(var(--header-h) + 24px)}

.speedline{
  display:block;
  height:1px;
  width:100%;
  border:0;
  background:linear-gradient(90deg,transparent,var(--line-blue) 16%,var(--track-green) 58%,var(--signal-orange) 88%,transparent);
  opacity:.9;
}

/* ---------- 图片容器 ---------- */
.figure{display:flex;flex-direction:column;gap:12px}
.figure-frame{
  position:relative;
  overflow:hidden;
  border:var(--edge-soft);
  border-radius:var(--radius-lg);
  aspect-ratio:16 / 9;
  background:
    radial-gradient(120% 100% at 14% 0%,rgba(23,208,138,.18),transparent 56%),
    radial-gradient(90% 90% at 90% 100%,rgba(255,90,31,.16),transparent 60%),
    linear-gradient(160deg,var(--deep-space),var(--void-black) 72%);
}
.figure-frame--tall{aspect-ratio:4 / 5}
.figure-art{
  position:absolute;
  inset:0;
  background-image:
    repeating-linear-gradient(118deg,rgba(242,246,255,.06) 0 1px,transparent 1px 18px),
    radial-gradient(closest-side,rgba(56,242,232,.22),transparent);
  background-position:center;
  background-repeat:no-repeat;
}
.figure-media{
  position:relative;
  width:100%;
  height:100%;
  object-fit:cover;
}
.figure-cap{
  font-size:13px;
  line-height:1.6;
  color:var(--mist-grey);
}

/* ---------- 面包屑与状态 ---------- */
.breadcrumbs{
  font-size:13px;
  color:var(--mist-grey);
  padding-block:18px 0;
}
.crumbs{display:flex;flex-wrap:wrap;align-items:center;gap:8px}
.crumbs li{display:flex;align-items:center;gap:8px}
.crumbs a{color:var(--mist-grey);text-decoration:none}
.crumbs a:hover{color:var(--chalk-white)}
.crumbs li + li::before{content:"/";color:var(--line-blue)}
.crumbs [aria-current="page"]{color:var(--chalk-white)}

.badge-live{
  display:inline-flex;
  align-items:center;
  gap:7px;
  padding:4px 12px;
  border:1px solid rgba(56,242,232,.45);
  border-radius:999px;
  font-family:var(--font-mono);
  font-size:12px;
  font-weight:700;
  letter-spacing:.08em;
  color:var(--live-cyan);
}
.badge-live::before{
  content:"";
  width:7px;
  height:7px;
  border-radius:50%;
  background:var(--live-cyan);
  animation:bob-pulse 2.4s ease-in-out infinite;
}
@keyframes bob-pulse{
  0%,100%{opacity:1;transform:scale(1)}
  50%{opacity:.35;transform:scale(.82)}
}

.stat-num{
  display:block;
  font-family:var(--font-mono);
  font-weight:700;
  font-size:clamp(28px,5vw,64px);
  line-height:1;
  letter-spacing:-.03em;
  color:var(--chalk-white);
}

/* ---------- 滚动显现 ---------- */
.js-ready .reveal{
  opacity:0;
  transform:translateY(12px);
  transition:opacity .6s ease,transform .6s cubic-bezier(.2,.7,.3,1);
}
.js-ready .reveal[data-shown]{
  opacity:1;
  transform:none;
}

/* ---------- 平板 ---------- */
@media (max-width:1024px){
  .footer-shell{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}
  .footer-nav{grid-column:1 / -1;order:3}
  .col-rail{grid-column:1 / span 4}
  .col-main{grid-column:5 / span 8}
}

/* ---------- 移动端 ---------- */
@media (max-width:900px){
  :root{--header-h:64px}
  .header-shell{padding-block:12px;gap:12px}
  .site-header[data-scrolled] .header-shell{padding-block:8px}
  .brand-suffix{display:none}
  .header-actions{margin-left:auto}
  .header-actions .btn{font-size:13px;min-height:40px;padding:9px 15px}
  .nav-toggle{display:block}

  .site-nav{
    position:fixed;
    top:0;
    right:0;
    bottom:0;
    left:auto;
    width:min(340px,86vw);
    margin:0;
    padding:104px 26px 40px;
    background:linear-gradient(180deg,rgba(10,20,40,.99),rgba(5,8,15,.99));
    border-left:1px solid var(--line-blue);
    overflow-y:auto;
    visibility:hidden;
    transform:translateX(100%);
    transition:transform .34s cubic-bezier(.2,.8,.25,1),visibility .34s linear;
    z-index:70;
  }
  .site-nav[data-open]{
    visibility:visible;
    transform:translateX(0);
  }
  .nav-track{flex-direction:column;align-items:stretch;gap:0}
  .nav-node{border-bottom:var(--edge-soft)}
  .nav-link{display:block;padding:15px 0;font-size:17px}
  .nav-link::after{bottom:9px}

  .grid-12{grid-template-columns:minmax(0,1fr)}
  .col-rail,.col-main{grid-column:1 / -1}
  .rail-sticky{position:static}
}

@media (max-width:640px){
  .footer-shell{grid-template-columns:minmax(0,1fr)}
  .footer-nav{grid-template-columns:minmax(0,1fr)}
  .footer-icp{margin-left:0}
}

@media (max-width:480px){
  .header-actions .btn{display:none}
}

/* ---------- 降低动态效果 ---------- */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  .js-ready .reveal{opacity:1;transform:none}
  .badge-live::before{animation:none;opacity:1}
}