/* ============================================================
   28圈主站 · 共享外壳样式 /assets/site.css
   深靛夜底 + 奶油档案纸面板 + 霓虹青/珊瑚橙/暖金状态色
   ============================================================ */

/* ---------- 1. 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,li,dl,dd,figure,blockquote{margin:0;padding:0}
ul,ol{list-style:none}
img,svg,video{max-width:100%;height:auto;display:block}
button,input,select,textarea{font:inherit;color:inherit}
table{border-collapse:collapse;border-spacing:0}
main{display:block}
[hidden]{display:none!important}
a{color:inherit}

/* ---------- 2. 变量 ---------- */
:root{
  --ink-night:#0B1020;
  --ink-slate:#12182B;
  --paper:#F2EAE0;
  --paper-ink:#2A211C;
  --cyan:#4FE3D1;
  --coral:#FF7A4D;
  --gold:#E8B85C;
  --mist:#7C89AD;
  --jade:#1F8C7E;
  --white:#F5F7FF;

  --rail:72px;
  --header-h:60px;

  --line:1px solid rgba(124,137,173,.24);
  --line-strong:1px solid rgba(124,137,173,.42);
  --line-paper:1px solid rgba(42,33,28,.20);

  --radius:2px;
  --shadow-in:inset 0 1px 0 rgba(245,247,255,.045);

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

  --ease:cubic-bezier(.2,.7,.3,1);
}

/* ---------- 3. 基础 ---------- */
body{
  background:var(--ink-night);
  color:var(--white);
  font-family:var(--font-body);
  font-size:16px;
  font-weight:400;
  line-height:1.75;
  padding-top:var(--header-h);
  -webkit-font-smoothing:antialiased;
}
body.has-overlay-hero{padding-top:0}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:800;letter-spacing:-.01em;line-height:1.3}
p{max-width:44em}

:focus-visible{outline:2px solid var(--cyan);outline-offset:2px;border-radius:1px}
::selection{background:rgba(79,227,209,.28);color:var(--white)}

.visually-hidden{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.hairline{height:1px;background:rgba(124,137,173,.28);border:0;margin:0}

/* ---------- 4. 跳转与进度 ---------- */
.skip-link{
  position:fixed;top:-72px;left:16px;z-index:200;
  display:inline-block;padding:10px 16px;border-radius:var(--radius);
  background:var(--cyan);color:#06201C;font-size:14px;font-weight:600;text-decoration:none;
  transition:top .16s var(--ease);
}
.skip-link:focus{top:14px}

.progress{position:fixed;top:0;left:0;right:0;height:2px;z-index:120;pointer-events:none}
.progress__bar{display:block;height:100%;width:0;background:linear-gradient(90deg,var(--cyan),var(--gold));transition:width .12s linear}

/* ---------- 5. 左侧数字索引轨 ---------- */
.site-rail{display:none}

/* ---------- 6. 页头 ---------- */
.site-header{
  position:fixed;top:0;left:0;right:0;z-index:80;
  height:var(--header-h);
  background:transparent;
  border-bottom:1px solid transparent;
  transition:background-color .2s linear,border-color .2s linear;
}
.site-header[data-scrolled]{
  background:#12182B;
  border-bottom-color:var(--cyan);
  box-shadow:0 1px 0 rgba(79,227,209,.18);
}
.site-header__bar{
  height:100%;max-width:1440px;margin:0 auto;
  padding:0 16px;display:flex;align-items:center;gap:16px;
}

/* 品牌 */
.brand{
  display:flex;align-items:baseline;gap:10px;
  text-decoration:none;color:var(--white);white-space:nowrap;
}
.brand__mark{position:relative;font-family:var(--font-display);font-size:21px;font-weight:800;letter-spacing:-.01em;padding-left:14px}
.brand__mark::before{content:"";position:absolute;left:0;top:.34em;width:7px;height:7px;background:var(--cyan)}
.brand__sub{font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;color:var(--mist)}
.brand--stacked{flex-direction:column;align-items:flex-start;gap:6px;margin-bottom:14px;white-space:normal}

/* 主导航 */
.site-nav{display:flex;align-items:center;gap:20px;margin-left:auto}
.site-nav__list{display:flex;align-items:center;gap:2px}
.site-nav__link{
  position:relative;display:block;padding:10px 11px;
  color:var(--mist);font-size:15px;line-height:1.4;text-decoration:none;
  transition:color .16s linear;
}
.site-nav__link::after{
  content:"";position:absolute;left:11px;right:11px;bottom:5px;height:1px;
  background:var(--cyan);transform:scaleX(0);transform-origin:left;
  transition:transform .16s var(--ease);
}
.site-nav__link:hover{color:var(--white)}
.site-nav__link:hover::after{transform:scaleX(1)}
.site-nav__link[aria-current="page"]{color:var(--cyan)}
.site-nav__link[aria-current="page"]::after{transform:scaleX(1);background:var(--gold)}

.site-nav__side{display:flex;align-items:center;gap:12px}
.search-entry{
  font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;
  color:var(--mist);text-decoration:none;padding:7px 12px;
  border:1px solid rgba(124,137,173,.34);border-radius:var(--radius);
  transition:border-color .16s linear,color .16s linear;
}
.search-entry:hover{border-color:var(--cyan);color:var(--white)}
.utility-link{
  font-size:13px;color:var(--mist);text-decoration:none;padding:8px 4px;
  background-image:linear-gradient(var(--cyan),var(--cyan));
  background-size:0% 1px;background-repeat:no-repeat;background-position:0 100%;
  transition:color .16s linear,background-size .16s var(--ease);
}
.utility-link:hover{color:var(--white);background-size:100% 1px}

/* 按钮 */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  font-family:var(--font-body);font-size:14px;font-weight:600;line-height:1.3;
  padding:9px 16px;border:1px solid transparent;border-radius:var(--radius);
  text-decoration:none;white-space:nowrap;
  transition:background-color .16s linear,color .16s linear,border-color .16s linear;
}
.btn--accent{background:var(--cyan);border-color:var(--cyan);color:#06201C}
.btn--accent:hover{background:#7BF0E2;border-color:#7BF0E2;color:#052A24}
.btn--ghost{background:transparent;border-color:rgba(124,137,173,.42);color:var(--white)}
.btn--ghost:hover{border-color:var(--cyan);color:var(--cyan)}
.btn--gold{background:var(--gold);border-color:var(--gold);color:var(--paper-ink)}
.btn--gold:hover{background:#F2CB7C;border-color:#F2CB7C}

/* 移动菜单按钮 */
.nav-toggle{
  display:none;margin-left:auto;align-items:center;gap:9px;
  background:transparent;border:1px solid rgba(124,137,173,.42);border-radius:var(--radius);
  color:var(--white);font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;
  padding:8px 12px;cursor:pointer;
  transition:border-color .16s linear,color .16s linear;
}
.nav-toggle:hover{border-color:var(--cyan);color:var(--cyan)}
.nav-toggle__bars{position:relative;display:block;width:16px;height:8px}
.nav-toggle__bars::before,.nav-toggle__bars::after{
  content:"";position:absolute;left:0;right:0;height:1px;background:currentColor;
  transition:transform .18s var(--ease),top .18s var(--ease);
}
.nav-toggle__bars::before{top:0}
.nav-toggle__bars::after{top:7px}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before{top:3px;transform:rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after{top:3px;transform:rotate(-45deg)}
.nav-toggle__text{line-height:1}

/* ---------- 7. 移动端导航面板 ---------- */
@media (max-width:1119px){
  .nav-toggle{display:inline-flex}
  .site-nav{
    position:fixed;left:0;right:0;top:var(--header-h);
    max-height:calc(100vh - var(--header-h));
    overflow-y:auto;-webkit-overflow-scrolling:touch;
    display:none;flex-direction:column;align-items:stretch;gap:0;
    margin-left:0;padding:6px 0 26px;
    background:#0B1020;
    border-top:var(--line);
    border-bottom:1px solid var(--cyan);
  }
  .site-nav[data-open]{display:flex}
  .site-nav__list{flex-direction:column;align-items:stretch;gap:0}
  .site-nav__link{padding:15px 20px;font-size:17px;border-bottom:var(--line)}
  .site-nav__link::after{display:none}
  .site-nav__link[aria-current="page"]{background:rgba(79,227,209,.08)}
  .site-nav__side{flex-direction:column;align-items:stretch;gap:12px;padding:20px}
  .search-entry,.utility-link{text-align:center;padding:12px 14px}
  .site-nav__side .btn{width:100%;padding:12px 16px}
}

/* ---------- 8. 容器 / 章节 / 网格 ---------- */
.container{width:100%;max-width:1440px;margin:0 auto;padding:0 16px}
.section{padding:56px 0}
.section--tight{padding:32px 0}
.section__head{
  display:flex;align-items:flex-end;justify-content:space-between;gap:20px;flex-wrap:wrap;
  padding-bottom:14px;margin-bottom:26px;border-bottom:var(--line-strong);
}
.section__title{font-size:28px}
.eyebrow{font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;color:var(--cyan);display:block;margin-bottom:8px}
.lede{font-size:17px;line-height:1.75;color:var(--mist);max-width:38em}

.grid{display:grid;gap:24px}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid--4{grid-template-columns:repeat(4,minmax(0,1fr))}
.grid--asym{grid-template-columns:minmax(0,1.7fr) minmax(0,1fr) minmax(0,1fr)}

/* ---------- 9. 面板 ---------- */
.panel{background:var(--ink-slate);border:var(--line);box-shadow:var(--shadow-in);padding:22px;border-radius:var(--radius)}
.panel--flush{padding:0}
.panel--paper{background:var(--paper);color:var(--paper-ink);border:var(--line-paper);box-shadow:none}
.panel__head{
  display:flex;align-items:baseline;justify-content:space-between;gap:12px;
  padding-bottom:10px;margin-bottom:14px;border-bottom:var(--line);
}
.panel--paper .panel__head{border-bottom:var(--line-paper)}
.panel__title{font-size:17px;font-weight:700}

/* ---------- 10. 数字与状态色 ---------- */
.num{font-family:var(--font-mono);font-variant-numeric:tabular-nums;letter-spacing:.08em;font-weight:700;line-height:1}
.num--hero{font-size:96px}
.num--xl{font-size:64px}
.num--lg{font-size:40px}
.num--md{font-size:28px;line-height:1.2}
.num--sm{font-size:17px;font-weight:500}

.t-cyan{color:var(--cyan)}
.t-gold{color:var(--gold)}
.t-coral{color:var(--coral)}
.t-mist{color:var(--mist)}
.t-white{color:var(--white)}
.mark-cold{color:var(--jade)}

.tag{
  display:inline-flex;align-items:center;gap:6px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;line-height:1.4;
  padding:3px 8px;border:1px solid rgba(124,137,173,.42);border-radius:var(--radius);color:var(--mist);
}
.tag--cyan{color:var(--cyan);border-color:rgba(79,227,209,.45)}
.tag--coral{color:var(--coral);border-color:rgba(255,122,77,.45)}
.tag--gold{color:var(--gold);border-color:rgba(232,184,92,.45)}

/* ---------- 11. 正文 / 表格 / 旁注 ---------- */
.prose{font-size:15px;line-height:1.75;max-width:36em;color:inherit}
.prose>*+*{margin-top:16px}
.prose h3{font-size:21px;margin-top:28px}

.data-table{width:100%;font-variant-numeric:tabular-nums}
.data-table th,.data-table td{padding:10px 12px;text-align:left;border-bottom:var(--line)}
.data-table th{font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;font-weight:500;color:var(--mist)}
.data-table td{font-family:var(--font-mono);font-size:14px;letter-spacing:.08em;color:var(--white)}
.data-table tbody tr{transition:background-color .16s linear}
.data-table tbody tr:hover{background:rgba(79,227,209,.06)}
.data-table tbody tr:hover td{border-bottom-color:rgba(79,227,209,.5)}

.note{border-left:2px solid var(--gold);padding:6px 0 6px 14px;font-size:13px;line-height:1.8;color:var(--mist)}
.note__num{display:block;font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;color:var(--gold);margin-bottom:4px}

/* ---------- 12. 面包屑 ---------- */
.breadcrumb{display:flex;flex-wrap:wrap;align-items:center;gap:8px;padding:22px 0 0;font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--mist)}
.breadcrumb__link{color:var(--mist);text-decoration:none;transition:color .16s linear}
.breadcrumb__link:hover{color:var(--cyan)}
.breadcrumb__sep{color:rgba(124,137,173,.6)}
.breadcrumb__current{color:var(--white)}

/* ---------- 13. 图片容器 ---------- */
.media{
  position:relative;display:block;width:100%;overflow:hidden;
  background:linear-gradient(135deg,#0E1426 0%,#161F38 60%,#101728 100%);
  border:var(--line);border-radius:var(--radius);
}
.media>img,.media>svg,.media>video{width:100%;height:100%;object-fit:cover}
.media--21x9{aspect-ratio:21/9}
.media--16x9{aspect-ratio:16/9}
.media--4x3{aspect-ratio:4/3}
.media--1x1{aspect-ratio:1/1}
.media__caption{font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;color:var(--mist);margin-top:8px}

/* ---------- 14. 折叠面板 ---------- */
.fold__trigger{
  display:inline-flex;align-items:center;gap:8px;margin-top:16px;
  background:transparent;border:1px solid rgba(124,137,173,.42);border-radius:var(--radius);
  color:var(--white);font-family:var(--font-mono);font-size:12px;letter-spacing:.14em;
  padding:9px 14px;cursor:pointer;
  transition:border-color .16s linear,color .16s linear;
}
.fold__trigger:hover{border-color:var(--cyan);color:var(--cyan)}
.fold[data-open] .fold__trigger{border-color:var(--gold);color:var(--gold)}

/* ---------- 15. 页脚 ---------- */
.site-footer{
  margin-top:88px;
  background:var(--ink-slate);
  border-top:var(--line-strong);
  color:var(--mist);
  position:relative;
}
.site-footer::before{
  content:"";position:absolute;top:0;left:0;right:0;height:2px;
  background:linear-gradient(90deg,var(--cyan),rgba(79,227,209,0) 62%);
}
.site-footer__inner{max-width:1440px;margin:0 auto;padding:54px 16px 26px}
.site-footer__grid{display:grid;gap:40px 32px;grid-template-columns:1.5fr 1fr 1.5fr 1.5fr}

.footer-col__title{
  font-family:var(--font-mono);font-size:12px;font-weight:500;letter-spacing:.14em;
  color:var(--white);padding-bottom:12px;margin-bottom:14px;border-bottom:var(--line);
}
.footer-links li{margin-bottom:2px}
.footer-links a{
  display:inline-block;padding:4px 0;font-size:14px;color:var(--mist);text-decoration:none;
  background-image:linear-gradient(var(--cyan),var(--cyan));
  background-size:0% 1px;background-repeat:no-repeat;background-position:0 100%;
  transition:color .16s linear,background-size .16s var(--ease);
}
.footer-links a:hover{color:var(--white);background-size:100% 1px}

.footer-note{font-size:13px;line-height:1.8;color:var(--mist);max-width:34em;margin-bottom:12px}
.footer-meta{font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;line-height:1.95;color:var(--mist);word-break:break-word}

.site-footer__base{
  display:flex;flex-wrap:wrap;justify-content:space-between;gap:12px;
  margin-top:42px;padding-top:18px;border-top:var(--line);
}
.footer-legal{font-family:var(--font-mono);font-size:12px;letter-spacing:.08em;line-height:1.9;color:var(--mist);max-width:60em}

/* ---------- 16. 断点 ---------- */
@media (max-width:1023px){
  .grid--3,.grid--4,.grid--asym{grid-template-columns:repeat(2,minmax(0,1fr))}
  .site-footer__grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .section{padding:44px 0}
  .section__title{font-size:24px}
  .num--hero{font-size:64px}
  .num--xl{font-size:48px}
}
@media (max-width:639px){
  .grid--2,.grid--3,.grid--4,.grid--asym{grid-template-columns:minmax(0,1fr)}
  .site-footer__grid{grid-template-columns:minmax(0,1fr);gap:32px}
  .container,.site-header__bar,.site-footer__inner{padding-left:16px;padding-right:16px}
  .section__title{font-size:21px}
  .num--hero{font-size:44px}
  .num--xl{font-size:34px}
  .num--lg{font-size:28px}
  .panel{padding:18px}
  .site-footer{margin-top:64px}
}
@media (max-width:479px){
  .brand__sub{display:none}
}

/* ---------- 17. 桌面：索引轨 + 偏移 ---------- */
@media (min-width:1180px){
  :root{--header-h:66px}
  body{padding-left:var(--rail)}
  .site-header{left:var(--rail)}
  .progress{left:var(--rail)}
  .site-rail{
    display:flex;position:fixed;top:0;left:0;width:var(--rail);height:100vh;z-index:90;
    flex-direction:column;justify-content:center;padding:0 0 40px;
    background:#0B1020;
    border-right:var(--line);
  }
  .site-rail__list{display:flex;flex-direction:column;gap:2px}
  .site-rail__link{
    display:flex;align-items:center;gap:10px;
    padding:9px 10px 9px 18px;
    color:var(--mist);text-decoration:none;
    border-left:2px solid transparent;
    transition:color .16s linear,border-color .16s linear,background-color .16s linear;
  }
  .site-rail__num{font-family:var(--font-mono);font-size:13px;letter-spacing:.08em;font-variant-numeric:tabular-nums}
  .site-rail__label{
    font-size:13px;white-space:nowrap;opacity:0;transform:translateX(-4px);
    transition:opacity .16s linear,transform .16s var(--ease);
  }
  .site-rail__item:hover .site-rail__label,
  .site-rail__link:focus-visible .site-rail__label{opacity:1;transform:none}
  .site-rail__link:hover{color:var(--white);border-left-color:var(--cyan);background:rgba(79,227,209,.05)}
  .site-rail__link[aria-current="page"]{color:var(--gold);border-left-color:var(--gold)}
  .site-rail__link[aria-current="page"] .site-rail__num{font-weight:700}
  .site-rail__meta{
    position:absolute;bottom:20px;left:0;width:var(--rail);
    text-align:center;font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;color:rgba(124,137,173,.7);
  }
}

/* ---------- 18. 动效偏好 ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms!important;
    animation-iteration-count:1!important;
    transition-duration:.001ms!important;
    transition-delay:0ms!important;
  }
  .progress__bar{transition:none}
  .site-nav__link::after{transform:scaleX(0)}
  .site-nav__link:hover::after,.site-nav__link[aria-current="page"]::after{transform:scaleX(1)}
}