/* ============ 博业免费赛场 / assets/site.css ============ */

/* ---------- reset ---------- */
*,*::before,*::after{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;}
body,h1,h2,h3,h4,h5,p,ul,ol,figure,blockquote,dl,dd{margin:0;}
ul,ol{padding:0;list-style:none;}
img,svg,video{display:block;max-width:100%;}
a{color:inherit;text-decoration:none;}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer;}
table{border-collapse:collapse;width:100%;}
:focus-visible{outline:2px solid #FF6A13;outline-offset:3px;}

/* ---------- tokens ---------- */
:root{
  --ink:#0A0F0C;
  --green:#123B2E;
  --rock:#1B2420;
  --orange:#FF6A13;
  --ember:#C64A0A;
  --ice:#7CD2E6;
  --silver:#C6CFCA;
  --paper:#F3F6F2;
  --moss:#2F6E54;

  --line:rgba(198,207,202,.20);
  --line-2:rgba(198,207,202,.45);
  --sunk:rgba(198,207,202,.70);

  --rail:96px;
  --bar:56px;
  --hud:56px;
  --hud-small:48px;
  --wrap:1440px;
  --gutter:24px;

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

  --t-12:12px; --t-14:14px; --t-18:18px; --t-24:24px;
  --t-34:34px; --t-52:52px; --t-88:88px; --t-144:144px;
}

/* ---------- base ---------- */
body{
  background:var(--ink);
  color:var(--paper);
  font-family:var(--font-sans);
  font-size:18px;
  line-height:1.75;
  font-weight:400;
  padding-top:var(--bar);
  padding-left:0;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
@media (min-width:1024px){
  body{padding-top:0;padding-left:var(--rail);}
}

h1,h2,h3,h4{font-weight:800;line-height:1.15;letter-spacing:-.02em;}
p{max-width:68ch;}
.mono,.num{font-family:var(--font-mono);font-variant-numeric:tabular-nums slashed-zero;}
.display{
  font-weight:900;
  font-size:clamp(56px,11vw,176px);
  line-height:.9;
  letter-spacing:-.04em;
}
.lead{font-size:18px;color:var(--silver);max-width:62ch;}
.sr-only{
  position:absolute;width:1px;height:1px;padding:0;margin:-1px;
  overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0;
}
::selection{background:var(--orange);color:var(--ink);}

/* ---------- layout ---------- */
.wrap{
  width:100%;
  max-width:var(--wrap);
  margin:0 auto;
  padding-left:clamp(16px,3vw,40px);
  padding-right:clamp(16px,3vw,40px);
}
.grid{
  display:grid;
  grid-template-columns:repeat(12,minmax(0,1fr));
  gap:var(--gutter);
}
.span-3{grid-column:span 3;}
.span-4{grid-column:span 4;}
.span-5{grid-column:span 5;}
.span-6{grid-column:span 6;}
.span-7{grid-column:span 7;}
.span-8{grid-column:span 8;}
.span-12{grid-column:span 12;}
@media (max-width:1023px){
  .grid{grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;}
  .span-3,.span-4,.span-5,.span-6,.span-7,.span-8{grid-column:span 4;}
}
.skip-link{
  position:fixed;left:12px;top:-120px;z-index:200;
  background:var(--orange);color:var(--ink);
  padding:12px 20px;font-size:14px;font-weight:700;letter-spacing:.08em;
  transition:top .18s ease;
}
.skip-link:focus{top:12px;}
@media (min-width:1024px){
  .skip-link{left:calc(var(--rail) + 12px);}
}

/* ============================================================
   HEADER — 侧边轨道导航
   ============================================================ */
.rail{
  position:fixed;
  top:0;left:0;bottom:0;
  width:var(--rail);
  z-index:80;
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:space-between;
  padding:18px 0 22px;
  background:var(--ink);
  border-right:1px solid var(--line);
}
.rail__brand{
  display:flex;flex-direction:column;align-items:center;gap:12px;
  flex:0 0 auto;
}
.rail__mark{
  display:flex;flex-direction:column;align-items:center;
  writing-mode:vertical-rl;
  font-size:20px;font-weight:900;letter-spacing:.18em;
  color:var(--paper);line-height:1;
  transition:color .18s ease;
}
.rail__mark-line{display:block;}
.rail__mark:hover{color:var(--orange);}
.rail__version{
  font-family:var(--font-mono);font-size:12px;letter-spacing:.12em;
  color:var(--silver);padding-top:10px;border-top:1px solid var(--line-2);
}
.rail__nav{
  flex:1 1 auto;min-height:0;
  display:flex;align-items:center;justify-content:center;
  margin:16px 0;
}
.rail__list{
  display:flex;flex-direction:column;align-items:center;gap:2px;
}
.rail__item{display:block;}
.rail__link{
  position:relative;
  display:flex;flex-direction:column;align-items:center;gap:6px;
  width:var(--rail);
  padding:10px 0;
  color:var(--silver);
  transition:color .18s ease;
}
.rail__link::before{
  content:"";position:absolute;left:0;top:10%;bottom:10%;width:3px;
  background:transparent;transition:background .18s ease;
}
.rail__link:hover::before{background:var(--moss);}
.rail__link:hover{color:var(--paper);}
.rail__link[aria-current="page"]{color:var(--paper);}
.rail__link[aria-current="page"]::before{background:var(--orange);}
.rail__num{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;
  color:var(--ice);transition:color .18s ease;
}
.rail__link:hover .rail__num,
.rail__link[aria-current="page"] .rail__num{color:var(--orange);}
.rail__label{
  writing-mode:vertical-rl;
  font-size:12px;letter-spacing:.18em;line-height:1;
}
.rail__flyout{
  position:absolute;left:calc(100% - 6px);top:50%;
  transform:translate(-8px,-50%);
  background:var(--green);color:var(--paper);
  border:1px solid var(--line-2);
  padding:6px 12px;font-size:12px;letter-spacing:.16em;white-space:nowrap;
  opacity:0;visibility:hidden;
  transition:opacity .18s ease,transform .18s ease,visibility .18s;
  pointer-events:none;
}
.rail__link:hover .rail__flyout,
.rail__link:focus-visible .rail__flyout{
  opacity:1;visibility:visible;transform:translate(0,-50%);
}
.rail__meta{
  flex:0 0 auto;
  display:flex;flex-direction:column;align-items:center;gap:8px;
}
.rail__tick{
  width:8px;height:8px;background:var(--orange);display:block;
}
.rail__tag{
  writing-mode:vertical-rl;
  font-size:12px;letter-spacing:.28em;color:var(--silver);max-width:none;
}
.rail__tag--ice{color:var(--ice);}
.rail__toggle{
  display:none;align-items:center;gap:10px;
  padding:8px 4px;color:var(--paper);
}
.rail__toggle-box{
  display:inline-flex;flex-direction:column;justify-content:center;gap:4px;
  width:22px;height:16px;
}
.rail__toggle-box i{
  display:block;height:2px;background:var(--paper);
  transition:transform .2s ease,opacity .2s ease;
}
.rail__toggle[aria-expanded="true"] .rail__toggle-box i:nth-child(1){transform:translateY(6px) rotate(45deg);}
.rail__toggle[aria-expanded="true"] .rail__toggle-box i:nth-child(2){opacity:0;}
.rail__toggle[aria-expanded="true"] .rail__toggle-box i:nth-child(3){transform:translateY(-6px) rotate(-45deg);}
.rail__toggle-text{
  font-size:12px;letter-spacing:.24em;color:var(--silver);
}

/* ---------- HUD：右上角常驻工具条 + 滚动进度 ---------- */
.hud{
  position:fixed;
  top:0;right:0;left:var(--rail);
  height:var(--hud);
  z-index:70;
  display:flex;align-items:center;justify-content:flex-end;gap:10px;
  padding:0 clamp(16px,3vw,40px);
  pointer-events:none;
  transition:height .22s ease,background .22s ease,border-color .22s ease;
  border-bottom:1px solid transparent;
}
.hud>*{pointer-events:auto;}
.hud[data-condensed]{
  height:var(--hud-small);
  background:linear-gradient(180deg,rgba(10,15,12,.96),rgba(10,15,12,.78));
  border-bottom-color:var(--line);
}
.hud__link{
  display:inline-flex;align-items:center;
  height:36px;padding:0 16px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.16em;
  border:1px solid var(--line-2);color:var(--silver);
  background:rgba(27,36,32,.6);
  transition:transform .18s ease,border-color .18s ease,color .18s ease,background .18s ease;
}
.hud__link:hover{transform:translateY(-2px);border-color:var(--orange);color:var(--orange);}
.hud__link--cta{
  background:var(--orange);color:var(--ink);font-weight:700;border-color:var(--orange);
}
.hud__link--cta:hover{background:var(--ember);color:var(--paper);border-color:var(--ember);}
.hud__progress{
  position:fixed;top:0;left:0;right:0;height:3px;z-index:90;
  background:rgba(198,207,202,.12);pointer-events:none;
}
.hud__progress i{
  display:block;height:100%;width:0;background:var(--orange);
}

/* ============================================================
   FOOTER
   ============================================================ */
.site-foot{
  position:relative;
  background:var(--ink);
  border-top:1px solid var(--line);
  overflow:hidden;
}
.site-foot::before{
  content:"";position:absolute;left:0;top:0;width:120px;height:3px;background:var(--orange);
}
.site-foot__top{
  display:grid;
  grid-template-columns:repeat(12,minmax(0,1fr));
  gap:36px var(--gutter);
  padding-top:clamp(48px,7vw,88px);
  padding-bottom:clamp(32px,5vw,56px);
}
.site-foot__brand{grid-column:span 3;}
.site-foot__col{grid-column:span 2;}
.site-foot__contact{grid-column:span 3;}
.site-foot__mark{
  display:inline-block;
  font-size:24px;font-weight:900;letter-spacing:-.02em;color:var(--paper);
  transition:color .18s ease;
}
.site-foot__mark:hover{color:var(--orange);}
.site-foot__line{
  margin-top:14px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.24em;color:var(--ice);
  max-width:none;
}
.site-foot__meta{
  margin-top:10px;font-size:14px;color:var(--silver);max-width:34ch;line-height:1.7;
}
.site-foot__cta{
  display:inline-flex;align-items:center;margin-top:22px;
  padding:11px 20px;font-size:14px;font-weight:700;letter-spacing:.08em;
  border:1px solid var(--orange);color:var(--orange);
  transition:background .18s ease,color .18s ease,transform .18s ease;
}
.site-foot__cta:hover{background:var(--orange);color:var(--ink);transform:translateY(-2px);}
.site-foot__title{
  font-size:12px;font-weight:700;letter-spacing:.28em;
  color:var(--ice);margin-bottom:16px;
}
.site-foot__list li{margin-bottom:10px;}
.site-foot__list a{
  font-size:15px;color:var(--silver);
  border-bottom:1px solid transparent;
  transition:color .18s ease,border-color .18s ease;
}
.site-foot__list a:hover{color:var(--orange);border-bottom-color:var(--orange);}
.site-foot__list--plain li{
  font-size:14px;line-height:1.75;color:var(--sunk);margin-bottom:12px;
}
.site-foot__watermark{
  font-size:clamp(44px,13vw,180px);
  font-weight:900;line-height:.8;letter-spacing:-.05em;
  color:rgba(198,207,202,.05);
  padding:0 clamp(16px,3vw,40px);
  white-space:nowrap;user-select:none;max-width:none;
}
.site-foot__bottom{
  display:flex;flex-wrap:wrap;align-items:center;
  gap:10px 28px;
  border-top:1px solid var(--line);
  padding-top:20px;padding-bottom:34px;
}
.site-foot__legal{
  font-family:var(--font-mono);font-size:13px;letter-spacing:.08em;color:var(--silver);
}
.site-foot__note{
  flex:1 1 320px;font-size:13px;line-height:1.7;color:var(--sunk);max-width:64ch;
}
.site-foot__year{
  margin-left:auto;font-family:var(--font-mono);font-size:13px;color:var(--silver);
}

/* ============================================================
   通用组件
   ============================================================ */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:10px;
  padding:14px 26px;
  font-size:15px;font-weight:700;letter-spacing:.08em;
  border:1px solid transparent;
  transition:transform .18s ease,background .18s ease,color .18s ease,border-color .18s ease;
}
.btn--primary{background:var(--orange);color:var(--ink);}
.btn--primary:hover{background:var(--ember);color:var(--paper);transform:translateY(-2px);}
.btn--ghost{border-color:var(--orange);color:var(--orange);}
.btn--ghost:hover{background:rgba(255,106,19,.12);transform:translateY(-2px);}
.btn--quiet{border-color:var(--line-2);color:var(--silver);}
.btn--quiet:hover{border-color:var(--ice);color:var(--ice);transform:translateY(-2px);}

.crumbs{
  display:flex;flex-wrap:wrap;align-items:center;gap:10px;
  padding:18px 0 0;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.16em;color:var(--silver);
}
.crumbs a{transition:color .18s ease;}
.crumbs a:hover{color:var(--orange);}
.crumbs__sep{color:var(--line-2);}
.crumbs [aria-current="page"]{color:var(--orange);}

.page-head{
  position:relative;
  padding:clamp(76px,10vw,150px) 0 clamp(36px,5vw,68px);
  border-bottom:1px solid var(--line);
  overflow:hidden;
}
.page-head__num{
  font-family:var(--font-mono);
  font-size:clamp(52px,9vw,120px);
  line-height:.85;letter-spacing:-.02em;
  color:rgba(198,207,202,.14);
}
.page-head__title{
  margin-top:10px;
  font-size:clamp(34px,6vw,88px);
  font-weight:900;line-height:.98;letter-spacing:-.03em;
}
.page-head__lead{margin-top:20px;font-size:18px;color:var(--silver);max-width:62ch;}
.page-head__annot{
  position:absolute;right:clamp(16px,3vw,40px);top:clamp(76px,10vw,150px);
  writing-mode:vertical-rl;
  font-size:12px;letter-spacing:.28em;color:var(--ice);
}
@media (max-width:640px){.page-head__annot{display:none;}}

.section{padding:clamp(48px,7vw,104px) 0;}
.section__head{
  display:flex;flex-wrap:wrap;align-items:flex-end;gap:14px;
  padding-bottom:16px;margin-bottom:clamp(24px,4vw,40px);
  border-bottom:1px solid var(--line);
}
.section__num{
  font-family:var(--font-mono);font-size:var(--t-18);color:var(--orange);letter-spacing:.1em;
}
.section__title{font-size:clamp(24px,3.2vw,44px);font-weight:800;}
.section__note{
  margin-left:auto;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.28em;color:var(--ice);
}

.card{
  position:relative;
  background:var(--rock);
  border:1px solid var(--line);
  padding:clamp(20px,2.4vw,28px);
  transition:transform .2s ease,border-color .2s ease,background .2s ease;
}
.card:hover{transform:translateY(-2px);border-color:var(--orange);}
.card__kicker{
  font-family:var(--font-mono);font-size:12px;letter-spacing:.2em;color:var(--ice);
}
.card__title{font-size:var(--t-24);font-weight:700;margin:10px 0 8px;line-height:1.25;}
.card__body{font-size:16px;line-height:1.7;color:var(--silver);}

.stat{
  display:flex;flex-direction:column;gap:4px;
  padding:16px 0;
  border-top:1px solid var(--line);
}
.stat__num{
  font-family:var(--font-mono);
  font-size:clamp(34px,5vw,52px);
  line-height:1;color:var(--paper);
  font-variant-numeric:tabular-nums slashed-zero;
}
.stat__num--orange{color:var(--orange);}
.stat__label{font-family:var(--font-mono);font-size:12px;letter-spacing:.28em;color:var(--silver);}

.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:4px 10px;
  border:1px solid var(--line-2);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.16em;color:var(--silver);
}
.tag--orange{border-color:var(--orange);color:var(--orange);}
.tag--ice{border-color:rgba(124,210,230,.55);color:var(--ice);}

.prose{font-size:17px;line-height:1.8;}
.prose p{margin-bottom:1.25em;color:var(--silver);max-width:68ch;}
.prose h2,.prose h3{margin:1.8em 0 .6em;color:var(--paper);}
.prose h2{font-size:clamp(24px,3vw,34px);}
.prose h3{font-size:var(--t-24);}
.prose ul,.prose ol{margin:0 0 1.4em 0;padding-left:1.2em;list-style:disc;color:var(--silver);}
.prose ol{list-style:decimal;}
.prose li{margin-bottom:.5em;}
.prose a{color:var(--ember);text-decoration:underline;text-underline-offset:4px;}
.prose a:hover{color:var(--orange);}
.prose strong{color:var(--paper);}

.slant{position:relative;height:clamp(48px,8vw,110px);overflow:hidden;}
.slant__fill{
  position:absolute;inset:0;background:var(--green);
  clip-path:polygon(0 62%,100% 0,100% 100%,0 100%);
}
.slant--flip .slant__fill{clip-path:polygon(0 0,100% 38%,100% 100%,0 100%);}

.tabs{width:100%;}
.tabs__list{
  display:flex;flex-wrap:wrap;gap:0;
  border-bottom:1px solid var(--line);
}
.tabs__btn{
  padding:14px 20px;
  font-size:15px;font-weight:700;letter-spacing:.06em;color:var(--silver);
  border-bottom:3px solid transparent;margin-bottom:-1px;
  transition:color .18s ease,border-color .18s ease;
}
.tabs__btn:hover{color:var(--paper);}
.tabs__btn[aria-selected="true"]{color:var(--orange);border-bottom-color:var(--orange);}
.tabs__panel{padding-top:clamp(20px,3vw,32px);}
.tabs__panel[hidden]{display:none;}

.img-frame{
  position:relative;display:block;width:100%;
  aspect-ratio:16/9;
  background:var(--green);
  border:1px solid var(--line);
  overflow:hidden;
}
.img-frame>img{width:100%;height:100%;object-fit:cover;}
.img-frame::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background-image:linear-gradient(rgba(198,207,202,.08) 1px,transparent 1px);
  background-size:100% 32px;
}
.img-frame--wide{aspect-ratio:21/9;}
.img-frame--tall{aspect-ratio:3/4;}
.img-frame--square{aspect-ratio:1/1;}
.img-frame__cap{
  position:absolute;left:0;bottom:0;z-index:2;
  background:rgba(10,15,12,.86);
  padding:8px 14px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.16em;color:var(--silver);
}

[data-reveal]{
  opacity:0;transform:translateY(16px);
  transition:opacity .6s ease,transform .6s ease;
}
[data-reveal].is-in{opacity:1;transform:none;}

/* ---------- 响应式：平板 / 手机 ---------- */
@media (max-width:1023px){
  .rail{
    top:0;left:0;right:0;bottom:auto;
    width:100%;height:var(--bar);
    flex-direction:row;align-items:center;justify-content:space-between;
    padding:0 16px;
    border-right:0;border-bottom:1px solid var(--line);
  }
  .rail__brand{flex-direction:row;align-items:center;gap:10px;}
  .rail__mark{
    writing-mode:horizontal-tb;
    flex-direction:row;gap:2px;
    font-size:17px;letter-spacing:.02em;
  }
  .rail__version{
    padding:0 0 0 10px;border-top:0;border-left:1px solid var(--line-2);
    font-size:11px;
  }
  .rail__meta{display:none;}
  .rail__nav{
    position:fixed;top:var(--bar);left:0;right:0;
    margin:0;flex:none;
    max-height:calc(100vh - var(--bar));
    overflow-y:auto;
    background:var(--rock);
    border-bottom:1px solid var(--line);
    transform:translateY(-10px);opacity:0;visibility:hidden;
    transition:opacity .22s ease,transform .22s ease,visibility .22s;
    z-index:75;
  }
  .rail__nav[data-open]{transform:none;opacity:1;visibility:visible;}
  .rail__list{flex-direction:column;align-items:stretch;gap:0;width:100%;}
  .rail__link{
    flex-direction:row;align-items:center;justify-content:flex-start;
    gap:14px;width:100%;padding:16px 18px;
    border-bottom:1px solid var(--line);
  }
  .rail__link::before{top:0;bottom:0;left:0;width:3px;}
  .rail__label{writing-mode:horizontal-tb;font-size:16px;letter-spacing:.06em;}
  .rail__num{font-size:12px;}
  .rail__flyout{display:none;}
  .rail__toggle{display:inline-flex;}
  .hud{
    top:auto;bottom:16px;right:16px;left:auto;
    height:auto;padding:0;background:none;border:0;
    flex-direction:column;align-items:flex-end;
  }
  .hud[data-condensed]{height:auto;background:none;border-bottom-color:transparent;}
  .hud__link--quiet{display:none;}
  .hud__link--cta{height:44px;box-shadow:0 8px 24px rgba(255,106,19,.28);}
  .site-foot__brand{grid-column:span 12;}
  .site-foot__col{grid-column:span 4;}
  .site-foot__contact{grid-column:span 12;}
}
@media (max-width:640px){
  body{font-size:17px;}
  .site-foot__col{grid-column:span 12;}
  .site-foot__year{margin-left:0;}
  .section__note{margin-left:0;width:100%;}
  .tabs__btn{padding:12px 14px;font-size:14px;}
}

@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;
  }
  [data-reveal]{opacity:1;transform:none;}
}