/* =====================================================================
   AK赛事 · shared site.css
   1 reset / 2 tokens / 3 typography / 4 shell header / 5 shell footer
   6 shared components / 7 responsive / 8 motion
   ===================================================================== */

/* ---------- 1 reset ---------- */
*,*::before,*::after{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:84px;}
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%;}
button{font:inherit;color:inherit;background:none;border:0;padding:0;cursor:pointer;}
a{color:inherit;text-decoration:none;}
table{border-collapse:collapse;width:100%;}
main{display:block;}
#main-content{scroll-margin-top:84px;}

/* ---------- 2 tokens ---------- */
:root{
  --sky-500:#1E90FF;
  --sky-900:#0B3E6F;
  --sky-100:#E6F2FF;
  --red-500:#B22222;
  --red-700:#7E1414;
  --snow:#FDFDFB;
  --barley-400:#E8B54A;
  --ink-900:#1C2430;
  --ink-500:#5B6675;
  --glacier-500:#2FA8A0;
  --grad-band:linear-gradient(135deg,#E6F2FF 0%,#FDFDFB 55%,#FFF3D6 100%);

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

  --rail-w:88px;
  --gutter:clamp(18px,4vw,56px);
  --maxw:1180px;
  --chamfer:polygon(8px 0,100% 0,100% calc(100% - 8px),calc(100% - 8px) 100%,0 100%,0 8px);
  --ease:cubic-bezier(.4,0,.2,1);
}

/* ---------- 3 typography & base ---------- */
body{
  background:var(--snow);
  color:var(--ink-900);
  font-family:var(--font-body);
  font-size:16px;
  font-weight:400;
  line-height:1.75;
  letter-spacing:.01em;
  min-height:100vh;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3{font-family:var(--font-display);font-weight:700;line-height:1.18;letter-spacing:-.02em;}
h4,h5{font-family:var(--font-body);font-weight:600;line-height:1.4;}
p{text-wrap:pretty;}
strong{font-weight:600;}
:focus-visible{outline:3px solid var(--sky-500);outline-offset:3px;}
.site-header :focus-visible{outline-color:var(--barley-400);}
::selection{background:rgba(30,144,255,.24);color:var(--ink-900);}

.visually-hidden{position:absolute!important;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;}
.num{font-family:var(--font-mono);font-variant-numeric:tabular-nums;font-feature-settings:"tnum" 1;letter-spacing:-.01em;}
.lede{font-size:clamp(17px,1.6vw,20px);line-height:1.7;color:var(--ink-500);max-width:60ch;}
.prose{max-width:68ch;font-size:16.5px;line-height:1.78;}
.prose p+p{margin-top:1.2em;}
.prose ul,.prose ol{list-style:disc;padding-left:1.35em;margin-top:1em;}
.prose li+li{margin-top:.4em;}

.skip-link{
  position:fixed;top:-120px;left:12px;z-index:200;
  padding:10px 18px;background:var(--sky-900);color:var(--snow);
  font-size:14px;letter-spacing:.08em;clip-path:var(--chamfer);
  transition:top 160ms var(--ease);
}
.skip-link:focus{top:12px;}

/* ---------- 4 header shell ---------- */
.site-header{
  position:sticky;top:0;left:0;right:0;z-index:70;
  background:var(--sky-900);
  color:var(--snow);
  box-shadow:0 1px 0 rgba(230,242,255,.18),0 14px 30px -22px rgba(11,62,111,.9);
}
.site-header::before{
  content:"";position:absolute;top:0;left:0;right:0;height:240px;z-index:0;pointer-events:none;
  background-image:
    linear-gradient(180deg,rgba(11,62,111,0) 0%,rgba(11,62,111,.88) 200px),
    repeating-linear-gradient(90deg,rgba(230,242,255,.18) 0 1px,transparent 1px 14px),
    repeating-linear-gradient(0deg,rgba(230,242,255,.18) 0 1px,transparent 1px 14px);
  background-repeat:no-repeat;
  background-size:100% 240px,100% 240px,100% 240px;
}
.rail__top,.site-nav,.rail__meta,.rail__progress{position:relative;z-index:1;}

.rail__top{
  display:flex;align-items:center;justify-content:space-between;gap:12px;
  padding:10px 16px;min-height:62px;
}
.rail__brand{display:flex;align-items:center;gap:10px;min-width:0;}
.brand-mark{
  display:grid;place-items:center;flex:0 0 auto;
  width:36px;height:36px;
  background:var(--red-500);color:var(--snow);
  font-family:var(--font-mono);font-size:14px;font-weight:700;letter-spacing:.04em;
  clip-path:var(--chamfer);
  transition:background-color 150ms var(--ease);
}
.brand-mark--ink{background:var(--sky-900);}
.rail__brand:hover .brand-mark{background:var(--red-700);}
.brand-text{display:flex;flex-direction:column;line-height:1.2;min-width:0;}
.brand-name{font-family:var(--font-display);font-weight:700;font-size:17px;letter-spacing:.04em;color:currentColor;}
.brand-sub{font-size:11px;letter-spacing:.16em;color:currentColor;opacity:.7;}

.version-badge{
  display:inline-flex;align-items:center;gap:6px;flex:0 0 auto;
  padding:4px 9px;border:1px solid rgba(232,181,74,.55);
  background:rgba(232,181,74,.14);color:var(--barley-400);
  font-size:10px;letter-spacing:.16em;clip-path:var(--chamfer);
}
.version-badge__num{font-size:12px;color:var(--snow);letter-spacing:.02em;}

.rail__toggle{
  display:inline-flex;align-items:center;gap:8px;flex:0 0 auto;
  padding:8px 12px;border:1px solid rgba(230,242,255,.32);
  color:var(--snow);font-size:12px;letter-spacing:.16em;clip-path:var(--chamfer);
  transition:background-color 150ms var(--ease),border-color 150ms var(--ease);
}
.rail__toggle:hover{background:rgba(30,144,255,.24);border-color:var(--sky-500);}
.rail__toggle-bars{display:inline-flex;flex-direction:column;gap:3px;width:16px;}
.rail__toggle-bars span{display:block;height:2px;width:100%;background:currentColor;transition:transform 180ms var(--ease),opacity 120ms var(--ease);}
.site-header[data-open="true"] .rail__toggle-bars span:nth-child(1){transform:translateY(5px) rotate(45deg);}
.site-header[data-open="true"] .rail__toggle-bars span:nth-child(2){opacity:0;}
.site-header[data-open="true"] .rail__toggle-bars span:nth-child(3){transform:translateY(-5px) rotate(-45deg);}

.site-nav{
  display:none;
  padding:0 16px 16px;
  border-top:1px solid rgba(230,242,255,.16);
}
.site-header[data-open="true"] .site-nav{display:block;}
.site-nav__list{display:flex;flex-direction:column;}
.site-nav__item{border-bottom:1px solid rgba(230,242,255,.12);}
.site-nav__link{
  display:flex;align-items:baseline;gap:12px;
  padding:13px 4px;color:rgba(253,253,251,.86);
  font-size:16px;letter-spacing:.02em;
  transition:color 150ms var(--ease),background-color 150ms var(--ease);
}
.site-nav__link:hover{color:var(--snow);background:rgba(30,144,255,.18);}
.site-nav__num{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;
  color:var(--barley-400);
  transition:background-color 150ms var(--ease),color 150ms var(--ease);
}
.site-nav__label{display:inline-block;}
.site-nav__link[aria-current="page"]{color:var(--snow);font-weight:600;}
.site-nav__link[aria-current="page"] .site-nav__num{
  background:var(--red-500);color:var(--snow);
  padding:1px 5px;clip-path:polygon(4px 0,100% 0,100% calc(100% - 4px),calc(100% - 4px) 100%,0 100%,0 4px);
}

.rail__ticks{display:none;}
.rail-tick{
  display:flex;align-items:center;justify-content:center;
  width:100%;max-width:48px;
  padding:3px 4px;border-left:2px solid transparent;
  font-family:var(--font-mono);font-size:9px;letter-spacing:.04em;
  color:rgba(230,242,255,.42);
  transition:color 150ms var(--ease),background-color 150ms var(--ease),border-color 150ms var(--ease);
}
.rail-tick:hover{color:var(--snow);background:rgba(30,144,255,.22);}
.rail-tick.is-active{color:var(--snow);border-left-color:var(--sky-500);background:rgba(30,144,255,.26);}
.rail-tick__num{line-height:1.4;}

.rail__meta{
  display:none;flex-wrap:wrap;align-items:center;gap:10px;
  padding:14px 16px 18px;
  border-top:1px solid rgba(230,242,255,.16);
}
.site-header[data-open="true"] .rail__meta{display:flex;}
.rail__member{
  display:inline-flex;align-items:center;justify-content:center;
  padding:7px 12px;font-size:11px;letter-spacing:.14em;
  color:var(--snow);border:1px solid rgba(230,242,255,.3);
  clip-path:var(--chamfer);
  transition:background-color 150ms var(--ease),border-color 150ms var(--ease),color 150ms var(--ease);
}
.rail__member:hover{background:var(--sky-500);border-color:var(--sky-500);color:#fff;}

.rail__progress{
  position:absolute;left:0;right:0;bottom:0;height:3px;
  background:rgba(230,242,255,.2);overflow:hidden;
}
.rail__progress-fill{
  display:block;height:100%;
  width:calc(var(--sp,0) * 100%);
  background:linear-gradient(90deg,var(--barley-400),var(--red-500));
  transition:width 120ms linear;
}

/* ---------- 5 footer shell ---------- */
.site-footer{
  position:relative;margin-top:clamp(56px,8vw,104px);
  color:var(--ink-900);
  background-color:var(--snow);
  background-image:
    linear-gradient(180deg,rgba(253,253,251,.25) 0%,rgba(253,253,251,.86) 60%,#FDFDFB 190px),
    repeating-linear-gradient(90deg,rgba(11,62,111,.09) 0 1px,transparent 1px 18px),
    repeating-linear-gradient(0deg,rgba(11,62,111,.09) 0 1px,transparent 1px 18px),
    linear-gradient(180deg,#EFF7FF 0%,#FDFDFB 46%,#FFF6E4 100%);
  background-repeat:no-repeat;
  background-size:100% 190px,100% 240px,100% 240px,100% 100%;
}
.footer-veil{
  position:relative;height:clamp(40px,6vw,76px);
  background:var(--grad-band);
  clip-path:polygon(0 0,100% 0,100% 100%,0 62%);
}
.footer-veil::after{
  content:"";position:absolute;left:0;right:0;bottom:0;height:4px;
  background:linear-gradient(90deg,var(--sky-500) 0%,var(--red-500) 62%,var(--barley-400) 100%);
}
.footer__inner{
  position:relative;z-index:1;
  width:100%;max-width:var(--maxw);margin-inline:auto;
  padding:clamp(26px,4vw,52px) var(--gutter) 0;
}
.footer__lead{display:flex;flex-direction:column;align-items:flex-start;gap:18px;padding-bottom:26px;border-bottom:1px solid rgba(28,36,48,.12);}
.footer__brand{display:inline-flex;align-items:center;gap:12px;}
.footer__brand:hover .brand-mark--ink{background:var(--sky-500);}
.footer__brand .brand-name{font-size:19px;}
.footer__closing{
  position:relative;padding-left:16px;
  font-family:var(--font-display);font-weight:700;
  font-size:clamp(20px,2.6vw,26px);line-height:1.42;letter-spacing:-.01em;
  max-width:22ch;color:var(--ink-900);
}
.footer__closing::before{
  content:"";position:absolute;left:0;top:.28em;bottom:.28em;width:4px;
  background:linear-gradient(180deg,var(--red-500),var(--barley-400));
}
.footer__back{margin-top:2px;}
.footer__grid{display:grid;grid-template-columns:1fr;gap:26px;padding:26px 0;}
.footer__col{min-width:0;}
.footer__col-title{
  display:flex;align-items:center;gap:8px;
  font-family:var(--font-body);font-size:12px;font-weight:500;
  letter-spacing:.16em;color:var(--ink-500);margin-bottom:12px;
}
.footer__col-title::before{content:"";width:8px;height:8px;background:var(--red-500);transform:rotate(45deg);}
.footer__list{display:flex;flex-direction:column;gap:2px;}
.footer__link{
  display:inline-block;font-size:14px;line-height:1.9;color:var(--ink-900);
  background-image:linear-gradient(currentColor,currentColor);
  background-repeat:no-repeat;background-position:0 100%;background-size:0 1px;
  transition:background-size 180ms var(--ease),color 150ms var(--ease);
}
.footer__link:hover{color:var(--sky-900);background-size:100% 1px;}
.footer__contact{font-size:14px;line-height:1.85;color:var(--ink-500);overflow-wrap:anywhere;}
.copy-btn{
  margin-top:12px;padding:6px 12px;
  border:1px solid rgba(28,36,48,.24);
  font-size:11px;letter-spacing:.14em;color:var(--ink-900);
  clip-path:var(--chamfer);
  transition:background-color 150ms var(--ease),border-color 150ms var(--ease),color 150ms var(--ease);
}
.copy-btn:hover{background:var(--sky-100);border-color:var(--sky-500);color:var(--sky-900);}
.copy-btn[data-copied="true"]{background:var(--barley-400);border-color:var(--barley-400);color:var(--ink-900);}
.footer__legal{
  display:flex;flex-wrap:wrap;gap:10px 24px;justify-content:space-between;align-items:center;
  margin-top:8px;padding:18px 0 28px;border-top:1px solid rgba(28,36,48,.12);
}
.footer__meta{font-size:12px;letter-spacing:.04em;color:var(--ink-500);}
.footer__meta-links{display:flex;flex-wrap:wrap;align-items:center;gap:8px;}
.footer__meta-links .footer__link{font-size:12px;color:var(--ink-500);}
.footer__meta-links .footer__link:hover{color:var(--sky-900);}
.footer__sep{color:rgba(91,102,117,.55);}

/* ---------- 6 shared components ---------- */
.container{width:100%;max-width:var(--maxw);margin-inline:auto;padding-inline:var(--gutter);}
.section{padding-block:clamp(40px,6vw,80px);}
.section--mist{background:linear-gradient(180deg,#F7FBFF 0%,var(--sky-100) 55%,#F7FBFF 100%);}

.chapter-head{display:grid;gap:10px;margin-bottom:clamp(22px,3vw,40px);}
.chapter-index{font-family:var(--font-mono);font-size:13px;letter-spacing:.18em;color:var(--red-500);}
.chapter-title{font-family:var(--font-display);font-weight:700;font-size:clamp(28px,4vw,52px);line-height:1.14;letter-spacing:-.02em;max-width:22ch;}
.chapter-deck{max-width:56ch;color:var(--ink-500);font-size:16px;}

.label-plate{
  display:inline-flex;align-items:center;gap:8px;
  padding:4px 10px;border:1px solid transparent;
  background:var(--sky-100);color:var(--ink-500);
  font-size:12px;letter-spacing:.16em;line-height:1.6;
  clip-path:var(--chamfer);
  transition:border-color 120ms var(--ease),background-color 150ms var(--ease),color 150ms var(--ease);
}
.label-plate:hover{border-color:var(--red-500);background:rgba(232,181,74,.16);color:var(--ink-900);}

.panel{
  position:relative;
  background:var(--snow);border:1px solid rgba(28,36,48,.12);
  padding:clamp(18px,2.4vw,26px);
  clip-path:var(--chamfer);
  transition:border-color 120ms var(--ease),background-color 150ms var(--ease);
}
.panel--link:hover{border-color:var(--sky-500);background:rgba(232,181,74,.16);}

.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:12px 22px;
  font-family:var(--font-body);font-size:14px;font-weight:600;
  letter-spacing:.08em;line-height:1.25;text-align:center;
  border:1px solid transparent;clip-path:var(--chamfer);
  transition:background-color 150ms var(--ease),color 150ms var(--ease),border-color 150ms var(--ease);
}
.btn--sky{background:var(--sky-500);color:#fff;}
.btn--sky:hover{background:var(--sky-900);}
.btn--red{background:var(--red-500);color:var(--snow);}
.btn--red:hover{background:var(--red-700);}
.btn--ghost{background:transparent;border-color:rgba(28,36,48,.26);color:var(--ink-900);}
.btn--ghost:hover{background:var(--sky-100);border-color:var(--sky-500);color:var(--sky-900);}
.btn--sm{padding:8px 14px;font-size:12px;letter-spacing:.1em;}
.btn--rail{width:100%;font-size:11px;padding:9px 6px;letter-spacing:.06em;line-height:1.35;}

.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:3px 9px;font-family:var(--font-mono);font-size:12px;letter-spacing:.06em;
  background:rgba(30,144,255,.14);color:var(--sky-900);clip-path:var(--chamfer);
}
.tag--red{background:rgba(178,34,34,.13);color:var(--red-700);}
.tag--barley{background:rgba(232,181,74,.24);color:#6B4A05;}

.grid{display:grid;gap:clamp(18px,2.6vw,36px);}
.grid--2{grid-template-columns:repeat(auto-fit,minmax(280px,1fr));}
.grid--3{grid-template-columns:repeat(auto-fit,minmax(228px,1fr));}
.grid--12{grid-template-columns:repeat(12,minmax(0,1fr));}

.rule-band{
  height:14px;
  background:linear-gradient(90deg,var(--sky-500) 0%,var(--sky-100) 52%,var(--barley-400) 100%);
  clip-path:polygon(0 5px,100% 0,100% 9px,0 14px);
}

.media-frame{
  position:relative;overflow:hidden;aspect-ratio:16/10;
  background:linear-gradient(135deg,var(--sky-100) 0%,var(--snow) 55%,#FFF3D6 100%);
  border:1px solid rgba(28,36,48,.08);
  clip-path:var(--chamfer);
}
.media-frame--wide{aspect-ratio:21/9;}
.media-frame--tall{aspect-ratio:4/5;}
.media-frame--square{aspect-ratio:1/1;}
.media-frame img,.media-frame svg{width:100%;height:100%;object-fit:cover;}
.media-frame__caption{
  position:absolute;left:0;bottom:0;padding:8px 14px 8px 12px;
  background:rgba(253,253,251,.92);color:var(--ink-500);
  font-size:12px;letter-spacing:.08em;
  clip-path:polygon(0 0,100% 0,calc(100% - 8px) 100%,0 100%);
}

.fret{
  background-image:
    repeating-linear-gradient(45deg,rgba(178,34,34,.16) 0 1px,transparent 1px 14px),
    repeating-linear-gradient(135deg,rgba(11,62,111,.14) 0 1px,transparent 1px 14px);
}

.breadcrumb{padding-block:14px;}
.breadcrumb__list{display:flex;flex-wrap:wrap;align-items:center;gap:8px;font-size:12px;letter-spacing:.12em;color:var(--ink-500);}
.breadcrumb__item{display:inline-flex;align-items:center;gap:8px;}
.breadcrumb__link{
  color:var(--sky-900);
  background-image:linear-gradient(currentColor,currentColor);
  background-repeat:no-repeat;background-position:0 100%;background-size:0 1px;
  transition:background-size 180ms var(--ease);
}
.breadcrumb__link:hover{background-size:100% 1px;}
.breadcrumb__sep{color:rgba(91,102,117,.6);}
.breadcrumb__item[aria-current="page"]{color:var(--ink-900);}

.link-underline{
  color:var(--sky-900);
  background-image:linear-gradient(currentColor,currentColor);
  background-repeat:no-repeat;background-position:0 100%;background-size:0 1px;
  transition:background-size 180ms var(--ease),color 150ms var(--ease);
}
.link-underline:hover{background-size:100% 1px;color:var(--red-700);}

/* ---------- 7 desktop rail ---------- */
@media (min-width:900px){
  html{scroll-padding-top:24px;}
  #main-content{scroll-margin-top:24px;}
  body{padding-left:var(--rail-w);}
  .site-header{
    position:fixed;top:0;left:0;bottom:0;right:auto;
    width:var(--rail-w);
    display:flex;flex-direction:column;
    border-right:1px solid rgba(230,242,255,.18);
    box-shadow:none;
    overflow:hidden;
  }
  .rail__top{
    flex-direction:column;align-items:center;justify-content:flex-start;
    gap:12px;padding:20px 6px 14px;min-height:0;
  }
  .rail__brand{flex-direction:column;gap:8px;text-align:center;}
  .brand-text{align-items:center;}
  .brand-name{font-size:13px;letter-spacing:.06em;}
  .brand-sub{display:none;}
  .rail__toggle{display:none;}
  .version-badge{font-size:9px;padding:3px 7px;letter-spacing:.1em;}
  .version-badge__num{font-size:11px;}

  .site-nav{
    display:block;flex:1 1 auto;min-height:0;overflow-y:auto;
    padding:6px 0 10px;border-top:1px solid rgba(230,242,255,.16);
    scrollbar-width:thin;
  }
  .site-nav__item{border-bottom:0;}
  .site-nav__link{
    position:relative;flex-direction:column;align-items:center;gap:4px;
    padding:9px 4px;font-size:12px;letter-spacing:.06em;text-align:center;
  }
  .site-nav__link::after{
    content:"";position:absolute;left:0;top:50%;width:3px;height:20px;
    background:var(--sky-500);transform:translateY(-50%) scaleY(0);
    transform-origin:center;transition:transform 180ms var(--ease);
  }
  .site-nav__link:hover::after,
  .site-nav__link[aria-current="page"]::after{transform:translateY(-50%) scaleY(1);}
  .site-nav__num{font-size:10px;letter-spacing:.06em;}

  .rail__ticks{
    display:flex;flex-direction:column;align-items:center;gap:2px;
    margin-top:10px;padding-top:10px;
    border-top:1px solid rgba(230,242,255,.14);
  }
  .rail__ticks[hidden]{display:none;}
  .rail__ticks:empty{display:none;}

  .rail__meta{
    display:flex;flex-direction:column;align-items:center;gap:8px;
    padding:12px 6px 16px;border-top:1px solid rgba(230,242,255,.16);
  }
  .rail__member{font-size:11px;letter-spacing:.06em;padding:6px 6px;width:100%;}
  .rail__progress{left:auto;right:0;bottom:auto;top:0;width:3px;height:100%;}
  .rail__progress-fill{
    width:100%;height:calc(var(--sp,0) * 100%);
    background:linear-gradient(180deg,var(--barley-400),var(--red-500));
    transition:height 120ms linear;
  }
}

@media (min-width:900px) and (max-height:700px){
  .rail__top{padding-top:12px;gap:8px;}
  .site-nav__link{padding:6px 4px;}
}

/* ---------- 7b footer layout ---------- */
@media (min-width:720px){
  .footer__grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:clamp(20px,3vw,40px);}
}
@media (min-width:900px){
  .footer__inner{
    display:grid;grid-template-columns:minmax(0,4fr) minmax(0,7fr);
    column-gap:clamp(28px,4vw,64px);align-items:start;
  }
  .footer__lead{border-bottom:0;padding-bottom:0;}
  .footer__grid{padding-top:0;}
  .footer__legal{grid-column:1 / -1;}
}
@media (max-width:389px){
  .brand-sub{display:none;}
  .rail__toggle-label{display:none;}
}

/* ---------- 8 motion ---------- */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto;}
  *,*::before,*::after{
    transition-duration:0ms!important;
    animation-duration:0ms!important;
    animation-iteration-count:1!important;
  }
}