/* ============================================================
   sideline-rhythm-aiyouxi · site.css
   共享外壳 + 排版 + 基础组件
   ============================================================ */

/* ---------- 1 reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body,h1,h2,h3,h4,h5,p,ul,ol,li,figure,blockquote,dl,dd{margin:0}
ul,ol{padding:0;list-style:none}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0;padding:0;cursor:pointer}
img,svg,video{display:block;max-width:100%}
table{border-collapse:collapse;width:100%}
[hidden]{display:none!important}

/* ---------- 2 tokens ---------- */
:root{
  --c-night:#0C1A2B;
  --c-night-deep:#08121D;
  --c-pitch:#123A2B;
  --c-paper:#F2EFE6;
  --c-stack:#D9D3C4;
  --c-ink:#14181C;
  --c-lime:#C8F53C;
  --c-flame:#FF5A2B;
  --c-blue:#2E6E9E;
  --c-moss:#5B7A66;
  --c-timer:#FFC24B;

  --rail:88px;
  --bar-h:58px;
  --gutter:24px;
  --maxw:1280px;
  --radius:2px;

  --font-head:"Archivo Narrow","Arial Narrow","PingFang SC","Noto Sans SC",sans-serif;
  --font-mono:"JetBrains Mono","Roboto Mono",ui-monospace,SFMono-Regular,Menlo,monospace;
  --font-body:"PingFang SC","Noto Sans SC","Microsoft YaHei",sans-serif;

  --fs-1:clamp(40px,6vw,56px);
  --fs-2:clamp(30px,4.2vw,40px);
  --fs-3:clamp(24px,3.2vw,34px);
  --fs-4:clamp(20px,2.4vw,24px);
  --fs-5:clamp(16px,1.4vw,17px);
  --fs-6:14px;
  --fs-7:13px;

  --ease:cubic-bezier(.2,.6,.3,1);
  --grid-line:rgba(242,239,230,.06);
  --grid-ink:rgba(20,24,28,.07);
}

/* ---------- 3 base ---------- */
body{
  background:var(--c-paper);
  color:var(--c-ink);
  font-family:var(--font-body);
  font-size:var(--fs-5);
  line-height:1.85;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
main{display:block}
#main-content{scroll-margin-top:calc(var(--bar-h) + 16px)}

h1,h2,h3,h4{font-family:var(--font-head);font-weight:700;line-height:1.18;letter-spacing:.02em}
h1{font-size:var(--fs-2);letter-spacing:.05em}
h2{font-size:var(--fs-3)}
h3{font-size:var(--fs-4)}
h4{font-size:var(--fs-5);letter-spacing:.08em}
strong,b{font-weight:700}
::selection{background:var(--c-lime);color:var(--c-ink)}

:focus-visible{
  outline:2px solid var(--c-lime);
  outline-offset:2px;
  box-shadow:0 0 0 4px rgba(20,24,28,.55);
}
.site-header :focus-visible,
.site-footer :focus-visible,
.band--night :focus-visible,
.band--pitch :focus-visible{box-shadow:none}

/* ---------- 4 layout ---------- */
.container{width:100%;max-width:var(--maxw);margin:0 auto;padding:0 24px}
.band{padding:64px 0}
.band--paper{background:var(--c-paper);color:var(--c-ink)}
.band--night{background:var(--c-night);color:var(--c-paper)}
.band--pitch{background:var(--c-pitch);color:var(--c-paper)}
.band--grid{
  background-image:
    linear-gradient(var(--grid-line) 1px,transparent 1px),
    linear-gradient(90deg,var(--grid-line) 1px,transparent 1px);
  background-size:24px 24px;
}
.section{padding:48px 0}
.section__head{
  display:flex;flex-wrap:wrap;align-items:flex-end;justify-content:space-between;
  gap:18px;padding-bottom:14px;margin-bottom:28px;border-bottom:1px solid var(--c-ink);
}
.band--night .section__head,
.band--pitch .section__head{border-bottom-color:rgba(242,239,230,.32)}

.grid{display:grid;grid-template-columns:repeat(12,1fr);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-9{grid-column:span 9}
.span-12{grid-column:span 12}

/* ---------- 5 header shell ---------- */
.skip-link{
  position:fixed;left:8px;top:-70px;z-index:200;
  padding:10px 16px;background:var(--c-lime);color:var(--c-ink);
  border:1px solid var(--c-ink);border-radius:var(--radius);
  font-family:var(--font-head);font-weight:700;font-size:14px;letter-spacing:.12em;
  transition:top .16s var(--ease);
}
.skip-link:focus{top:8px}

.site-header{
  position:sticky;top:0;z-index:60;width:100%;
  background:var(--c-night);color:var(--c-paper);
  border-bottom:1px solid rgba(242,239,230,.16);
}
.site-header__bar{
  display:flex;align-items:center;justify-content:space-between;gap:12px;
  min-height:var(--bar-h);padding:0 16px;
}
.brand-mark{
  display:flex;align-items:center;gap:8px;
  color:var(--c-paper);flex:0 0 auto;
}
.brand-mark__tick{width:9px;height:9px;background:var(--c-lime);flex:0 0 auto}
.brand-mark__cn{
  font-family:var(--font-head);font-weight:700;
  font-size:17px;line-height:1;letter-spacing:.14em;
}
.brand-mark__en{
  font-family:var(--font-mono);font-size:9px;line-height:1;
  letter-spacing:.22em;color:rgba(242,239,230,.45);
}
.brand-sync{
  font-family:var(--font-mono);font-size:10px;line-height:1.5;
  letter-spacing:.08em;color:rgba(242,239,230,.5);white-space:nowrap;
}
.nav-toggle{
  display:inline-flex;align-items:center;gap:10px;
  padding:9px 12px;border:1px solid rgba(242,239,230,.3);border-radius:var(--radius);
  color:var(--c-paper);
  font-family:var(--font-head);font-weight:700;font-size:13px;line-height:1;letter-spacing:.14em;
  transition:border-color .18s var(--ease),color .18s var(--ease);
}
.nav-toggle:hover{border-color:var(--c-lime);color:var(--c-lime)}
.nav-toggle__box{position:relative;display:block;width:18px;height:12px;flex:0 0 auto}
.nav-toggle__box::before,
.nav-toggle__box::after{
  content:"";position:absolute;left:0;right:0;height:2px;background:var(--c-lime);
  transition:transform .18s var(--ease),top .18s var(--ease);
}
.nav-toggle__box::before{top:2px}
.nav-toggle__box::after{top:8px}
.nav-toggle[aria-expanded="true"] .nav-toggle__box::before{top:5px;transform:rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__box::after{top:5px;transform:rotate(-45deg)}
.nav-toggle__label{white-space:nowrap}

.site-nav{
  position:fixed;top:var(--bar-h);left:0;right:0;bottom:0;z-index:65;
  padding:16px 16px 32px;overflow-y:auto;
  background:var(--c-night);
  border-top:1px solid rgba(242,239,230,.16);
  transform:translateX(-100%);
  visibility:hidden;
  transition:transform .22s var(--ease),visibility .22s var(--ease);
}
.site-nav[data-open]{transform:translateX(0);visibility:visible}
.site-nav__list{display:flex;flex-direction:column}
.site-nav__item{border-bottom:1px solid rgba(242,239,230,.12)}
.site-nav__link{
  position:relative;display:flex;align-items:center;
  padding:15px 12px;
  font-family:var(--font-head);font-weight:700;
  font-size:16px;line-height:1.2;letter-spacing:.12em;
  color:rgba(242,239,230,.78);
  transition:color .18s var(--ease),background-color .18s var(--ease);
}
.site-nav__link::before{
  content:"";position:absolute;left:0;top:12px;bottom:12px;width:3px;
  background:var(--c-lime);transform:scaleY(0);transform-origin:top;
  transition:transform .18s var(--ease);
}
.site-nav__link:hover,.site-nav__link:focus-visible{color:var(--c-lime)}
.site-nav__link:hover::before,
.site-nav__link[aria-current="page"]::before{transform:scaleY(1)}
.site-nav__link[aria-current="page"]{color:var(--c-lime)}
.site-nav__foot{display:flex;flex-direction:column;gap:12px;margin-top:22px}
.site-nav__foot .btn{width:100%}

.rail-progress{
  position:fixed;left:0;top:0;z-index:70;
  width:3px;height:0;background:var(--c-lime);
  transition:height .12s linear;
}

/* ---------- 6 footer shell ---------- */
.site-footer{
  background:var(--c-pitch);color:rgba(242,239,230,.82);
  border-top:1px solid var(--c-night-deep);
}
.site-footer__top{
  padding:56px 0 44px;
  background-image:
    linear-gradient(var(--grid-line) 1px,transparent 1px),
    linear-gradient(90deg,var(--grid-line) 1px,transparent 1px);
  background-size:24px 24px;
}
.site-footer__grid{display:grid;grid-template-columns:repeat(12,1fr);gap:var(--gutter)}
.site-footer__brand{grid-column:span 4}
.site-footer .brand-mark{
  flex-direction:column;align-items:flex-start;gap:8px;
}
.site-footer .brand-mark__tick{width:12px;height:12px}
.site-footer .brand-mark__cn{font-size:24px;letter-spacing:.16em}
.site-footer .brand-mark__en{font-size:10px;letter-spacing:.24em;color:rgba(242,239,230,.45)}
.brand-mark--footer{padding:0}
.site-footer__sync{
  margin-top:14px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;
  color:var(--c-lime);
}
.footer-stats{display:flex;flex-wrap:wrap;gap:22px;margin-top:22px}
.footer-stats li{display:flex;flex-direction:column;gap:2px}
.footer-stats__num{
  font-family:var(--font-mono);font-weight:600;font-size:26px;line-height:1;
  letter-spacing:-.02em;color:var(--c-paper);font-variant-numeric:tabular-nums;
}
.footer-stats__unit{font-size:12px;letter-spacing:.08em;color:rgba(242,239,230,.55)}

.footer-nav{grid-column:span 8;display:grid;grid-template-columns:repeat(3,1fr);gap:var(--gutter)}
.footer-nav__group{min-width:0}
.footer-nav__title{
  padding-bottom:10px;margin-bottom:14px;
  border-bottom:1px solid rgba(242,239,230,.22);
  font-family:var(--font-head);font-size:12px;letter-spacing:.2em;
  text-transform:uppercase;color:var(--c-lime);
}
.footer-nav__list{display:flex;flex-direction:column;gap:10px}
.footer-nav__link{
  display:inline-block;padding-bottom:2px;
  font-size:14px;color:rgba(242,239,230,.78);
  border-bottom:1px solid transparent;
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.footer-nav__link:hover,.footer-nav__link:focus-visible{
  color:var(--c-lime);border-bottom-color:rgba(200,245,60,.5);
}
.site-footer__contact{
  padding:26px 0;
  background:var(--c-night);
  border-top:1px solid rgba(242,239,230,.14);
}
.site-footer__line{
  font-family:var(--font-mono);font-size:12.5px;line-height:1.9;
  letter-spacing:.02em;color:rgba(242,239,230,.82);
}
.site-footer__note{margin-top:14px;max-width:70em}
.site-footer__legal{background:var(--c-night-deep);padding:16px 0}
.site-footer__legal-inner{
  display:flex;flex-wrap:wrap;gap:12px;justify-content:space-between;align-items:center;
  font-size:12px;letter-spacing:.06em;color:rgba(242,239,230,.5);
}

/* ---------- 7 components ---------- */
.tag{
  display:inline-flex;align-items:baseline;gap:8px;
  padding:4px 8px;border:1px solid currentColor;border-radius:var(--radius);
  font-family:var(--font-head);font-weight:700;
  font-size:11px;line-height:1.4;letter-spacing:.14em;text-transform:uppercase;
}
.tag__cn{
  font-family:var(--font-body);font-weight:400;font-size:12px;
  letter-spacing:.08em;opacity:.78;
}
.tag--lime{color:var(--c-lime);border-color:var(--c-lime)}
.tag--flame{color:#FFF3EE;background:var(--c-flame);border-color:var(--c-flame)}
.tag--blue{color:var(--c-blue);border-color:var(--c-blue)}

.paper-card{
  position:relative;
  padding:22px;
  background:var(--c-paper);color:var(--c-ink);
  border:1px solid var(--c-ink);border-radius:var(--radius);
  box-shadow:6px 6px 0 var(--c-stack);
  transition:transform .18s var(--ease),box-shadow .18s var(--ease);
}
.paper-card:hover{transform:translateY(-4px);box-shadow:6px 6px 0 var(--c-stack),0 0 0 1px rgba(20,24,28,.08)}

.stat{display:flex;flex-direction:column;gap:4px}
.stat__num{
  font-family:var(--font-mono);font-weight:600;
  font-size:clamp(48px,7vw,96px);line-height:.98;letter-spacing:-.02em;
  font-variant-numeric:tabular-nums;
}
.stat__unit{font-size:var(--fs-7);letter-spacing:.08em;color:var(--c-moss)}
.band--night .stat__num{color:var(--c-lime)}
.band--pitch .stat__num{color:var(--c-timer)}
.band--night .stat__unit,
.band--pitch .stat__unit{color:rgba(242,239,230,.62)}

.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:13px 22px;
  background:var(--c-paper);color:var(--c-ink);
  border:1px solid var(--c-ink);border-radius:var(--radius);
  font-family:var(--font-head);font-weight:700;
  font-size:14px;line-height:1.2;letter-spacing:.14em;text-transform:uppercase;
  transition:background-color .18s var(--ease),color .18s var(--ease),transform .18s var(--ease);
}
.btn:hover{transform:translateY(-2px)}
.btn--lime{background:var(--c-lime);border-color:var(--c-ink);color:var(--c-ink)}
.btn--lime:hover{background:#D9FF62}
.btn--flame{background:var(--c-flame);border-color:var(--c-flame);color:#FFF3EE}
.btn--flame:hover{background:#FF7448}
.btn--ghost{background:transparent;border-color:currentColor;color:inherit}
.btn--ghost:hover{background:rgba(200,245,60,.12)}

.breadcrumb{
  display:flex;flex-wrap:wrap;align-items:center;gap:10px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--c-moss);
}
.breadcrumb__item{display:inline-flex;align-items:center;gap:10px}
.breadcrumb__item::after{content:"/";color:var(--c-stack)}
.breadcrumb__item:last-child::after{content:""}
.breadcrumb a:hover,.breadcrumb a:focus-visible{color:var(--c-blue)}
.breadcrumb__current{color:var(--c-ink)}
.band--night .breadcrumb,.band--pitch .breadcrumb{color:rgba(242,239,230,.6)}
.band--night .breadcrumb__current,
.band--pitch .breadcrumb__current{color:var(--c-paper)}

.note{
  padding-left:12px;
  border-left:2px solid var(--c-stack);
  font-size:var(--fs-7);line-height:1.7;letter-spacing:.01em;color:var(--c-moss);
}
.note--dark{color:rgba(242,239,230,.58);border-left-color:rgba(200,245,60,.42)}

.rule{
  height:1px;margin:0;border:0;background:var(--c-ink);
  box-shadow:0 8px 0 -7px var(--c-stack);
}
.band--night .rule,.band--pitch .rule{background:rgba(242,239,230,.3);box-shadow:none}

.tick-list{display:flex;flex-direction:column;gap:10px}
.tick-list li{position:relative;padding-left:20px;font-size:15px;line-height:1.75}
.tick-list li::before{
  content:"";position:absolute;left:0;top:.72em;
  width:9px;height:3px;background:var(--c-ink);
}
.band--night .tick-list li::before,
.band--pitch .tick-list li::before{background:var(--c-lime)}

.media-frame{
  position:relative;display:block;overflow:hidden;
  aspect-ratio:16/9;min-height:160px;
  background:var(--c-night);
  border:1px solid var(--c-ink);border-radius:var(--radius);
}
.media-frame__img{width:100%;height:100%;object-fit:cover}
.media-frame::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background-image:
    linear-gradient(var(--grid-line) 1px,transparent 1px),
    linear-gradient(90deg,var(--grid-line) 1px,transparent 1px);
  background-size:24px 24px;
}
.media-frame--wide{aspect-ratio:21/9}
.media-frame--portrait{aspect-ratio:4/5}
.media-frame--square{aspect-ratio:1/1}
.media-frame__cap{
  position:absolute;left:0;right:0;bottom:0;z-index:2;
  padding:10px 14px;
  background:rgba(12,26,43,.86);color:var(--c-paper);
  border-top:1px solid rgba(200,245,60,.45);
  font-size:12px;line-height:1.6;letter-spacing:.06em;
}
.media-frame--offset{margin-left:calc(-1 * var(--gutter))}

.data-table{
  border:1px solid var(--c-ink);
  font-size:var(--fs-6);line-height:1.7;
}
.data-table caption{
  caption-side:top;text-align:left;padding-bottom:8px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--c-moss);
}
.data-table th,.data-table td{
  padding:10px 12px;text-align:left;vertical-align:top;
  border:1px solid var(--c-ink);
}
.data-table thead th{
  background:var(--c-night);color:var(--c-paper);
  font-family:var(--font-head);font-size:12px;letter-spacing:.1em;text-transform:uppercase;
}
.data-table tbody tr:nth-child(even){background:var(--c-stack)}
.data-table .num{
  font-family:var(--font-mono);letter-spacing:-.02em;white-space:nowrap;
  font-variant-numeric:tabular-nums;
}

.timeline{position:relative;padding-left:26px}
.timeline::before{
  content:"";position:absolute;left:5px;top:8px;bottom:8px;width:1px;background:var(--c-stack);
}
.timeline__item{position:relative;padding-bottom:22px}
.timeline__item::before{
  content:"";position:absolute;left:-26px;top:9px;
  width:11px;height:11px;background:var(--c-paper);border:1px solid var(--c-ink);
}
.timeline__item--now::before{background:var(--c-lime)}
.timeline__label{
  display:block;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--c-moss);
}
.band--night .timeline::before,.band--pitch .timeline::before{background:rgba(242,239,230,.24)}
.band--night .timeline__item::before,
.band--pitch .timeline__item::before{background:var(--c-night);border-color:rgba(242,239,230,.6)}
.band--night .timeline__item--now::before,
.band--pitch .timeline__item--now::before{background:var(--c-lime);border-color:var(--c-lime)}
.band--night .timeline__label,
.band--pitch .timeline__label{color:rgba(242,239,230,.62)}

.prose{max-width:42em}
.prose p{margin-bottom:1.1em}
.prose h2{margin:1.6em 0 .6em;font-size:var(--fs-3)}
.prose h3{margin:1.4em 0 .5em;font-size:var(--fs-4)}
.prose ul{margin:0 0 1.1em}
.prose li{position:relative;padding-left:18px;margin-bottom:.4em}
.prose li::before{content:"";position:absolute;left:0;top:.78em;width:8px;height:2px;background:var(--c-moss)}
.prose a{color:var(--c-blue);border-bottom:1px solid rgba(46,110,158,.45)}
.prose a:hover,.prose a:focus-visible{border-bottom-color:var(--c-blue)}
.band--night .prose a,.band--pitch .prose a{color:var(--c-lime);border-bottom-color:rgba(200,245,60,.45)}

/* ---------- 8 motion ---------- */
html.js [data-reveal]{
  opacity:0;transform:translateY(4px);
  transition:opacity .2s var(--ease),transform .2s var(--ease);
}
html.js [data-reveal].is-revealed{opacity:1;transform:none}

/* ---------- 9 desktop rail ---------- */
@media (min-width:900px){
  body{padding-left:var(--rail)}
  .skip-link{left:calc(var(--rail) + 10px)}

  .site-header{
    position:fixed;top:0;left:0;bottom:0;width:var(--rail);
    display:flex;flex-direction:column;align-items:center;
    padding:20px 0 14px;
    border-bottom:0;border-right:1px solid var(--c-night-deep);
    overflow-y:auto;overflow-x:hidden;scrollbar-width:none;
    background-image:
      linear-gradient(var(--grid-line) 1px,transparent 1px),
      linear-gradient(90deg,var(--grid-line) 1px,transparent 1px);
    background-size:24px 24px;
  }
  .site-header::-webkit-scrollbar{width:0;height:0}

  .site-header__bar{
    flex-direction:column;justify-content:flex-start;align-items:center;
    gap:14px;width:100%;min-height:0;
    padding:0 0 16px;
    border-bottom:1px solid rgba(242,239,230,.14);
  }
  .brand-mark{flex-direction:column;gap:10px}
  .site-header .brand-mark__cn{
    writing-mode:vertical-rl;font-size:17px;letter-spacing:.18em;
  }
  .site-header .brand-mark__en{display:none}
  .brand-sync{
    display:block;white-space:normal;
    writing-mode:vertical-rl;max-height:108px;
    font-size:10px;line-height:1.5;letter-spacing:.12em;
    text-align:left;
  }
  .nav-toggle{display:none}

  .site-nav{
    position:static;transform:none;visibility:visible;
    flex:1 1 auto;width:100%;margin-top:16px;
    padding:0;overflow:visible;background:transparent;border-top:0;
  }
  .site-nav__list{align-items:center;gap:4px}
  .site-nav__item{border-bottom:0}
  .site-nav__link{
    writing-mode:vertical-rl;text-orientation:upright;
    justify-content:center;
    padding:10px 6px;
    font-size:14px;letter-spacing:.14em;
  }
  .site-nav__link::before{left:-6px;top:8px;bottom:8px;right:auto;width:3px}
  .site-nav__link[aria-current="page"]{background:rgba(200,245,60,.06)}

  .site-nav__foot{
    margin-top:auto;width:100%;align-items:center;
    padding-top:16px;border-top:1px solid rgba(242,239,230,.14);
  }
  .site-nav__foot .btn{
    width:auto;
    writing-mode:vertical-rl;text-orientation:upright;
    padding:16px 11px;font-size:12.5px;letter-spacing:.16em;
  }
  .rail-progress{top:0}
}

@media (min-width:900px) and (max-height:960px){
  .site-header{padding-top:14px}
  .brand-sync{display:none}
  .brand-mark__cn{font-size:15px}
  .site-nav{margin-top:10px}
  .site-nav__link{font-size:13px;padding:8px 6px;letter-spacing:.12em}
  .site-nav__foot .btn{font-size:12px;padding:12px 9px}
}

/* ---------- 10 tablet / mobile ---------- */
@media (max-width:1099px){
  .site-footer__brand{grid-column:span 12}
  .footer-nav{grid-column:span 12}
}
@media (max-width:899px){
  .site-footer__top{padding:44px 0 36px}
  .footer-nav{grid-template-columns:repeat(2,1fr)}
  .media-frame--offset{margin-left:0}
}
@media (max-width:1023px){
  .span-3,.span-4,.span-5{grid-column:span 6}
  .span-7,.span-8,.span-9{grid-column:span 12}
}
@media (max-width:639px){
  .container{padding:0 18px}
  .band{padding:44px 0}
  .section{padding:34px 0}
  .brand-sync{display:none}
  .grid{grid-template-columns:repeat(6,1fr);gap:16px}
  .span-3,.span-4,.span-5,.span-6,
  .span-7,.span-8,.span-9,.span-12{grid-column:span 6}
  .footer-nav{grid-template-columns:1fr}
  .media-frame{aspect-ratio:4/3}
}
@media (max-width:899px){
  html.nav-open,
  html.nav-open body{overflow:hidden}
}

/* ---------- 11 reduced motion ---------- */
@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;
  }
  html.js [data-reveal]{opacity:1;transform:none}
}