/* ============================================================
   /assets/site.css — 共享外壳与通用组件
   01 tokens / 02 reset / 03 skip link / 04 header / 05 footer
   06 layout / 07 typography / 08 buttons / 09 blocks
   10 panels / 11 track rail / 12 media / 13 motion / 14 responsive
   ============================================================ */

/* ---------- 01. tokens ---------- */
:root{
  --ink:#0B1B2B;
  --panel:#12283D;
  --track:#1E3A52;
  --teal:#4FE0C8;
  --amber:#E8A94B;
  --paper:#F5F2EB;
  --muted:#A9B6C4;
  --sand:#C7C3BB;
  --alert:#E4674B;
  --mint:#D9F3EC;

  --line:rgba(30,58,82,.9);
  --line-soft:rgba(30,58,82,.55);

  --font-display:"Songti SC","Noto Serif SC","Source Han Serif SC","Times New Roman",Georgia,serif;
  --font-sans:"PingFang SC","Hiragino Sans GB","Source Han Sans SC","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-mono:"JetBrains Mono","SFMono-Regular","DejaVu Sans Mono",Consolas,"Courier New",monospace;

  --radius-lg:24px;
  --radius-md:18px;
  --radius-sm:10px;
  --gutter:24px;
  --measure:1200px;

  --ease:cubic-bezier(.2,.7,.3,1);
  --shadow-soft:0 22px 48px -34px rgba(0,0,0,.95);
}

/* ---------- 02. reset & base ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;text-size-adjust:100%;scroll-behavior:smooth}
body{
  margin:0;
  background:var(--ink);
  color:var(--paper);
  font-family:var(--font-sans);
  font-size:17px;
  line-height:1.85;
  letter-spacing:.01em;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
h1,h2,h3,h4,p,figure,dl,dd{margin:0}
dd{margin-left:0}
ul,ol{margin:0;padding:0;list-style:none}
img,svg{display:block;max-width:100%}
a{color:var(--teal);text-decoration:none}
button{font:inherit;color:inherit;background:none;border:0}
button{cursor:pointer}
::selection{background:rgba(79,224,200,.28);color:var(--paper)}
:focus-visible{outline:2px solid var(--teal);outline-offset:3px;border-radius:4px}

/* ---------- 03. skip link ---------- */
.skip-link{
  position:absolute;
  left:16px;
  top:-72px;
  z-index:200;
  padding:10px 20px;
  background:var(--teal);
  color:#062430;
  font-size:14px;
  font-weight:700;
  letter-spacing:.06em;
  border-radius:0 0 var(--radius-sm) var(--radius-sm);
  transition:top .2s var(--ease);
}
.skip-link:focus{top:0}

/* ---------- 04. header ---------- */
.site-header{
  position:sticky;
  top:0;
  z-index:80;
  background:linear-gradient(180deg,rgba(11,27,43,.99),rgba(11,27,43,.93));
  border-bottom:1px solid var(--line);
  -webkit-backdrop-filter:blur(10px);
  backdrop-filter:blur(10px);
  transition:box-shadow .25s var(--ease);
}
.site-header[data-compact]{box-shadow:0 16px 34px -26px #000}
.scroll-progress{
  position:absolute;
  left:0;right:0;bottom:-1px;
  height:2px;
  background:linear-gradient(90deg,var(--teal),var(--amber));
  transform:scaleX(var(--progress,0));
  transform-origin:left center;
  transition:transform .12s linear;
  pointer-events:none;
}
.masthead{
  max-width:var(--measure);
  margin:0 auto;
  padding:20px var(--gutter) 16px;
  display:grid;
  grid-template-columns:minmax(0,1fr) auto minmax(0,1fr);
  align-items:center;
  gap:18px;
  transition:padding .3s var(--ease);
}
.masthead__meta{
  display:flex;
  flex-direction:column;
  gap:2px;
  font-size:11px;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:var(--muted);
}
.meta-line{display:block;line-height:1.6}
.meta-line--mono{
  font-family:var(--font-mono);
  letter-spacing:.06em;
  color:var(--sand);
  opacity:.7;
  font-variant-numeric:tabular-nums;
}
.masthead__brand{
  display:block;
  text-align:center;
  text-decoration:none;
  font-family:var(--font-display);
  font-size:clamp(26px,3.2vw,40px);
  line-height:1.08;
  letter-spacing:-.02em;
  color:var(--paper);
  transition:color .2s var(--ease),font-size .3s var(--ease);
}
.masthead__brand:hover{color:var(--teal)}
.brand-mark__sub{
  display:block;
  margin-top:7px;
  font-family:var(--font-mono);
  font-size:10px;
  line-height:1;
  letter-spacing:.42em;
  text-transform:uppercase;
  color:var(--teal);
  opacity:.75;
}
.masthead__status{
  display:flex;
  align-items:center;
  justify-content:flex-end;
  flex-wrap:wrap;
  gap:10px;
}
.version-pill{
  display:inline-flex;
  align-items:center;
  padding:6px 13px;
  border-radius:999px;
  background:var(--teal);
  border:1px solid var(--teal);
  color:#062430;
  font-family:var(--font-mono);
  font-size:14px;
  font-weight:700;
  line-height:1.4;
  letter-spacing:.04em;
  font-variant-numeric:tabular-nums;
}
.revision-chip{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:6px 13px;
  border-radius:999px;
  border:1px solid var(--line);
  background:rgba(30,58,82,.45);
  font-size:11px;
  line-height:1.5;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:var(--muted);
}
.revision-chip time{
  font-family:var(--font-mono);
  font-size:12px;
  letter-spacing:.06em;
  text-transform:none;
  color:var(--amber);
  font-variant-numeric:tabular-nums;
}
.nav-toggle{
  display:none;
  align-items:center;
  gap:9px;
  padding:9px 15px;
  border-radius:999px;
  border:1px solid var(--line);
  background:rgba(30,58,82,.55);
  color:var(--paper);
  font-size:13px;
  letter-spacing:.12em;
  transition:color .2s var(--ease),border-color .2s var(--ease),background .2s var(--ease);
}
.nav-toggle:hover{color:var(--teal);border-color:var(--teal)}
.nav-toggle[aria-expanded="true"]{background:rgba(79,224,200,.14);border-color:var(--teal);color:var(--teal)}
.nav-toggle__bars{
  position:relative;
  display:inline-block;
  width:16px;
  height:2px;
  background:currentColor;
  border-radius:2px;
}
.nav-toggle__bars::before,
.nav-toggle__bars::after{
  content:"";
  position:absolute;
  left:0;
  width:16px;
  height:2px;
  background:currentColor;
  border-radius:2px;
  transition:transform .22s var(--ease);
}
.nav-toggle__bars::before{top:-5px}
.nav-toggle__bars::after{top:5px}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before{transform:translateY(5px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after{transform:translateY(-5px) rotate(-45deg)}
.nav-toggle__label{white-space:nowrap}

.nav-rail{
  border-top:1px solid var(--line);
  background:rgba(18,40,61,.5);
}
.nav-rail__list{
  max-width:var(--measure);
  margin:0 auto;
  padding:0 var(--gutter);
  display:flex;
  gap:4px;
  overflow-x:auto;
  -webkit-overflow-scrolling:touch;
}
.nav-rail__link{
  display:block;
  padding:13px 16px;
  font-size:14px;
  line-height:1.5;
  letter-spacing:.06em;
  color:var(--muted);
  white-space:nowrap;
  border-bottom:2px solid transparent;
  transition:color .2s var(--ease),background .2s var(--ease),border-color .2s var(--ease);
}
.nav-rail__link:hover{color:var(--paper);background:rgba(79,224,200,.07)}
.nav-rail__link[aria-current="page"]{
  color:var(--teal);
  border-bottom-color:var(--teal);
  background:rgba(79,224,200,.05);
}
.site-header[data-compact] .masthead{padding:8px var(--gutter)}
.site-header[data-compact] .masthead__brand{font-size:clamp(20px,2vw,24px)}
.site-header[data-compact] .brand-mark__sub{display:none}
.site-header[data-compact] .meta-line--mono{opacity:.45}

/* ---------- 05. footer ---------- */
.site-footer{
  position:relative;
  margin-top:96px;
  background:linear-gradient(180deg,#0B1B2B 0%,#0F2438 55%,#12283D 100%);
  border-top:1px solid var(--line);
  color:var(--muted);
}
.site-footer::before{
  content:"";
  position:absolute;
  top:-1px;left:0;right:0;
  height:2px;
  background:linear-gradient(90deg,var(--teal),rgba(79,224,200,0) 44%,rgba(232,169,75,0) 60%,var(--amber));
}
.footer-grid{
  max-width:var(--measure);
  margin:0 auto;
  padding:56px var(--gutter) 40px;
  display:grid;
  grid-template-columns:1.5fr 1fr 1fr 1.3fr;
  gap:36px;
}
.footer-col{min-width:0}
.footer-brandline{
  font-family:var(--font-display);
  font-size:24px;
  line-height:1.2;
  letter-spacing:-.01em;
  color:var(--paper);
  margin-bottom:12px;
}
.footer-note{
  font-size:14px;
  line-height:1.75;
  color:var(--muted);
  max-width:34ch;
}
.footer-stamp{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  margin-top:16px;
}
.footer-heading{
  font-family:var(--font-mono);
  font-size:11px;
  line-height:1.6;
  letter-spacing:.18em;
  text-transform:uppercase;
  color:var(--teal);
  margin-bottom:14px;
}
.footer-list li + li{margin-top:9px}
.footer-link{
  color:var(--muted);
  font-size:15px;
  line-height:1.5;
  border-bottom:1px solid transparent;
  transition:color .2s var(--ease),border-color .2s var(--ease);
}
.footer-link:hover{color:var(--paper);border-bottom-color:var(--teal)}
.footer-link--sm{font-size:12px;letter-spacing:.06em}
.footer-contact{
  display:grid;
  gap:11px;
  font-size:14px;
}
.footer-contact__row{
  display:grid;
  grid-template-columns:auto minmax(0,1fr);
  gap:12px;
  align-items:baseline;
}
.footer-contact dt{
  font-size:11px;
  line-height:1.8;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:var(--muted);
  white-space:nowrap;
  opacity:.8;
}
.footer-contact dd{
  color:var(--paper);
  font-size:14px;
  line-height:1.65;
  word-break:break-word;
}
.footer-bottom{
  max-width:var(--measure);
  margin:0 auto;
  padding:18px var(--gutter) 30px;
  border-top:1px solid var(--line);
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:12px;
  font-family:var(--font-mono);
  font-size:12px;
  line-height:1.7;
  letter-spacing:.06em;
  color:var(--muted);
}
.footer-bottom__legal{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:10px;
}
.footer-bottom__dot{color:var(--track)}

/* ---------- 06. layout ---------- */
.container{
  width:100%;
  max-width:var(--measure);
  margin:0 auto;
  padding:0 var(--gutter);
}
.container--narrow{max-width:720px}
.section{padding:72px 0}
.section--tint{background:var(--panel)}
.divider-track{
  height:1px;
  border:0;
  margin:0;
  background:linear-gradient(90deg,transparent,var(--track) 12%,var(--track) 88%,transparent);
}
.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))}
.breadcrumb{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  padding:22px 0 4px;
  font-family:var(--font-mono);
  font-size:11px;
  line-height:1.6;
  letter-spacing:.14em;
  text-transform:uppercase;
  color:var(--muted);
}
.breadcrumb a{color:var(--muted);transition:color .2s var(--ease)}
.breadcrumb a:hover{color:var(--teal)}
.breadcrumb__sep{color:var(--track)}
.breadcrumb [aria-current="page"]{color:var(--paper)}

/* ---------- 07. typography ---------- */
h1,.h1{
  font-family:var(--font-display);
  font-size:clamp(34px,5vw,72px);
  line-height:1.06;
  letter-spacing:-.02em;
  color:var(--paper);
  font-weight:400;
}
h2,.h2{
  font-family:var(--font-sans);
  font-size:clamp(25px,3vw,38px);
  line-height:1.22;
  letter-spacing:.005em;
  font-weight:700;
  color:var(--paper);
}
h3,.h3{
  font-family:var(--font-sans);
  font-size:20px;
  line-height:1.45;
  font-weight:700;
  color:var(--paper);
}
p{max-width:42em}
.lede{
  font-size:clamp(17px,1.5vw,20px);
  line-height:1.8;
  color:var(--muted);
  max-width:36em;
}
.eyebrow{
  display:inline-block;
  font-family:var(--font-mono);
  font-size:12px;
  line-height:1.6;
  letter-spacing:.18em;
  text-transform:uppercase;
  color:var(--teal);
}
.section-number{
  display:inline-block;
  font-family:var(--font-mono);
  font-size:14px;
  line-height:1.6;
  letter-spacing:.2em;
  color:var(--amber);
  font-variant-numeric:tabular-nums;
}
.mono{
  font-family:var(--font-mono);
  font-size:.92em;
  letter-spacing:.02em;
  font-variant-numeric:tabular-nums;
}

/* ---------- 08. buttons ---------- */
.btn{
  display:inline-flex;
  align-items:center;
  gap:10px;
  padding:13px 26px;
  border-radius:999px;
  border:1px solid var(--teal);
  background:var(--teal);
  color:#062430;
  font-size:15px;
  font-weight:700;
  line-height:1.5;
  letter-spacing:.04em;
  text-decoration:none;
  transition:background .2s var(--ease),color .2s var(--ease),border-color .2s var(--ease),transform .2s var(--ease);
}
.btn:hover{background:transparent;color:var(--teal);transform:translateY(-1px)}
.btn--ghost{
  background:transparent;
  color:var(--paper);
  border-color:var(--line);
}
.btn--ghost:hover{border-color:var(--teal);color:var(--teal);background:rgba(79,224,200,.07)}
.btn--amber{
  background:var(--amber);
  border-color:var(--amber);
  color:#2B1B05;
}
.btn--amber:hover{background:transparent;color:var(--amber)}

/* ---------- 09. blocks ---------- */
.card{
  position:relative;
  background:var(--panel);
  border:1px solid var(--line);
  border-radius:var(--radius-md);
  padding:24px;
  box-shadow:var(--shadow-soft);
  transition:border-color .24s var(--ease),background .24s var(--ease);
}
.card:hover{border-color:rgba(79,224,200,.4)}
.card--paper{
  background:var(--paper);
  border-color:var(--sand);
  color:var(--ink);
}
.card--paper h3,.card--paper h2{color:var(--ink)}
.card--paper p{color:#33414E}
.card__meta{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:8px;
  margin-bottom:12px;
}
.tag{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:4px 11px;
  border-radius:999px;
  border:1px solid rgba(79,224,200,.4);
  background:rgba(79,224,200,.12);
  color:var(--teal);
  font-size:11px;
  line-height:1.6;
  letter-spacing:.14em;
  text-transform:uppercase;
}
.tag--amber{
  border-color:rgba(232,169,75,.45);
  background:rgba(232,169,75,.13);
  color:var(--amber);
}
.tag--alert{
  border-color:rgba(228,103,75,.5);
  background:rgba(228,103,75,.13);
  color:var(--alert);
}
.card--paper .tag{
  border-color:rgba(11,27,43,.18);
  background:var(--mint);
  color:#0B4C43;
}
.timestamp{
  font-family:var(--font-mono);
  font-size:12px;
  line-height:1.6;
  letter-spacing:.06em;
  color:var(--muted);
  font-variant-numeric:tabular-nums;
}

/* ---------- 10. panels ---------- */
.panel{
  border:1px solid var(--line);
  border-radius:var(--radius-md);
  background:rgba(18,40,61,.6);
  overflow:hidden;
}
.panel + .panel{margin-top:12px}
.panel__summary{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  padding:18px 22px;
  cursor:pointer;
  font-size:16px;
  font-weight:700;
  line-height:1.6;
  color:var(--paper);
  list-style:none;
}
.panel__summary::-webkit-details-marker{display:none}
.panel__summary::after{
  content:"+";
  flex:none;
  font-family:var(--font-mono);
  font-size:18px;
  line-height:1;
  color:var(--teal);
  transition:transform .24s var(--ease);
}
.panel[open] .panel__summary::after{transform:rotate(45deg)}
.panel__body{
  padding:0 22px 22px;
  font-size:16px;
  line-height:1.85;
  color:var(--muted);
  animation:panelFade .16s var(--ease);
}
@keyframes panelFade{from{opacity:0}to{opacity:1}}

/* ---------- 11. track rail ---------- */
.track-rail{
  position:relative;
  padding-left:24px;
}
.track-rail::before{
  content:"";
  position:absolute;
  left:5px;
  top:8px;
  bottom:8px;
  width:1px;
  background:var(--line);
}
.track-item{
  position:relative;
  padding:0 0 22px;
}
.track-item:last-child{padding-bottom:0}
.track-item::before{
  content:"";
  position:absolute;
  left:-23px;
  top:9px;
  width:9px;
  height:9px;
  border-radius:50%;
  background:var(--ink);
  border:1px solid var(--track);
}
.track-item[data-state="current"]::before{
  background:var(--teal);
  border-color:var(--teal);
  box-shadow:0 0 0 4px rgba(79,224,200,.16);
}
.track-item[data-state="revised"]::before{
  background:var(--amber);
  border-color:var(--amber);
}

/* ---------- 12. media ---------- */
.media-frame{
  position:relative;
  display:grid;
  place-items:center;
  min-height:180px;
  border-radius:var(--radius-lg);
  border:1px solid var(--line);
  overflow:hidden;
  background:
    radial-gradient(120% 120% at 12% 8%,rgba(79,224,200,.16),transparent 58%),
    radial-gradient(95% 95% at 88% 92%,rgba(232,169,75,.14),transparent 62%),
    linear-gradient(160deg,#12283D 0%,#0B1B2B 100%);
}
.media-frame::before{
  content:"";
  position:absolute;
  inset:0;
  background-image:
    repeating-linear-gradient(90deg,rgba(199,195,187,.08) 0 1px,transparent 1px 44px),
    repeating-linear-gradient(0deg,rgba(199,195,187,.06) 0 1px,transparent 1px 44px);
  pointer-events:none;
}
.media-frame img{
  position:relative;
  width:100%;
  height:100%;
  object-fit:cover;
}
.media-frame__label{
  position:relative;
  padding:14px 18px;
  font-family:var(--font-mono);
  font-size:11px;
  line-height:1.7;
  letter-spacing:.18em;
  text-transform:uppercase;
  color:var(--muted);
  text-align:center;
}
.media-frame--16x9{aspect-ratio:16/9}
.media-frame--4x3{aspect-ratio:4/3}
.media-frame--1x1{aspect-ratio:1/1}

/* ---------- 13. motion ---------- */
html.has-js [data-reveal]{
  opacity:0;
  transform:translateY(12px);
  transition:opacity .32s var(--ease),transform .32s var(--ease);
  transition-delay:calc(var(--reveal-index,0) * 60ms);
  will-change:opacity,transform;
}
html.has-js [data-reveal].is-visible{
  opacity:1;
  transform:none;
  will-change:auto;
}

/* ---------- 14. responsive ---------- */
@media (max-width:1100px){
  .footer-grid{grid-template-columns:1fr 1fr;gap:32px}
}

@media (max-width:1000px){
  .masthead{
    grid-template-columns:minmax(0,1fr) auto auto;
    gap:10px;
    padding:12px 18px;
  }
  .masthead__meta{display:none}
  .masthead__brand{
    text-align:left;
    justify-self:start;
    font-size:clamp(21px,4vw,27px);
  }
  .brand-mark__sub{display:none}
  .masthead__status{justify-self:end;gap:8px}
  .revision-chip{display:none}
  .nav-toggle{display:inline-flex}
  .site-header[data-compact] .masthead{padding:10px 18px}
  .site-header[data-compact] .masthead__brand{font-size:clamp(19px,3.6vw,23px)}

  .nav-rail{
    max-height:0;
    overflow:hidden;
    border-top:1px solid transparent;
    background:rgba(11,27,43,.98);
    transition:max-height .3s var(--ease),border-color .3s var(--ease);
  }
  .nav-rail[data-open]{
    max-height:70vh;
    overflow-y:auto;
    border-top-color:var(--line);
  }
  .nav-rail__list{
    flex-direction:column;
    gap:0;
    padding:6px 18px 18px;
    overflow:visible;
  }
  .nav-rail__link{
    padding:14px 10px;
    font-size:15px;
    border-bottom:1px solid var(--line-soft);
    border-left:2px solid transparent;
  }
  .site-header[data-compact] .nav-rail__link{padding:13px 10px}
  .nav-rail__link[aria-current="page"]{
    border-bottom-color:var(--line-soft);
    border-left-color:var(--teal);
    background:rgba(79,224,200,.08);
  }
  .nav-rail__link:hover{background:rgba(79,224,200,.06)}
}

@media (max-width:860px){
  body{font-size:16px;line-height:1.75}
  .section{padding:52px 0}
  .grid--2,.grid--3{grid-template-columns:minmax(0,1fr)}
  .site-footer{margin-top:64px}
  .footer-grid{padding:44px var(--gutter) 32px}
}

@media (max-width:620px){
  :root{--gutter:18px}
  h1,.h1{font-size:clamp(30px,8vw,38px);line-height:1.12}
  h2,.h2{font-size:clamp(22px,6vw,28px)}
  .masthead{padding:10px 18px}
  .version-pill{font-size:13px;padding:5px 11px}
  .nav-toggle{padding:8px 13px}
  .footer-grid{grid-template-columns:minmax(0,1fr);gap:28px;padding:36px 18px 26px}
  .footer-bottom{flex-direction:column;align-items:flex-start;padding:16px 18px 26px}
  .footer-contact__row{grid-template-columns:minmax(0,1fr);gap:2px}
  .card{padding:20px}
  .panel__summary{padding:16px 18px;font-size:15px}
  .panel__body{padding:0 18px 18px}
}

@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.has-js [data-reveal]{opacity:1;transform:none;transition:none}
  .scroll-progress{transition:none}
  .btn:hover{transform:none}
}