/* ===================================================================
   pp王电子 · /assets/site.css
   共享外壳：reset / 变量 / 中文排版 / 头部 / 页脚 / 通用组件
   =================================================================== */

:root{
  --rock-deep:#0B0E13;
  --slate-panel:#141922;
  --slate-deep:#10151D;
  --rock-line:#2A3140;
  --blue:#0A5CFF;
  --violet:#7B2CFF;
  --cyan:#00E5D0;
  --amber:#FF9F1C;
  --moss:#5FA57A;
  --clay:#C96F4A;
  --bone:#F4F1EA;
  --mist:#9AA4B2;

  --rail-w:108px;
  --topbar-h:60px;
  --radius:2px;
  --ease:cubic-bezier(.22,.61,.36,1);

  --font-sans:"Helvetica Neue",Helvetica,Arial,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
  --font-display:"Helvetica Neue",Helvetica,Arial,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono","Courier New",monospace;
}

/* ---------- reset ---------- */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body,h1,h2,h3,h4,h5,h6,p,ul,ol,li,dl,dt,dd,figure,blockquote,fieldset{margin:0;padding:0}
ul,ol{list-style:none}
img,svg,video,canvas{display:block;max-width:100%}
img{height:auto}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0;cursor:pointer}
a{color:inherit}
table{border-collapse:collapse;width:100%}
abbr[title]{text-decoration:none}

/* ---------- base ---------- */
html{background-color:var(--rock-deep)}
body{
  min-height:100vh;
  background-color:var(--rock-deep);
  background-image:
    radial-gradient(920px 540px at 10% -8%, rgba(10,92,255,.22), transparent 62%),
    radial-gradient(760px 480px at 92% 2%, rgba(123,44,255,.16), transparent 60%);
  background-repeat:no-repeat;
  color:var(--bone);
  font-family:var(--font-sans);
  font-size:1rem;
  font-weight:400;
  line-height:1.6;
  letter-spacing:.005em;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  text-rendering:optimizeLegibility;
  padding-left:0;
}
@media (min-width:1024px){
  body{
    padding-left:var(--rail-w);
    background-image:
      radial-gradient(920px 540px at 10% -8%, rgba(10,92,255,.22), transparent 62%),
      radial-gradient(760px 480px at 92% 2%, rgba(123,44,255,.16), transparent 60%),
      repeating-linear-gradient(90deg, rgba(42,49,64,.42) 0 1px, transparent 1px 96px),
      repeating-linear-gradient(0deg, rgba(42,49,64,.30) 0 1px, transparent 1px 96px);
  }
}

::selection{background:rgba(0,229,208,.28);color:var(--bone)}

:focus-visible{
  outline:2px solid var(--cyan);
  outline-offset:2px;
  border-radius:var(--radius);
}

h1,h2,h3,h4{font-family:var(--font-display);font-weight:700;line-height:1.25;letter-spacing:.01em}
h1{font-size:clamp(1.8rem,3.6vw,2.85rem)}
h2{font-size:clamp(1.35rem,2.4vw,2.05rem)}
h3{font-size:clamp(1.08rem,1.7vw,1.35rem)}
p{max-width:68ch}
strong{font-weight:700;color:var(--bone)}
code,kbd,samp{font-family:var(--font-mono);font-size:.8125rem;letter-spacing:.06em}

.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;
}

/* ---------- 容器 / 排版 ---------- */
.wrap{
  width:100%;
  max-width:1180px;
  margin-inline:auto;
  padding-inline:clamp(1rem,3.4vw,3rem);
}
.wrap--narrow{max-width:880px}

.prose{max-width:68ch}
.prose p{margin-bottom:1em;color:var(--bone)}
.prose p:last-child{margin-bottom:0}
.prose ul,.prose ol{margin:0 0 1em;padding-left:1.15rem}
.prose ul li{position:relative;padding-left:.9rem;margin-bottom:.45em}
.prose ul li::before{
  content:"";position:absolute;left:0;top:.72em;width:6px;height:6px;
  background:var(--cyan);clip-path:polygon(0 0,100% 0,100% 70%,70% 100%,0 100%);
}
.prose ol{list-style:decimal;padding-left:1.4rem}
.prose ol li{margin-bottom:.45em}
.prose ol li::marker{font-family:var(--font-mono);font-size:.8125rem;color:var(--cyan)}
.prose a{color:var(--cyan);text-decoration:underline;text-underline-offset:3px;text-decoration-thickness:1px}
.prose a:hover{color:var(--bone)}

.lede{font-size:clamp(.98rem,1.4vw,1.1rem);color:var(--mist);max-width:60ch}

.rule{height:1px;border:0;background:var(--rock-line);margin-block:clamp(1.5rem,3vw,2.5rem)}

/* ---------- 跳转链接 ---------- */
.skip-link{
  position:fixed;top:.5rem;left:.5rem;z-index:999;
  padding:.55rem .9rem;
  background:var(--cyan);color:#04121A;
  font-size:.8125rem;font-weight:700;text-decoration:none;
  transform:translateY(-220%);
  transition:transform .18s var(--ease);
}
.skip-link:focus{transform:translateY(0)}

/* ===================================================================
   头部
   =================================================================== */
.site-header{position:relative;z-index:40}

/* ---- 左侧品牌轨道（桌面常驻） ---- */
.brand-rail{
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:1.5rem;
  position:fixed;
  left:0;top:0;bottom:0;
  width:var(--rail-w);
  padding:1.15rem .8rem 1rem;
  background:linear-gradient(180deg,#0D1420 0%,#0B0E13 52%,#090C11 100%);
  border-right:1px solid var(--rock-line);
  z-index:60;
}
.brand-rail::after{
  content:"";position:absolute;top:0;right:-1px;width:1px;height:38%;
  background:linear-gradient(180deg,var(--cyan),rgba(0,229,208,0));
  opacity:.75;pointer-events:none;
}
.brand-rail__mark{
  display:flex;flex-direction:column;align-items:center;gap:.6rem;
  text-decoration:none;color:var(--bone);
}
.brand-rail__glyph{
  display:grid;place-items:center;
  width:46px;height:46px;
  background:linear-gradient(140deg,var(--blue),var(--violet));
  color:#F7FBFF;
  font-family:var(--font-mono);font-size:.8125rem;font-weight:700;letter-spacing:.08em;
  clip-path:polygon(0 0,100% 0,100% 70%,70% 100%,0 100%);
  transition:filter .18s var(--ease);
}
.brand-rail__mark:hover .brand-rail__glyph{filter:brightness(1.18)}
.brand-rail__name{
  writing-mode:vertical-rl;
  font-size:.9375rem;font-weight:700;letter-spacing:.32em;
  color:var(--bone);
}
.brand-rail__status{
  display:flex;flex-direction:column;align-items:center;gap:.4rem;
  padding-top:1rem;width:100%;
  border-top:1px solid var(--rock-line);
}
.brand-rail__meta{
  font-family:var(--font-mono);font-size:.59375rem;letter-spacing:.04em;
  color:var(--mist);text-align:center;line-height:1.5;
}
.brand-rail__icp{
  margin-top:auto;
  font-family:var(--font-mono);font-size:.5625rem;letter-spacing:.02em;
  color:var(--mist);opacity:.72;text-align:center;line-height:1.5;
}

/* ---- 章节索引 ---- */
.rail-index{width:100%;flex:1 1 auto;min-height:0;overflow:visible}
.rail-index__list{display:flex;flex-direction:column;align-items:center;gap:.35rem}
.rail-index__link{
  position:relative;
  display:flex;align-items:center;justify-content:center;
  width:44px;height:32px;
  border:1px solid transparent;
  color:var(--mist);
  font-family:var(--font-mono);font-size:.6875rem;letter-spacing:.08em;
  text-decoration:none;
  transition:color .18s var(--ease),border-color .18s var(--ease),background-color .18s var(--ease);
}
.rail-index__link:hover,
.rail-index__link:focus-visible{
  color:var(--bone);
  border-color:rgba(0,229,208,.45);
  background:rgba(0,229,208,.07);
}
.rail-index__link[aria-current="true"]{
  color:var(--cyan);
  border-color:rgba(0,229,208,.7);
  background:rgba(0,229,208,.12);
}
.rail-index__num{display:block;line-height:1}
.rail-index__tip{
  position:absolute;left:calc(100% + 10px);top:50%;
  transform:translate(-6px,-50%);
  padding:.35rem .55rem;
  background:var(--slate-panel);
  border:1px solid var(--rock-line);
  border-left:2px solid var(--cyan);
  color:var(--bone);
  font-family:var(--font-sans);font-size:.75rem;letter-spacing:.02em;white-space:nowrap;
  opacity:0;pointer-events:none;
  transition:opacity .18s var(--ease),transform .18s var(--ease);
}
.rail-index__link:hover .rail-index__tip,
.rail-index__link:focus-visible .rail-index__tip,
.rail-index__link[aria-current="true"] .rail-index__tip{
  opacity:1;transform:translate(0,-50%);
}
.rail-index__empty{
  display:none;
  font-family:var(--font-mono);font-size:.5625rem;letter-spacing:.06em;
  color:var(--mist);text-align:center;line-height:1.6;
}
.rail-index[data-empty] .rail-index__empty{display:block}
.rail-index[data-empty] .rail-index__list{display:none}

/* ---- 顶栏 ---- */
.topbar{
  position:sticky;top:0;z-index:50;
  background:rgba(11,14,19,.92);
  -webkit-backdrop-filter:blur(10px);
  backdrop-filter:blur(10px);
  border-bottom:1px solid var(--rock-line);
}
.topbar__inner{
  display:flex;align-items:center;gap:1.25rem;
  min-height:var(--topbar-h);
  padding-inline:clamp(1rem,3.4vw,3rem);
}
.topbar__brand{
  display:none;
  font-size:1.0625rem;font-weight:700;letter-spacing:.02em;
  color:var(--bone);text-decoration:none;
}
.topbar__brand:hover{color:var(--cyan)}
.status-strip{
  margin-right:auto;
  max-width:none;
  font-family:var(--font-mono);font-size:.6875rem;letter-spacing:.06em;
  color:var(--mist);
}

/* ---- 导航 ---- */
.site-nav{display:flex;align-items:center;gap:1.25rem}
.site-nav__list{display:flex;align-items:center;gap:.2rem;counter-reset:nav-item}
.site-nav__list a{
  display:inline-block;
  padding:.45rem .62rem;
  border:1px solid transparent;
  color:var(--mist);
  font-size:.8125rem;letter-spacing:.01em;text-decoration:none;
  transition:color .18s var(--ease),border-color .18s var(--ease),background-color .18s var(--ease);
}
.site-nav__list a:hover{
  color:var(--bone);
  border-color:var(--rock-line);
  background:rgba(20,25,34,.9);
}
.site-nav__list a[aria-current="page"]{
  color:var(--cyan);
  border-color:rgba(0,229,208,.45);
  background:rgba(0,229,208,.07);
}
.site-nav__actions{
  display:flex;align-items:center;gap:.5rem;
  padding-left:1.25rem;
  border-left:1px solid var(--rock-line);
}

/* ---- 移动导航按钮 ---- */
.nav-toggle{
  display:none;align-items:center;gap:.5rem;
  padding:.45rem .7rem;
  border:1px solid var(--rock-line);
  color:var(--bone);
  font-size:.8125rem;letter-spacing:.02em;
  transition:border-color .18s var(--ease),color .18s var(--ease),background-color .18s var(--ease);
}
.nav-toggle:hover{border-color:rgba(0,229,208,.5);color:var(--cyan)}
.nav-toggle[aria-expanded="true"]{
  color:var(--cyan);
  border-color:rgba(0,229,208,.6);
  background:rgba(0,229,208,.08);
}
.nav-toggle__bars{display:flex;flex-direction:column;gap:4px;width:16px}
.nav-toggle__bars i{
  display:block;height:2px;width:100%;
  background:currentColor;
  transition:transform .18s var(--ease),opacity .18s var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(1){transform:translateY(6px) rotate(45deg)}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(2){opacity:0}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars i:nth-child(3){transform:translateY(-6px) rotate(-45deg)}
.nav-toggle__text{font-weight:600}

/* ---- 遮罩 ---- */
.nav-scrim{display:none}

/* ---- 滚动进度 ---- */
.scroll-progress{
  position:absolute;left:0;right:0;bottom:-1px;height:2px;
  overflow:hidden;pointer-events:none;
}
.scroll-progress__bar{
  display:block;height:100%;width:0;
  background:linear-gradient(90deg,var(--blue),var(--violet) 58%,var(--cyan));
  transition:width .08s linear;
}

/* ===================================================================
   页脚
   =================================================================== */
.site-footer{
  margin-top:clamp(3rem,7vw,6rem);
  background:linear-gradient(180deg,rgba(11,14,19,.4),#090C11 42%);
  border-top:1px solid var(--rock-line);
}
.site-footer__inner{
  width:100%;max-width:1180px;margin-inline:auto;
  padding:clamp(2.25rem,4.5vw,3.75rem) clamp(1rem,3.4vw,3rem) clamp(1.75rem,3vw,2.5rem);
  display:grid;
  grid-template-columns:1.6fr 1fr 1.15fr 1.35fr 1fr;
  gap:2.5rem 2rem;
}
.footer-brand{max-width:32ch}
.footer-brand__mark{
  display:inline-block;
  padding-bottom:.35rem;
  font-size:1.1875rem;font-weight:700;letter-spacing:.02em;
  color:var(--bone);text-decoration:none;
  border-bottom:2px solid var(--blue);
  transition:color .18s var(--ease),border-color .18s var(--ease);
}
.footer-brand__mark:hover{color:var(--cyan);border-color:var(--cyan)}
.footer-brand__closing{
  margin-top:1rem;
  font-size:.8125rem;line-height:1.7;color:var(--mist);max-width:34ch;
}
.footer-facts{
  display:flex;flex-wrap:wrap;gap:.55rem 1.4rem;
  margin-top:1.25rem;padding-top:1rem;
  border-top:1px solid var(--rock-line);
}
.footer-facts li{display:flex;flex-direction:column;gap:.15rem}
.footer-facts__key{
  font-family:var(--font-mono);font-size:.5625rem;letter-spacing:.16em;
  color:var(--mist);text-transform:uppercase;
}
.footer-facts__val{
  font-family:var(--font-mono);font-size:.75rem;letter-spacing:.06em;color:var(--bone);
}
.footer-col__title{
  font-family:var(--font-mono);font-size:.6875rem;font-weight:500;letter-spacing:.18em;
  color:var(--mist);text-transform:uppercase;
  padding-bottom:.6rem;margin-bottom:.85rem;
  border-bottom:1px solid var(--rock-line);
}
.footer-col__list{display:flex;flex-direction:column;gap:.55rem}
.footer-col__list a{
  font-size:.8125rem;color:var(--bone);text-decoration:none;
  transition:color .18s var(--ease);
}
.footer-col__list a:hover{color:var(--cyan)}
.footer-col__key{
  display:block;
  font-family:var(--font-mono);font-size:.5625rem;letter-spacing:.14em;
  color:var(--mist);margin-bottom:.2rem;
}
.footer-col__note{
  font-size:.75rem;line-height:1.65;color:var(--mist);
  padding-top:.4rem;border-top:1px dashed rgba(42,49,64,.9);
}
.copy-tag{
  display:inline-block;
  padding:.15rem .35rem;
  border:1px solid var(--rock-line);
  background:rgba(20,25,34,.7);
  color:var(--bone);
  font-family:var(--font-mono);font-size:.6875rem;letter-spacing:.06em;
  word-break:break-all;text-align:left;
  transition:color .18s var(--ease),border-color .18s var(--ease),background-color .18s var(--ease);
}
.copy-tag:hover{color:var(--cyan);border-color:rgba(0,229,208,.5);background:rgba(0,229,208,.07)}
.copy-tag.is-copied{color:var(--cyan);border-color:rgba(0,229,208,.75);background:rgba(0,229,208,.12)}
.copy-status{
  min-height:1.1em;margin-top:.5rem;
  font-family:var(--font-mono);font-size:.625rem;letter-spacing:.06em;
  color:var(--cyan);max-width:none;
}
.site-footer__bar{
  width:100%;max-width:1180px;margin-inline:auto;
  padding:1.1rem clamp(1rem,3.4vw,3rem) 1.6rem;
  border-top:1px solid var(--rock-line);
  display:flex;flex-wrap:wrap;align-items:center;gap:.5rem 1.5rem;
  justify-content:space-between;
}
.site-footer__legal,.site-footer__copy{
  font-family:var(--font-mono);font-size:.625rem;letter-spacing:.08em;color:var(--mist);max-width:none;
}

/* ===================================================================
   通用组件
   =================================================================== */

/* ---- 按钮 ---- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.45rem;
  padding:.6rem 1rem;
  border:1px solid transparent;
  border-radius:var(--radius);
  font-size:.8125rem;font-weight:600;letter-spacing:.02em;
  text-decoration:none;white-space:nowrap;
  transition:background-color .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease),transform .18s var(--ease);
}
.btn:active{transform:translateY(1px)}
.btn--primary{
  background:var(--blue);color:#F7FBFF;
  border-color:rgba(10,92,255,.95);
  box-shadow:0 12px 28px -16px rgba(10,92,255,.95),inset 0 1px 0 rgba(244,241,234,.16);
}
.btn--primary:hover{background:#1D6BFF;border-color:var(--cyan)}
.btn--ghost{
  background:rgba(20,25,34,.85);color:var(--bone);
  border-color:var(--rock-line);
}
.btn--ghost:hover{color:var(--cyan);border-color:rgba(0,229,208,.6)}
.btn--quiet{
  background:transparent;color:var(--mist);
  border-color:transparent;
  text-decoration:underline;text-underline-offset:4px;
}
.btn--quiet:hover{color:var(--cyan)}

/* ---- 标签 ---- */
.tag{
  display:inline-flex;align-items:center;gap:.35em;
  padding:.2rem .45rem;
  border:1px solid var(--rock-line);
  background:rgba(20,25,34,.72);
  color:var(--mist);
  font-size:.75rem;letter-spacing:.02em;white-space:nowrap;
}
.tag--mono{font-family:var(--font-mono);font-size:.6875rem;letter-spacing:.06em}
.tag--cyan{color:var(--cyan);border-color:rgba(0,229,208,.42);background:rgba(0,229,208,.08)}
.tag--amber{color:var(--amber);border-color:rgba(255,159,28,.42);background:rgba(255,159,28,.09)}
.tag--moss{color:var(--moss);border-color:rgba(95,165,122,.45);background:rgba(95,165,122,.1)}
.tag--clay{color:#E08D63;border-color:rgba(201,111,74,.5);background:rgba(201,111,74,.12)}
.tag--blue{color:#9DC0FF;border-color:rgba(10,92,255,.55);background:rgba(10,92,255,.14)}

/* ---- 章节 ---- */
.chapter{
  padding-block:clamp(2.75rem,6.5vw,5.5rem);
  border-top:1px solid var(--rock-line);
  scroll-margin-top:calc(var(--topbar-h) + 18px);
}
.chapter:first-of-type{border-top:0}
.chapter__head{
  display:flex;flex-wrap:wrap;align-items:flex-end;
  gap:.85rem 1.5rem;
  padding-bottom:1.15rem;
  margin-bottom:clamp(1.4rem,3vw,2.25rem);
  border-bottom:1px solid var(--rock-line);
}
.chapter__num{
  display:inline-block;
  padding:.06em .2em .1em;
  background:linear-gradient(140deg,rgba(10,92,255,.32),rgba(123,44,255,.18));
  border-left:3px solid var(--blue);
  color:var(--bone);
  font-family:var(--font-display);font-weight:800;
  font-size:clamp(2.1rem,5vw,4.1rem);
  line-height:.95;letter-spacing:.02em;
  clip-path:polygon(0 0,100% 0,100% 74%,86% 100%,0 100%);
}
.chapter__title{flex:1 1 260px;font-size:clamp(1.35rem,2.4vw,2.05rem)}
.chapter__state{margin-left:auto;display:flex;flex-wrap:wrap;gap:.4rem;align-items:center}
.chapter__lede{
  flex-basis:100%;
  font-size:.9375rem;color:var(--mist);max-width:68ch;
}
.chapter__body{max-width:78ch}

[data-js="on"] .chapter .chapter__title,
[data-js="on"] .chapter .chapter__lede{
  opacity:.45;
  transition:opacity .5s var(--ease);
}
[data-js="on"] .chapter.is-visible .chapter__title,
[data-js="on"] .chapter.is-visible .chapter__lede{opacity:1}

/* ---- 卡片 ---- */
.card{
  position:relative;
  padding:clamp(1.05rem,2.2vw,1.6rem);
  background:linear-gradient(180deg,var(--slate-panel),var(--slate-deep));
  box-shadow:inset 0 0 0 1px var(--rock-line);
  clip-path:polygon(0 0,100% 0,100% calc(100% - 20px),calc(100% - 20px) 100%,0 100%);
  transition:box-shadow .18s var(--ease),transform .18s var(--ease);
}
.card::after{
  content:"";position:absolute;right:0;bottom:0;width:20px;height:20px;
  background:linear-gradient(135deg,
    transparent calc(50% - 1.2px),
    var(--rock-line) calc(50% - 1.2px),
    var(--rock-line) calc(50% - .2px),
    transparent calc(50% - .2px));
  pointer-events:none;
}
.card:hover{
  box-shadow:inset 0 0 0 1px rgba(0,229,208,.55);
  transform:translateY(-2px);
}
.card:hover::after{
  background:linear-gradient(135deg,
    transparent calc(50% - 1.2px),
    rgba(0,229,208,.75) calc(50% - 1.2px),
    rgba(0,229,208,.75) calc(50% - .2px),
    transparent calc(50% - .2px));
}
.card__head{
  display:flex;flex-wrap:wrap;align-items:baseline;gap:.5rem .85rem;
  margin-bottom:.7rem;
}
.card__title{font-size:1.0625rem;font-weight:700;line-height:1.35}
.card__meta{
  margin-left:auto;
  font-family:var(--font-mono);font-size:.625rem;letter-spacing:.08em;color:var(--mist);
}
.card__body{font-size:.875rem;color:var(--mist);max-width:60ch}
.card__body a{color:var(--cyan);text-decoration:underline;text-underline-offset:3px}

/* ---- 栅格 ---- */
.grid{display:grid;gap:clamp(1.1rem,2.6vw,2.25rem)}
.grid--7-5{grid-template-columns:7fr 5fr}
.grid--8-4{grid-template-columns:8fr 4fr}
.grid--4{grid-template-columns:repeat(4,minmax(0,1fr))}

/* ---- 面包屑 ---- */
.breadcrumb{
  display:flex;flex-wrap:wrap;align-items:center;gap:.45rem;
  padding-block:1rem;
  font-family:var(--font-mono);font-size:.6875rem;letter-spacing:.08em;color:var(--mist);
}
.breadcrumb li{display:flex;align-items:center;gap:.45rem}
.breadcrumb li + li::before{content:"/";color:var(--rock-line)}
.breadcrumb a{color:var(--mist);text-decoration:none;transition:color .18s var(--ease)}
.breadcrumb a:hover{color:var(--cyan)}
.breadcrumb [aria-current="page"]{color:var(--bone)}

/* ---- 图片容器 ---- */
.media-frame{
  position:relative;display:block;width:100%;
  aspect-ratio:16 / 9;
  overflow:hidden;
  border:1px solid var(--rock-line);
  background:
    linear-gradient(140deg,rgba(10,92,255,.16),rgba(123,44,255,.12) 55%,rgba(0,229,208,.09)),
    var(--slate-panel);
}
.media-frame img,
.media-frame svg,
.media-frame video{
  width:100%;height:100%;object-fit:cover;display:block;
}
.media-frame--wide{aspect-ratio:21 / 9}
.media-frame--tall{aspect-ratio:4 / 5}
.media-frame--square{aspect-ratio:1 / 1}
.media-frame__caption{
  position:absolute;left:0;right:0;bottom:0;
  padding:.55rem .75rem;
  background:linear-gradient(0deg,rgba(11,14,19,.94),rgba(11,14,19,0));
  font-family:var(--font-mono);font-size:.625rem;letter-spacing:.08em;color:var(--bone);
}
.media-frame__placeholder{
  position:absolute;inset:0;
  display:grid;place-items:center;
  padding:1rem;
  background-image:repeating-linear-gradient(135deg,rgba(42,49,64,.5) 0 1px,transparent 1px 12px);
  font-family:var(--font-mono);font-size:.625rem;letter-spacing:.14em;
  color:var(--mist);text-align:center;
}

/* ---- 折叠面板 ---- */
.foldable{
  border:1px solid var(--rock-line);
  background:rgba(20,25,34,.55);
}
.foldable + .foldable{margin-top:-1px}
.foldable__trigger{
  display:flex;align-items:center;gap:1rem;
  padding:.95rem 1.1rem;
  list-style:none;
  color:var(--bone);
  font-size:.9375rem;font-weight:600;line-height:1.45;
  cursor:pointer;
  transition:color .18s var(--ease),background-color .18s var(--ease);
}
.foldable__trigger::-webkit-details-marker{display:none}
.foldable__trigger::after{
  content:"+";margin-left:auto;
  font-family:var(--font-mono);font-size:.9375rem;color:var(--cyan);
}
.foldable[open] .foldable__trigger::after{content:"−"}
.foldable__trigger:hover{color:var(--cyan);background:rgba(0,229,208,.05)}
.foldable__body{
  padding:0 1.1rem 1.1rem;
  border-top:1px solid var(--rock-line);
  padding-top:.9rem;
  font-size:.875rem;color:var(--mist);
}
.foldable__body p{margin-bottom:.8em}
.foldable__body p:last-child{margin-bottom:0}

/* ---- 时间线 ---- */
.timeline{
  position:relative;
  padding-left:1.4rem;
  border-left:1px solid var(--rock-line);
}
.timeline__item{position:relative;padding:0 0 2rem 1rem}
.timeline__item:last-child{padding-bottom:0}
.timeline__item::before{
  content:"";position:absolute;left:-1.44rem;top:.45rem;
  width:9px;height:9px;
  background:var(--rock-deep);
  border:1px solid var(--cyan);
}
.timeline__meta{
  display:block;margin-bottom:.35rem;
  font-family:var(--font-mono);font-size:.625rem;letter-spacing:.1em;color:var(--mist);
}

/* ---- 数据块 ---- */
.stat{display:flex;flex-direction:column;gap:.2rem}
.stat__value{
  font-family:var(--font-display);font-weight:800;letter-spacing:.02em;
  font-size:clamp(1.55rem,3vw,2.35rem);line-height:1.1;color:var(--bone);
}
.stat__key{
  font-family:var(--font-mono);font-size:.625rem;letter-spacing:.16em;
  color:var(--mist);text-transform:uppercase;
}

/* ===================================================================
   响应式
   =================================================================== */
@media (max-width:1140px){
  .site-footer__inner{grid-template-columns:1.5fr 1fr 1fr;gap:2.25rem 1.75rem}
  .footer-brand{grid-column:1 / -1}
}
@media (max-width:1023px){
  :root{--topbar-h:86px}

  .brand-rail{display:none}

  .topbar__inner{
    display:grid;
    grid-template-columns:1fr auto;
    grid-template-areas:
      "brand toggle"
      "status status";
    align-content:center;
    gap:.28rem .75rem;
    min-height:var(--topbar-h);
    padding:.65rem 1rem;
  }
  .topbar__brand{display:inline-flex;grid-area:brand;align-items:center}
  .nav-toggle{display:inline-flex;grid-area:toggle;margin-left:auto}
  .status-strip{
    grid-area:status;margin:0;
    font-size:.59375rem;letter-spacing:.04em;
    white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
  }

  .site-nav{
    position:fixed;
    top:var(--topbar-h);right:0;bottom:0;
    width:min(84vw,336px);
    display:flex;flex-direction:column;align-items:stretch;gap:0;
    padding:1.25rem 1.25rem 2rem;
    overflow-y:auto;
    background:linear-gradient(180deg,#0E131C,#0B0E13);
    border-left:1px solid var(--rock-line);
    transform:translateX(103%);
    transition:transform .22s var(--ease);
    z-index:46;
  }
  .site-nav[data-open]{transform:translateX(0)}

  .site-nav__list{flex-direction:column;align-items:stretch;gap:0}
  .site-nav__list li{counter-increment:nav-item}
  .site-nav__list a{
    display:flex;align-items:center;gap:.75rem;
    padding:.85rem .2rem;
    border:0;border-bottom:1px solid var(--rock-line);
    border-radius:0;
    font-size:.9375rem;color:var(--bone);
  }
  .site-nav__list a::before{
    content:counter(nav-item,decimal-leading-zero);
    font-family:var(--font-mono);font-size:.625rem;letter-spacing:.06em;color:var(--cyan);
  }
  .site-nav__list a:hover{border-color:rgba(0,229,208,.45);background:rgba(0,229,208,.05)}
  .site-nav__list a[aria-current="page"]{
    border-color:rgba(0,229,208,.6);
    background:rgba(0,229,208,.08);
    color:var(--cyan);
  }
  .site-nav__actions{
    flex-direction:column;align-items:stretch;gap:.6rem;
    padding:1.25rem 0 0;
    border-left:0;
  }
  .site-nav__actions .btn{width:100%}

  .nav-scrim{
    display:block;
    position:fixed;inset:var(--topbar-h) 0 0 0;
    background:rgba(6,9,14,.68);
    opacity:0;pointer-events:none;
    transition:opacity .22s var(--ease);
    z-index:44;
  }
  .nav-scrim[data-open]{opacity:1;pointer-events:auto}

  .grid--7-5,.grid--8-4{grid-template-columns:1fr}
  .grid--4{grid-template-columns:repeat(2,minmax(0,1fr))}
}

@media (max-width:767px){
  .site-footer__inner{grid-template-columns:1fr;gap:2rem}
  .footer-brand{grid-column:auto}
  .site-footer__bar{flex-direction:column;align-items:flex-start;gap:.45rem}
  .chapter__state{margin-left:0;flex-basis:100%}
  .grid--4{grid-template-columns:1fr}
  .card:hover{transform:none}
}

/* ===================================================================
   无障碍与动效偏好
   =================================================================== */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{
    animation-duration:.001ms!important;
    animation-iteration-count:1!important;
    transition-duration:.001ms!important;
  }
  .scroll-progress__bar{transition:none}
  .card:hover{transform:none}
  [data-js="on"] .chapter .chapter__title,
  [data-js="on"] .chapter .chapter__lede{opacity:1;transition:none}
}

@media print{
  body{background:#fff;color:#000;padding-left:0}
  .brand-rail,.nav-toggle,.nav-scrim,.scroll-progress,.skip-link{display:none!important}
  .topbar{position:static;background:none;border-color:#999}
}