:root{
  --ink-900:#0B0C0E;
  --ink-700:#1B1E23;
  --gray-500:#5C636E;
  --gray-300:#C3C8CF;
  --gray-100:#EEF0F3;
  --paper:#FBFAF7;
  --signal:#FF5A1F;
  --signal-deep:#D8430F;
  --volt:#2D6BFF;
  --legacy:#0F766E;
  --amber:#B4530A;

  --font-display:"Noto Serif SC","Source Han Serif SC","Songti SC",STSong,serif;
  --font-sans:"Noto Sans SC","Source Han Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --font-mono:"JetBrains Mono","SFMono-Regular",Menlo,Consolas,"Courier New",monospace;

  --fs-hero:clamp(2.4rem,6vw,5.5rem);
  --fs-h2:clamp(1.7rem,3.2vw,2.6rem);
  --fs-h3:clamp(1.12rem,1.5vw,1.35rem);
  --fs-body:1.0625rem;
  --fs-small:.875rem;
  --fs-mono:.8125rem;

  --shell:min(1240px,100% - 40px);
  --gutter:20px;
  --radius-s:8px;
  --radius-m:16px;
  --radius-l:24px;
  --radius-pill:999px;

  --ease:cubic-bezier(.2,.7,.3,1);
  --t-fast:180ms;
  --t-mid:240ms;
}

*,
*::before,
*::after{ box-sizing:border-box; }

html{
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
}

body{
  margin:0;
  background:var(--paper);
  color:var(--ink-900);
  font-family:var(--font-sans);
  font-size:var(--fs-body);
  font-weight:400;
  line-height:1.75;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  overflow-x:hidden;
}

h1,h2,h3,h4,h5,h6{ margin:0; }
h1,h2{
  font-family:var(--font-display);
  font-weight:700;
  line-height:1.05;
  letter-spacing:-.01em;
}
h1{ font-size:var(--fs-hero); }
h2{ font-size:var(--fs-h2); }
h3,h4{
  font-family:var(--font-sans);
  font-weight:600;
  font-size:var(--fs-h3);
  line-height:1.35;
  letter-spacing:.005em;
}
p{ margin:0; }
img{ max-width:100%; }
ul,ol{ margin:0; padding:0; }
li{ list-style:none; }
button{ font:inherit; }
a{ color:inherit; }

:focus-visible{
  outline:2px solid var(--signal);
  outline-offset:2px;
  border-radius:4px;
}

.visually-hidden{
  position:absolute !important;
  width:1px;height:1px;
  padding:0;margin:-1px;
  overflow:hidden;
  clip:rect(0 0 0 0);
  clip-path:inset(50%);
  white-space:nowrap;
  border:0;
}

/* ---------- 容器与栅格 ---------- */

.wrap{
  width:var(--shell);
  margin-inline:auto;
}

.grid{
  display:grid;
  gap:var(--gutter);
}
.grid--6{ grid-template-columns:repeat(6,minmax(0,1fr)); }
.grid--3{ grid-template-columns:repeat(3,minmax(0,1fr)); }
.grid--2{ grid-template-columns:repeat(2,minmax(0,1fr)); }

/* ---------- 跳转链接 ---------- */

.skip-link{
  position:fixed;
  top:10px;
  left:10px;
  z-index:200;
  padding:.7em 1.15em;
  border-radius:var(--radius-pill);
  background:var(--ink-900);
  color:var(--paper);
  font-size:var(--fs-small);
  font-weight:600;
  text-decoration:none;
  transform:translateY(-180%);
  transition:transform var(--t-mid) var(--ease);
}
.skip-link:focus{
  transform:translateY(0);
}

/* ---------- 悬浮胶囊导航 ---------- */

.site-header{
  position:fixed;
  top:0;
  left:0;
  right:0;
  z-index:90;
  pointer-events:none;
}

.header-shell{
  width:var(--shell);
  margin-inline:auto;
  padding-top:18px;
  pointer-events:none;
}

.header-pill{
  position:relative;
  display:flex;
  align-items:center;
  gap:18px;
  padding:9px 10px 9px 18px;
  border-radius:var(--radius-pill);
  background:rgba(251,250,247,.74);
  -webkit-backdrop-filter:blur(16px) saturate(1.5);
  backdrop-filter:blur(16px) saturate(1.5);
  border:1px solid rgba(11,12,14,.10);
  box-shadow:0 14px 40px -24px rgba(11,12,14,.55);
  pointer-events:auto;
  transition:padding var(--t-mid) var(--ease),
             background-color var(--t-mid) var(--ease),
             box-shadow var(--t-mid) var(--ease),
             border-radius var(--t-mid) var(--ease);
}

.site-header.is-condensed .header-pill{
  padding:5px 8px 5px 14px;
  background:rgba(251,250,247,.92);
  border-color:rgba(11,12,14,.14);
  box-shadow:0 18px 46px -26px rgba(11,12,14,.6);
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:10px;
  flex:0 0 auto;
  text-decoration:none;
  color:inherit;
}

.brand-glyph{
  display:grid;
  place-items:center;
  width:34px;
  height:34px;
  border-radius:11px;
  background:var(--ink-900);
  color:var(--paper);
  font-family:var(--font-display);
  font-size:1.05rem;
  font-weight:700;
  line-height:1;
  transition:background-color var(--t-fast) var(--ease), transform var(--t-fast) var(--ease);
}
.brand:hover .brand-glyph{
  background:var(--signal);
  transform:translateY(-1px);
}

.brand-words{
  display:flex;
  flex-direction:column;
  line-height:1.15;
}
.brand-name{
  font-family:var(--font-display);
  font-size:1.05rem;
  font-weight:700;
  letter-spacing:.01em;
  color:var(--ink-900);
  white-space:nowrap;
}
.brand-tag{
  display:block;
  max-height:1.4em;
  overflow:hidden;
  font-family:var(--font-mono);
  font-size:.6875rem;
  letter-spacing:.04em;
  color:var(--gray-500);
  white-space:nowrap;
  transition:max-height var(--t-mid) var(--ease), opacity var(--t-fast) var(--ease);
}
.site-header.is-condensed .brand-tag{
  max-height:0;
  opacity:0;
}

.site-nav{
  display:flex;
  align-items:center;
  justify-content:center;
  gap:12px;
  flex:1 1 auto;
  min-width:0;
}

.nav-list{
  display:flex;
  align-items:center;
  gap:2px;
}

.nav-item{ display:block; }

.nav-link{
  display:block;
  padding:.5em .8em;
  border-radius:var(--radius-pill);
  font-size:.9375rem;
  font-weight:500;
  line-height:1.4;
  color:var(--ink-700);
  text-decoration:none;
  white-space:nowrap;
  transition:background-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}
.nav-link:hover{
  background:rgba(11,12,14,.07);
  color:var(--ink-900);
}
.nav-link[aria-current="page"]{
  background:var(--ink-900);
  color:var(--paper);
}

.nav-tail{ display:flex; align-items:center; }

.legacy-chip{
  display:inline-flex;
  align-items:center;
  gap:.45em;
  padding:.42em .85em;
  border-radius:var(--radius-pill);
  border:1px dashed rgba(15,118,110,.55);
  font-family:var(--font-mono);
  font-size:.75rem;
  letter-spacing:.04em;
  color:var(--legacy);
  text-decoration:none;
  white-space:nowrap;
  transition:background-color var(--t-fast) var(--ease),
             color var(--t-fast) var(--ease),
             border-color var(--t-fast) var(--ease);
}
.legacy-chip::before{
  content:"";
  width:6px;
  height:6px;
  border-radius:50%;
  background:var(--legacy);
  transition:background-color var(--t-fast) var(--ease);
}
.legacy-chip:hover{
  background:var(--legacy);
  color:var(--paper);
  border-style:solid;
  border-color:var(--legacy);
}
.legacy-chip:hover::before{ background:var(--paper); }

.header-actions{
  display:flex;
  align-items:center;
  gap:8px;
  flex:0 0 auto;
}

.nav-toggle{
  display:none;
  align-items:center;
  gap:8px;
  margin-left:auto;
  padding:.5em .9em;
  border-radius:var(--radius-pill);
  border:1px solid var(--gray-300);
  background:var(--paper);
  color:var(--ink-900);
  font-size:var(--fs-mono);
  font-weight:600;
  cursor:pointer;
  transition:border-color var(--t-fast) var(--ease), background-color var(--t-fast) var(--ease);
}
.nav-toggle:hover{ border-color:var(--ink-900); }

.nav-toggle-bars{
  display:inline-flex;
  flex-direction:column;
  gap:4px;
  width:16px;
}
.nav-toggle-bars i{
  display:block;
  height:2px;
  border-radius:2px;
  background:var(--ink-900);
  transition:transform var(--t-fast) var(--ease);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars i:first-child{
  transform:translateY(3px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle-bars i:last-child{
  transform:translateY(-3px) rotate(-45deg);
}

.nav-toggle-text{ display:inline-block; }

/* ---------- 按钮 ---------- */

.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  gap:.45em;
  padding:.62em 1.1em;
  border-radius:var(--radius-pill);
  border:1px solid transparent;
  font-family:var(--font-sans);
  font-size:.9375rem;
  font-weight:600;
  line-height:1.4;
  text-decoration:none;
  white-space:nowrap;
  cursor:pointer;
  transition:background-color var(--t-fast) var(--ease),
             color var(--t-fast) var(--ease),
             border-color var(--t-fast) var(--ease),
             transform var(--t-fast) var(--ease);
}
.btn:active{ transform:translateY(1px); }

.btn-outline{
  background:var(--paper);
  color:var(--ink-900);
  border-color:var(--gray-300);
}
.btn-outline:hover{
  border-color:var(--ink-900);
  background:var(--ink-900);
  color:var(--paper);
}

.btn-signal{
  background:var(--signal);
  color:var(--paper);
  border-color:var(--signal);
}
.btn-signal:hover{
  background:var(--signal-deep);
  border-color:var(--signal-deep);
}

/* ---------- 内容块 ---------- */

.panel{
  padding:22px;
  border-radius:var(--radius-m);
  border:1px solid var(--gray-300);
  background:var(--paper);
}
.panel--muted{ background:var(--gray-100); }
.panel--ink{
  background:var(--ink-900);
  color:var(--paper);
  border-color:var(--ink-900);
}
.panel--glass{
  background:rgba(251,250,247,.66);
  -webkit-backdrop-filter:blur(12px) saturate(1.3);
  backdrop-filter:blur(12px) saturate(1.3);
  border-color:rgba(11,12,14,.10);
}

.tag{
  display:inline-flex;
  align-items:center;
  gap:.4em;
  padding:.28em .7em;
  border-radius:var(--radius-pill);
  border:1px solid var(--gray-300);
  background:var(--paper);
  font-family:var(--font-mono);
  font-size:var(--fs-mono);
  letter-spacing:.04em;
  color:var(--gray-500);
}
.tag--signal{ color:var(--signal); border-color:rgba(255,90,31,.45); background:rgba(255,90,31,.08); }
.tag--volt{ color:var(--volt); border-color:rgba(45,107,255,.38); background:rgba(45,107,255,.08); }
.tag--legacy{ color:var(--legacy); border-color:rgba(15,118,110,.38); background:rgba(15,118,110,.08); }
.tag--ink{ color:var(--paper); background:var(--ink-900); border-color:var(--ink-900); }

/* ---------- 章节刻度带 ---------- */

.section-scale{
  display:flex;
  flex-wrap:wrap;
  border-top:1px solid var(--gray-300);
  border-bottom:1px solid var(--gray-300);
}
.section-scale__item{
  flex:1 1 auto;
  min-width:132px;
  padding:12px 14px 12px 0;
  font-family:var(--font-mono);
  font-size:var(--fs-mono);
  letter-spacing:.04em;
  color:var(--gray-500);
}
.section-scale__item + .section-scale__item{
  padding-left:14px;
  border-left:1px solid var(--gray-300);
}
.section-scale__num{
  display:inline-block;
  margin-right:.55em;
  color:var(--signal);
  font-weight:600;
}

/* ---------- 路径条 ---------- */

.breadcrumb{
  font-family:var(--font-mono);
  font-size:var(--fs-mono);
  letter-spacing:.04em;
  color:var(--gray-500);
}
.breadcrumb__list{
  display:flex;
  flex-wrap:wrap;
  gap:.5em;
}
.breadcrumb__list li + li::before{
  content:"/";
  margin-right:.5em;
  color:var(--gray-300);
}
.breadcrumb a{
  color:var(--gray-500);
  text-decoration:none;
  transition:color var(--t-fast) var(--ease);
}
.breadcrumb a:hover{ color:var(--signal); }

/* ---------- 图片容器 ---------- */

.media-frame{
  position:relative;
  overflow:hidden;
  isolation:isolate;
  border-radius:var(--radius-m);
  border:1px solid var(--gray-300);
  background:var(--gray-100);
  aspect-ratio:16 / 10;
}
.media-frame > img,
.media-frame > picture > img,
.media-frame > svg{
  display:block;
  width:100%;
  height:100%;
  object-fit:cover;
}
.media-frame--3x2{ aspect-ratio:3 / 2; }
.media-frame--1x1{ aspect-ratio:1 / 1; }
.media-frame--4x5{ aspect-ratio:4 / 5; }

.media-frame--cut{
  border-radius:var(--radius-m) var(--radius-m) 0 var(--radius-m);
  clip-path:polygon(0 0,100% 0,100% 82%,86% 100%,0 100%);
}

.media-frame--grid::after{
  content:"";
  position:absolute;
  inset:0;
  pointer-events:none;
  background-image:
    linear-gradient(to right,rgba(11,12,14,.10) 1px,transparent 1px),
    linear-gradient(to bottom,rgba(11,12,14,.10) 1px,transparent 1px);
  background-size:40px 40px;
  mix-blend-mode:multiply;
}

.media-frame--placeholder{
  display:flex;
  align-items:center;
  justify-content:center;
  font-family:var(--font-mono);
  font-size:var(--fs-mono);
  letter-spacing:.06em;
  color:var(--gray-500);
  background-image:
    linear-gradient(to right,rgba(11,12,14,.06) 1px,transparent 1px),
    linear-gradient(to bottom,rgba(11,12,14,.06) 1px,transparent 1px);
  background-size:24px 24px;
}

/* ---------- 正文排版 ---------- */

.prose{ max-width:68ch; }
.prose > p{ margin:0 0 1.15em; }
.prose > p:last-child{ margin-bottom:0; }
.prose h2{ margin:2.2em 0 .7em; font-size:var(--fs-h2); }
.prose h3{
  margin:1.8em 0 .6em;
  font-family:var(--font-sans);
  font-weight:600;
  font-size:var(--fs-h3);
}
.prose ul,.prose ol{ margin:0 0 1.15em; padding-left:1.25em; }
.prose ul li{ list-style:disc; }
.prose ol li{ list-style:decimal; }
.prose li + li{ margin-top:.4em; }
.prose a{
  color:var(--volt);
  text-decoration:underline;
  text-underline-offset:3px;
  text-decoration-thickness:1px;
  transition:color var(--t-fast) var(--ease);
}
.prose a:hover{ color:var(--signal); }
.prose strong{ font-weight:600; }
.prose code{
  padding:.15em .4em;
  border-radius:4px;
  background:var(--gray-100);
  font-family:var(--font-mono);
  font-size:.92em;
}
.prose blockquote{
  margin:1.6em 0;
  padding:.2em 0 .2em 1.2em;
  border-left:2px solid var(--signal);
  color:var(--gray-500);
}
.prose hr{
  margin:2.4em 0;
  border:0;
  border-top:1px solid var(--gray-300);
}

/* ---------- 页脚 ---------- */

.site-footer{
  margin-top:88px;
  background:var(--ink-900);
  color:var(--paper);
  border-top:2px solid var(--signal);
}

.footer-inner{
  width:var(--shell);
  margin-inline:auto;
  padding:64px 0 28px;
}

.footer-grid{
  display:grid;
  grid-template-columns:1.7fr 1fr 1fr 1fr;
  gap:40px 32px;
}

.footer-brand{ min-width:0; }

.footer-mark{
  display:inline-flex;
  align-items:center;
  gap:10px;
  text-decoration:none;
  color:var(--paper);
}
.footer-mark__glyph{
  display:grid;
  place-items:center;
  width:34px;
  height:34px;
  border-radius:11px;
  background:var(--signal);
  color:var(--paper);
  font-family:var(--font-display);
  font-size:1.05rem;
  font-weight:700;
  line-height:1;
}
.footer-mark__name{
  font-family:var(--font-display);
  font-size:1.2rem;
  font-weight:700;
  letter-spacing:.01em;
}

.footer-slogan{
  margin-top:14px;
  font-size:.9375rem;
  color:rgba(251,250,247,.7);
}

.footer-contact{
  display:grid;
  gap:8px;
  margin-top:18px;
}
.footer-contact__row{
  display:flex;
  align-items:baseline;
  gap:12px;
  font-size:.875rem;
}
.footer-contact__key{
  flex:0 0 auto;
  width:2.8em;
  font-family:var(--font-mono);
  font-size:var(--fs-mono);
  letter-spacing:.04em;
  color:rgba(251,250,247,.45);
}
.footer-contact__val{
  color:var(--paper);
  word-break:break-word;
}

.footer-note{
  margin-top:16px;
  font-size:.8125rem;
  line-height:1.7;
  color:rgba(251,250,247,.5);
}

.footer-col__title{
  display:flex;
  align-items:center;
  gap:8px;
  margin-bottom:16px;
  font-family:var(--font-mono);
  font-size:var(--fs-mono);
  font-weight:500;
  letter-spacing:.08em;
  color:var(--paper);
}
.footer-col__title::before{
  content:"";
  width:14px;
  height:1px;
  background:var(--signal);
}

.footer-links{
  display:grid;
  gap:10px;
}
.footer-links a{
  display:inline-block;
  font-size:.9375rem;
  color:rgba(251,250,247,.72);
  text-decoration:none;
  transition:color var(--t-fast) var(--ease), padding-left var(--t-fast) var(--ease);
}
.footer-links a:hover{
  color:var(--paper);
  padding-left:6px;
}

.footer-base{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:10px 24px;
  margin-top:56px;
  padding-top:22px;
  border-top:1px solid rgba(251,250,247,.14);
  font-size:.8125rem;
  color:rgba(251,250,247,.55);
}
.footer-copy{ color:rgba(251,250,247,.75); }
.footer-legacy a{
  font-family:var(--font-mono);
  font-size:var(--fs-mono);
  letter-spacing:.04em;
  color:var(--legacy);
  text-decoration:none;
  border-bottom:1px dashed rgba(15,118,110,.8);
  transition:color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}
.footer-legacy a:hover{
  color:var(--paper);
  border-bottom-color:var(--paper);
}
.footer-icp{
  margin-left:auto;
  font-family:var(--font-mono);
  font-size:var(--fs-mono);
  letter-spacing:.04em;
}

/* ---------- 阅读进度条 ---------- */

.scroll-progress{
  position:fixed;
  top:0;
  left:0;
  right:0;
  height:3px;
  z-index:120;
  background:transparent;
  pointer-events:none;
}
.scroll-progress__fill{
  display:block;
  width:100%;
  height:100%;
  transform:scaleX(0);
  transform-origin:0 50%;
  background:var(--signal);
  transition:transform 120ms linear;
}

/* ---------- 入场显现 ---------- */

.has-js [data-reveal]{
  opacity:0;
  transform:translateY(24px);
  transition:opacity 480ms var(--ease), transform 480ms var(--ease);
}
.has-js [data-reveal].is-visible{
  opacity:1;
  transform:none;
}

/* ---------- 响应式 ---------- */

@media (max-width:1024px){
  .site-header{
    top:auto;
    bottom:0;
  }
  .header-shell{
    width:100%;
    padding:0 12px 12px;
  }
  .header-pill{
    gap:10px;
    padding:8px 10px 8px 14px;
    border-radius:22px;
    background:rgba(251,250,247,.95);
  }
  .site-header.is-condensed .header-pill{
    padding:8px 10px 8px 14px;
    border-radius:22px;
  }
  .brand-tag{ display:none; }

  .site-nav{
    position:absolute;
    left:0;
    right:0;
    bottom:calc(100% + 10px);
    display:block;
    flex:none;
    padding:10px;
    border-radius:20px;
    background:rgba(251,250,247,.97);
    -webkit-backdrop-filter:blur(18px);
    backdrop-filter:blur(18px);
    border:1px solid rgba(11,12,14,.10);
    box-shadow:0 -18px 48px -28px rgba(11,12,14,.6);
    opacity:0;
    visibility:hidden;
    transform:translateY(10px);
    pointer-events:none;
    transition:opacity var(--t-mid) var(--ease),
               transform var(--t-mid) var(--ease),
               visibility var(--t-mid) linear;
  }
  .site-nav[data-open]{
    opacity:1;
    visibility:visible;
    transform:translateY(0);
    pointer-events:auto;
  }

  .nav-list{
    flex-direction:column;
    align-items:stretch;
    gap:2px;
  }
  .nav-link{
    padding:.72em .9em;
    border-radius:12px;
    font-size:1rem;
  }
  .nav-tail{
    margin-top:10px;
    padding-top:10px;
    border-top:1px solid var(--gray-300);
  }
  .legacy-chip{
    width:100%;
    justify-content:center;
  }

  .nav-toggle{ display:inline-flex; }
  .header-actions .btn-outline{ display:none; }

  body{ padding-bottom:86px; }

  .footer-grid{
    grid-template-columns:repeat(3,minmax(0,1fr));
    gap:32px 20px;
  }
  .footer-brand{ grid-column:1 / -1; }
  .grid--6{ grid-template-columns:repeat(3,minmax(0,1fr)); }
}

@media (max-width:720px){
  .grid--3,
  .grid--2{ grid-template-columns:repeat(2,minmax(0,1fr)); }

  .footer-grid{ grid-template-columns:repeat(2,minmax(0,1fr)); }
  .footer-inner{ padding:48px 0 24px; }
  .footer-icp{ margin-left:0; }
  .footer-base{ margin-top:40px; }
}

@media (max-width:640px){
  :root{ --shell:min(1240px,100% - 28px); }
  .grid--6,
  .grid--3,
  .grid--2{ grid-template-columns:1fr; }
  .section-scale__item{
    flex:1 1 100%;
    border-left:0 !important;
    padding-left:0 !important;
    padding-right:0;
  }
  .section-scale__item + .section-scale__item{
    border-top:1px solid var(--gray-300);
  }
}

@media (max-width:520px){
  .header-actions .btn-signal{
    padding:.5em .8em;
    font-size:var(--fs-mono);
  }
  .brand-name{ font-size:1rem; }
  .footer-grid{ grid-template-columns:1fr; }
}

@media (max-width:400px){
  .header-actions{ display:none; }
}

/* ---------- 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;
  }
  .has-js [data-reveal]{
    opacity:1;
    transform:none;
  }
  .scroll-progress__fill{ transition:none; }
  .skip-link{ transition:none; }
}