*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:24px}
body,h1,h2,h3,h4,p,ul,ol,figure,blockquote{margin:0}
ul,ol{padding:0;list-style:none}
img,svg,video{max-width:100%;height:auto}
button{font:inherit;color:inherit}
a{color:inherit}
:focus-visible{outline:3px solid #35C5C0;outline-offset:3px}

:root{
  --ink:#0B1B2B;
  --ink-2:#12283D;
  --ink-3:#0E2135;
  --stone:#5E6A72;
  --bone:#F1EBDD;
  --amber:#D99A2B;
  --cyan:#35C5C0;
  --green:#3FAF8A;
  --orange:#E07A3F;
  --clay:#B56A4C;
  --moss:#6E7F5A;
  --white:#FFFFFF;
  --font-title:'Noto Sans SC','Source Han Sans SC','Microsoft YaHei',sans-serif;
  --font-body:'Noto Sans SC','Source Han Sans SC','PingFang SC',sans-serif;
  --font-mono:'JetBrains Mono','IBM Plex Mono','SFMono-Regular',monospace;
  --line:rgba(94,106,114,.45);
  --line-strong:rgba(241,235,221,.18);
  --shell:1200px;
  --gutter:clamp(16px,4vw,48px);
  --ease:cubic-bezier(.2,.7,.2,1);
  --shadow-hard:6px 6px 0 rgba(0,0,0,.55);
  --shadow-soft:2px 2px 0 rgba(0,0,0,.35);
}

body{
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.8;
  color:var(--bone);
  background-color:var(--ink);
  background-image:
    linear-gradient(to right,rgba(94,106,114,.14) 1px,transparent 1px),
    linear-gradient(to bottom,rgba(94,106,114,.14) 1px,transparent 1px);
  background-size:72px 72px;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4{font-family:var(--font-title);font-weight:900;line-height:1.15;letter-spacing:-.015em}
.num,.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums;letter-spacing:.02em}

.shell{width:100%;max-width:var(--shell);margin-inline:auto;padding-inline:var(--gutter)}

/* ---------- skip link ---------- */
.skip-link{
  position:absolute;left:-9999px;top:0;z-index:900;
  background:var(--amber);color:var(--ink);
  padding:12px 20px;font-weight:800;text-decoration:none;
}
.skip-link:focus{left:12px;top:12px}

/* ---------- header ---------- */
.site-header{
  position:relative;z-index:80;
  background:linear-gradient(180deg,rgba(11,27,43,.99),rgba(11,27,43,.93));
  border-bottom:1px solid var(--line-strong);
}
.status-strip{background:var(--amber);color:var(--ink);border-bottom:1px solid rgba(0,0,0,.3)}
.status-strip__inner{
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  min-height:34px;padding-block:6px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;
}
.status-strip__flag{display:flex;align-items:center;gap:8px;font-weight:700}
.status-strip__dot{
  width:7px;height:7px;border-radius:50%;background:var(--ink);
  box-shadow:0 0 0 3px rgba(11,27,43,.18);
  animation:strip-pulse 2.6s var(--ease) infinite;
}
.status-strip__meta{color:rgba(11,27,43,.76)}
@keyframes strip-pulse{0%,100%{opacity:1}50%{opacity:.35}}

.masthead{
  display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:24px;
  padding-block:clamp(18px,2.6vw,30px) clamp(14px,2vw,22px);
}
.masthead__meta{
  justify-self:start;align-self:end;
  font-family:var(--font-mono);font-size:11px;line-height:1.9;
  letter-spacing:.14em;color:var(--stone);
}
.masthead__meta-sub{
  display:block;font-family:var(--font-body);font-size:11px;
  letter-spacing:.22em;color:rgba(94,106,114,.9);
}
.brand{justify-self:center;text-align:center;text-decoration:none;display:block}
.brand__mark{
  display:block;font-family:var(--font-title);font-weight:900;
  font-size:clamp(30px,4.6vw,48px);line-height:1;
  letter-spacing:.16em;padding-left:.16em;color:var(--bone);
}
.brand__mark-accent{color:var(--amber)}
.brand__sub{
  display:block;margin-top:10px;
  font-family:var(--font-mono);font-size:11px;
  letter-spacing:.34em;padding-left:.34em;color:var(--stone);
}
.masthead__cta{
  justify-self:end;align-self:end;
  display:inline-flex;align-items:center;gap:8px;
  padding:10px 16px;border:2px solid var(--amber);
  color:var(--amber);background:transparent;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;
  text-decoration:none;
  transition:background-color .18s var(--ease),color .18s var(--ease),transform .18s var(--ease);
}
.masthead__cta:hover{background:var(--amber);color:var(--ink);transform:translateY(-2px)}

.nav-bar{background:rgba(18,40,61,.68);border-top:1px solid var(--line);border-bottom:1px solid var(--line-strong)}
.nav-bar__inner{position:relative;display:flex;align-items:center;justify-content:center;min-height:56px}
.site-nav__list{display:flex;align-items:center;gap:clamp(8px,2vw,28px)}
.site-nav__link{
  display:inline-block;padding:16px 2px;
  font-size:15px;font-weight:500;text-decoration:none;
  color:rgba(241,235,221,.8);
  border-bottom:2px solid transparent;
  transition:color .16s var(--ease),border-color .16s var(--ease);
}
.site-nav__link::before{
  content:attr(data-index);
  font-family:var(--font-mono);font-size:10px;letter-spacing:.06em;
  color:var(--stone);margin-right:7px;
  transition:color .16s var(--ease);
}
.site-nav__link:hover{color:var(--bone);border-bottom-color:var(--cyan)}
.site-nav__link:hover::before{color:var(--cyan)}
.site-nav__link[aria-current="page"]{color:var(--bone);font-weight:800;border-bottom-color:var(--amber)}
.site-nav__link[aria-current="page"]::before{color:var(--amber)}
.nav-bar__quick{
  position:absolute;right:0;top:50%;transform:translateY(-50%);
  padding:7px 14px;border:1px solid rgba(53,197,192,.55);
  color:var(--cyan);text-decoration:none;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;
  transition:background-color .16s var(--ease),color .16s var(--ease);
}
.nav-bar__quick:hover{background:var(--cyan);color:var(--ink)}
.nav-toggle{
  display:none;align-items:center;gap:10px;
  background:transparent;border:1px solid var(--line);
  padding:8px 12px;cursor:pointer;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;color:var(--bone);
}
.nav-toggle__bars{display:inline-flex;flex-direction:column;gap:4px;width:18px}
.nav-toggle__bars span{display:block;height:2px;width:100%;background:var(--amber);transition:transform .18s var(--ease),opacity .18s var(--ease)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(1){transform:translateY(6px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:nth-child(3){transform:translateY(-6px) rotate(-45deg)}

.scroll-progress{position:fixed;top:0;left:0;height:3px;width:0;z-index:300;background:linear-gradient(90deg,var(--cyan),var(--amber))}

/* ---------- footer ---------- */
.site-footer{
  margin-top:clamp(48px,7vw,96px);
  border-top:3px solid var(--amber);
  background:linear-gradient(180deg,var(--ink-2),#08141F);
  color:var(--bone);
}
.footer-grid{
  display:grid;grid-template-columns:minmax(0,1.7fr) minmax(0,1fr) minmax(0,1fr);
  gap:clamp(24px,4vw,56px);
  padding-block:clamp(36px,5vw,64px) clamp(24px,3vw,36px);
  border-bottom:1px solid var(--line);
}
.footer-brand__mark{
  font-family:var(--font-title);font-weight:900;font-size:clamp(22px,2.6vw,30px);
  letter-spacing:.14em;line-height:1.1;
}
.footer-brand__mark span{color:var(--amber)}
.footer-brand__line{
  margin-top:14px;max-width:30em;
  font-size:14px;line-height:1.9;color:rgba(241,235,221,.72);
}
.footer-brand__cta{margin-top:20px}
.footer-col__title{
  font-family:var(--font-mono);font-size:11px;letter-spacing:.24em;
  color:var(--stone);margin-bottom:14px;
  padding-bottom:8px;border-bottom:1px solid var(--line);
}
.footer-col__list{display:grid;gap:10px}
.footer-col__list a{
  font-size:14px;text-decoration:none;color:rgba(241,235,221,.82);
  transition:color .16s var(--ease),padding-left .16s var(--ease);
}
.footer-col__list a:hover{color:var(--cyan);padding-left:4px}
.footer-meta{
  display:grid;gap:18px;
  padding-block:clamp(20px,3vw,30px) clamp(28px,4vw,44px);
}
.footer-contact{
  display:flex;flex-wrap:wrap;align-items:center;gap:8px;
  font-size:13px;line-height:1.9;color:rgba(241,235,221,.7);
}
.footer-legal{
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:14px;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.1em;color:var(--stone);
}
.footer-legal__links{display:flex;flex-wrap:wrap;gap:16px}
.footer-legal__links a{text-decoration:none;color:rgba(241,235,221,.66)}
.footer-legal__links a:hover{color:var(--cyan)}

/* ---------- shared components ---------- */
.btn{
  display:inline-flex;align-items:center;gap:10px;
  padding:12px 22px;border:2px solid transparent;
  font-family:var(--font-body);font-size:15px;font-weight:700;
  text-decoration:none;cursor:pointer;
  transition:transform .18s var(--ease),background-color .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease),box-shadow .18s var(--ease);
}
.btn--primary{background:var(--amber);color:var(--ink);border-color:var(--amber);box-shadow:4px 4px 0 rgba(0,0,0,.5)}
.btn--primary:hover{transform:translate(-2px,-2px);box-shadow:6px 6px 0 rgba(0,0,0,.55)}
.btn--ghost{background:transparent;color:var(--bone);border-color:rgba(241,235,221,.35)}
.btn--ghost:hover{border-color:var(--cyan);color:var(--cyan);transform:translateY(-2px)}
.btn--quiet{background:rgba(53,197,192,.12);color:var(--cyan);border-color:transparent}
.btn--quiet:hover{background:rgba(53,197,192,.2);transform:translateY(-2px)}

.tag{
  display:inline-flex;align-items:center;gap:6px;
  padding:3px 9px;border:1px solid;
  font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;
}
.tag--pass{color:var(--green);border-color:rgba(63,175,138,.55);background:rgba(63,175,138,.1)}
.tag--warn{color:var(--orange);border-color:rgba(224,122,63,.55);background:rgba(224,122,63,.1)}
.tag--link{color:var(--cyan);border-color:rgba(53,197,192,.5);background:rgba(53,197,192,.08)}
.tag--mute{color:var(--stone);border-color:rgba(94,106,114,.55);background:rgba(94,106,114,.1)}

.panel{background:var(--ink-2);border:1px solid var(--line);padding:clamp(18px,2.4vw,28px);box-shadow:var(--shadow-soft)}
.panel--hard{border:2px solid var(--bone);box-shadow:var(--shadow-hard)}

.breadcrumb{margin-block:18px 0}
.breadcrumb__list{
  display:flex;flex-wrap:wrap;gap:8px;
  font-family:var(--font-mono);font-size:12px;letter-spacing:.06em;color:var(--stone);
}
.breadcrumb__list li{display:flex;align-items:center;gap:8px}
.breadcrumb__list li+li::before{content:"/";color:rgba(94,106,114,.7)}
.breadcrumb__list a{text-decoration:none;color:rgba(241,235,221,.72)}
.breadcrumb__list a:hover{color:var(--cyan)}

.section{padding-block:clamp(44px,6.5vw,92px)}
.section__head{display:grid;gap:14px;max-width:64ch;margin-bottom:clamp(22px,3.6vw,42px)}
.section__index{font-family:var(--font-mono);font-size:12px;letter-spacing:.2em;color:var(--amber)}
.section__title{font-size:clamp(26px,3.4vw,42px)}
.lead{font-size:clamp(16px,1.5vw,18px);line-height:1.85;max-width:40em;color:rgba(241,235,221,.82)}
.eyebrow{
  display:inline-block;font-family:var(--font-mono);font-size:11px;
  letter-spacing:.2em;color:var(--stone);
}

.grid{display:grid;gap:clamp(16px,2.2vw,28px)}
.grid--2{grid-template-columns:repeat(2,minmax(0,1fr))}
.grid--3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid--split{grid-template-columns:minmax(0,7fr) minmax(0,4fr)}

.prose{max-width:38em;font-size:17px;line-height:1.9;color:rgba(241,235,221,.88)}
.prose p{margin-bottom:1.1em}
.prose h2,.prose h3{margin:1.6em 0 .6em;font-size:clamp(22px,2.4vw,28px)}
.prose a{color:var(--cyan);text-decoration:underline;text-underline-offset:3px}
.prose ul,.prose ol{list-style:none;display:grid;gap:10px;margin-bottom:1.1em}
.prose li{position:relative;padding-left:26px}
.prose li::before{content:"—";position:absolute;left:0;color:var(--amber);font-family:var(--font-mono)}

.toc{position:sticky;top:24px;padding-left:16px;border-left:2px solid rgba(217,154,43,.5)}
.toc__title{font-family:var(--font-mono);font-size:11px;letter-spacing:.22em;color:var(--stone);margin-bottom:12px}
.toc__list{display:grid;gap:2px}
.toc__link{
  display:flex;gap:10px;align-items:baseline;
  padding:7px 0;text-decoration:none;
  font-size:14px;color:rgba(241,235,221,.7);
  border-left:2px solid transparent;margin-left:-18px;padding-left:16px;
  transition:color .16s var(--ease),background-color .16s var(--ease),border-color .16s var(--ease);
}
.toc__link:hover{color:var(--bone);background:rgba(53,197,192,.08);border-left-color:var(--cyan)}
.toc__link[data-current]{color:var(--amber);border-left-color:var(--amber);font-weight:700}
.toc__num{font-family:var(--font-mono);font-size:11px;color:var(--stone)}
.toc__link[data-current] .toc__num{color:var(--amber)}

.copy-btn{
  display:inline-flex;align-items:center;
  padding:3px 9px;background:transparent;
  border:1px solid rgba(53,197,192,.5);color:var(--cyan);
  font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;
  cursor:pointer;
  transition:background-color .16s var(--ease),color .16s var(--ease),border-color .16s var(--ease);
}
.copy-btn:hover{background:rgba(53,197,192,.16)}
.copy-btn[data-copied]{border-color:var(--green);color:var(--green)}

.media-frame{
  position:relative;overflow:hidden;
  border:1px solid var(--line);
  background-color:var(--ink-3);
  background-image:repeating-linear-gradient(135deg,rgba(53,197,192,.07) 0 10px,transparent 10px 20px);
}
.media-frame img,.media-frame svg,.media-frame video{display:block;width:100%;height:100%;object-fit:cover}
.media-frame--ratio-16-9{aspect-ratio:16/9}
.media-frame--ratio-4-3{aspect-ratio:4/3}
.media-frame--ratio-1-1{aspect-ratio:1/1}
.media-frame--band{aspect-ratio:21/6}
.media-frame__label{
  position:absolute;top:0;left:0;z-index:2;
  padding:6px 12px;background:var(--ink-2);color:var(--cyan);
  border-right:1px solid var(--line);border-bottom:1px solid var(--line);
  font-family:var(--font-mono);font-size:11px;letter-spacing:.14em;
}
.media-frame__caption{
  position:absolute;left:0;right:0;bottom:0;z-index:2;
  padding:14px;font-size:12px;line-height:1.7;color:rgba(241,235,221,.85);
  background:linear-gradient(180deg,transparent,rgba(11,27,43,.92));
}

.to-top{
  position:fixed;right:clamp(14px,3vw,28px);bottom:clamp(14px,3vw,28px);z-index:200;
  display:inline-flex;align-items:center;gap:8px;
  padding:10px 16px;cursor:pointer;
  background:var(--ink-2);color:var(--bone);
  border:2px solid var(--amber);
  font-family:var(--font-mono);font-size:12px;letter-spacing:.1em;
  opacity:0;visibility:hidden;transform:translateY(8px);
  transition:opacity .18s var(--ease),transform .18s var(--ease),visibility .18s var(--ease),background-color .18s var(--ease),color .18s var(--ease);
}
.to-top[data-visible]{opacity:1;visibility:visible;transform:none}
.to-top:hover{background:var(--amber);color:var(--ink)}

/* ---------- responsive ---------- */
@media (max-width:1023px){
  .grid--3{grid-template-columns:repeat(2,minmax(0,1fr))}
  .grid--split{grid-template-columns:minmax(0,1fr)}
  .footer-grid{grid-template-columns:minmax(0,1.4fr) minmax(0,1fr) minmax(0,1fr)}
}

@media (max-width:899px){
  .masthead{
    grid-template-columns:minmax(0,1fr);
    justify-items:center;text-align:center;
    gap:16px;padding-block:22px 18px;
  }
  .masthead__meta{justify-self:center;text-align:center}
  .masthead__meta-sub{letter-spacing:.16em}
  .masthead__cta{justify-self:center;width:100%;justify-content:center}

  .nav-bar__inner{justify-content:space-between;min-height:58px}
  .nav-toggle{display:inline-flex}
  .nav-bar__quick{position:static;transform:none}
  .site-nav{
    position:absolute;left:calc(var(--gutter) * -1);right:calc(var(--gutter) * -1);top:100%;
    display:none;z-index:90;
    background:var(--ink-2);
    border-top:1px solid var(--line);
    border-bottom:2px solid var(--amber);
    box-shadow:0 22px 44px rgba(0,0,0,.55);
  }
  .site-nav[data-open]{display:block}
  .site-nav__list{flex-direction:column;align-items:stretch;gap:0;padding:6px 0}
  .site-nav__link{
    display:block;padding:14px calc(var(--gutter) + 6px);
    border-bottom:1px solid var(--line);
    border-left:3px solid transparent;
  }
  .site-nav__link[aria-current="page"]{
    border-bottom-color:var(--line);
    border-left-color:var(--amber);
    background:rgba(217,154,43,.1);
  }
  .toc{position:static;border-left:none;padding-left:0;border-top:1px solid var(--line);padding-top:16px}
  .toc__link{margin-left:0;padding-left:8px}
}

@media (max-width:719px){
  .grid--2,.grid--3{grid-template-columns:minmax(0,1fr)}
  .footer-grid{grid-template-columns:minmax(0,1fr);gap:28px}
  .media-frame--band{aspect-ratio:16/9}
  .footer-legal{flex-direction:column;align-items:flex-start}
  .status-strip__inner{font-size:10px;letter-spacing:.05em}
  .status-strip__meta{display:none}
  .brand__mark{letter-spacing:.1em;padding-left:.1em}
  .brand__sub{letter-spacing:.22em;padding-left:.22em;font-size:10px}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
  .to-top{transition:none}
}