:root{
  --ink:#000;
  --paper:#fff;
  --mono:"JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --sans:"IBM Plex Sans",system-ui,-apple-system,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  --gut:clamp(14px,4vw,44px);
  --max:1240px;
}

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

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

body{
  margin:0;
  background:var(--paper);
  color:var(--ink);
  font-family:var(--sans);
  font-size:17px;
  line-height:1.65;
  font-weight:400;
  overflow-wrap:break-word;
}

img{max-width:100%;height:auto}
a{color:var(--ink);text-decoration-thickness:1px;text-underline-offset:3px}
:focus-visible{outline:3px solid var(--ink);outline-offset:3px}

/* ---------- 顶部导航：品牌居中、两组有序菜单分列 ---------- */
.site-nav{
  position:sticky;
  top:0;
  z-index:30;
  display:grid;
  grid-template-columns:1fr auto 1fr;
  align-items:center;
  gap:clamp(8px,2vw,26px);
  min-height:66px;
  padding:0 var(--gut);
  background:var(--paper);
  border-bottom:2px solid var(--ink);
}

.nav-group{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  gap:clamp(6px,1.4vw,18px);
  margin:0;
  padding:0;
  list-style:none;
  font-family:var(--mono);
  font-size:13px;
  letter-spacing:.02em;
}

.nav-group--a{justify-content:flex-end}
.nav-group--b{justify-content:flex-start}

.nav-group a{
  display:inline-flex;
  align-items:center;
  min-height:44px;
  padding:0 2px;
  color:var(--ink);
  text-decoration:none;
  border-bottom:2px solid transparent;
  white-space:nowrap;
}
.nav-group a:hover,
.nav-group a:focus-visible{border-bottom-color:var(--ink)}

.brand{
  font-family:var(--mono);
  font-weight:700;
  font-size:clamp(15px,1.7vw,19px);
  letter-spacing:.05em;
  text-decoration:none;
  white-space:nowrap;
  padding:10px 4px;
}

.nav-toggle{
  display:none;
  align-items:center;
  justify-content:center;
  min-height:44px;
  padding:0 12px;
  border:2px solid var(--ink);
  border-radius:0;
  background:var(--paper);
  color:var(--ink);
  font-family:var(--mono);
  font-size:13px;
  letter-spacing:.08em;
  cursor:pointer;
}

/* ---------- 版心：左栏索引 + 右栏正文 ---------- */
main{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:0;
  max-width:var(--max);
  margin:0 auto;
  padding:0 var(--gut) 40px;
}

.story{grid-row:2;grid-column:1;min-width:0}

.rail{
  grid-row:1;
  grid-column:1;
  margin-bottom:26px;
  padding:14px 0 16px;
  border-top:2px solid var(--ink);
  border-bottom:2px solid var(--ink);
}

.rail small{
  display:block;
  font-family:var(--mono);
  font-size:11px;
  letter-spacing:.24em;
  color:var(--ink);
}

.rail-title{
  margin:4px 0 10px;
  font-family:var(--mono);
  font-size:20px;
  line-height:1.2;
  letter-spacing:-.01em;
}

.rail-list{
  margin:0;
  padding:0;
  list-style:none;
  display:flex;
  flex-wrap:wrap;
  gap:0 18px;
}

.rail-list a{
  display:inline-flex;
  align-items:center;
  min-height:38px;
  font-family:var(--mono);
  font-size:12.5px;
  letter-spacing:.01em;
  text-decoration:none;
  color:var(--ink);
  border-bottom:1px solid transparent;
}
.rail-list a:hover,
.rail-list a:focus-visible{border-bottom-color:var(--ink)}

.rail-list li{position:relative;padding-left:0}

/* ---------- 头条 ---------- */
.hero{
  position:relative;
  display:grid;
  justify-items:center;
  align-content:center;
  min-height:45vh;
  padding:34px 0 30px;
  overflow:hidden;
  border-bottom:2px solid var(--ink);
  text-align:center;
}

.hero-num{
  position:absolute;
  top:-.1em;
  left:50%;
  transform:translateX(-50%);
  z-index:0;
  font-family:var(--mono);
  font-weight:700;
  font-size:clamp(96px,26vw,210px);
  line-height:1;
  letter-spacing:-.06em;
  color:var(--ink);
  opacity:.09;
  pointer-events:none;
  user-select:none;
}

.hero-media{
  position:relative;
  z-index:1;
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:10px;
  width:min(460px,100%);
  margin:0 auto 20px;
}

.hero-shot{
  margin:0;
  aspect-ratio:16/9;
  border:2px solid var(--ink);
  background:var(--ink);
  overflow:hidden;
}
.hero-shot--a{transform:translate(-5px,-9px)}
.hero-shot--b{transform:translate(7px,8px)}
.hero-shot .hero-img{width:100%;height:100%;object-fit:cover;display:block}

.hero-copy{position:relative;z-index:1;max-width:26ch;margin:0 auto}

.hero h1{
  margin:0 0 12px;
  font-family:var(--mono);
  font-weight:700;
  font-size:clamp(25px,4.8vw,42px);
  line-height:1.16;
  letter-spacing:-.02em;
}

.hero-lead{
  margin:0 auto;
  max-width:44ch;
  font-size:16px;
  line-height:1.6;
  opacity:.82;
}

/* ---------- 正文 ---------- */
.story{counter-reset:sec}

.story > section{
  counter-increment:sec;
  margin-top:46px;
  padding-top:26px;
  border-top:2px solid var(--ink);
  scroll-margin-top:88px;
}

.story > section::before{
  content:counter(sec,decimal-leading-zero);
  display:block;
  margin-bottom:8px;
  font-family:var(--mono);
  font-size:11px;
  font-weight:600;
  letter-spacing:.28em;
}

.story small{
  display:block;
  margin-bottom:6px;
  font-family:var(--mono);
  font-size:11.5px;
  letter-spacing:.2em;
  opacity:.75;
}

.story h2{
  margin:0 0 18px;
  font-family:var(--mono);
  font-weight:700;
  font-size:clamp(21px,2.7vw,31px);
  line-height:1.24;
  letter-spacing:-.015em;
}

.story h3{
  margin:32px 0 12px;
  font-family:var(--mono);
  font-weight:600;
  font-size:clamp(18px,2vw,21px);
  line-height:1.35;
}

.story p{margin:0 0 18px}
.story ul,.story ol{margin:0 0 20px;padding-left:1.3em}
.story li{margin:0 0 8px}
.story li::marker{font-family:var(--mono);font-size:.85em}

.story > section > p:first-of-type::first-letter{
  float:left;
  padding:.06em .1em 0 0;
  font-family:var(--mono);
  font-size:3.1em;
  font-weight:700;
  line-height:.86;
}

.story blockquote{
  margin:28px 0;
  padding:4px 0 4px 18px;
  border-left:5px solid var(--ink);
  font-family:var(--mono);
  font-size:clamp(16px,1.7vw,19px);
  line-height:1.55;
  letter-spacing:-.01em;
}
.story blockquote p:last-child{margin-bottom:0}
.story blockquote::first-letter{font-size:1em;float:none}

.story figure{margin:26px 0}
.story figcaption{
  margin-top:8px;
  font-family:var(--mono);
  font-size:12px;
  letter-spacing:.05em;
  opacity:.72;
}

.story table{
  width:100%;
  margin:24px 0;
  border-collapse:collapse;
  font-size:16px;
}
.story th,.story td{
  padding:9px 12px;
  border:1px solid var(--ink);
  text-align:left;
  vertical-align:top;
}
.story th{
  font-family:var(--mono);
  font-size:13px;
  letter-spacing:.08em;
}

.story code{
  font-family:var(--mono);
  font-size:.92em;
  padding:1px 4px;
  border:1px solid var(--ink);
}
.story pre{
  margin:22px 0;
  padding:14px;
  border:2px solid var(--ink);
  overflow-x:auto;
  font-family:var(--mono);
  font-size:14px;
  line-height:1.5;
}
.story pre code{border:0;padding:0}

.story hr{
  height:0;
  margin:30px 0;
  border:0;
  border-top:1px dashed var(--ink);
}

.story a{border-bottom:1px solid var(--ink);text-decoration:none}
.story a:hover{background:var(--ink);color:var(--paper)}

/* ---------- 页脚 ---------- */
footer{
  margin-top:56px;
  border-top:3px solid var(--ink);
  padding:0 var(--gut);
}

.f-cta{
  display:flex;
  flex-wrap:wrap;
  align-items:flex-end;
  justify-content:space-between;
  gap:16px;
  padding:36px 0 22px;
  border-bottom:1px solid var(--ink);
}

.f-cta strong{
  font-family:var(--mono);
  font-weight:700;
  font-size:clamp(27px,7vw,62px);
  line-height:.95;
  letter-spacing:-.03em;
  word-break:break-word;
}

.f-top{
  display:inline-flex;
  align-items:center;
  min-height:44px;
  padding:0 16px;
  border:2px solid var(--ink);
  font-family:var(--mono);
  font-size:13px;
  letter-spacing:.08em;
  text-decoration:none;
  white-space:nowrap;
}
.f-top:hover{background:var(--ink);color:var(--paper)}

.f-cols{
  display:grid;
  grid-template-columns:1fr;
  gap:22px;
  padding:26px 0;
  border-bottom:1px solid var(--ink);
}

.f-desc{
  margin:0;
  max-width:34ch;
  font-size:16px;
  line-height:1.6;
  opacity:.85;
}

.f-list{
  margin:0;
  padding:0;
  list-style:none;
}
.f-list a{
  display:inline-flex;
  align-items:center;
  min-height:42px;
  font-family:var(--mono);
  font-size:13px;
  text-decoration:none;
  border-bottom:1px solid transparent;
}
.f-list a:hover,
.f-list a:focus-visible{border-bottom-color:var(--ink)}

.f-base{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:10px 18px;
  padding:14px 0 34px;
}

.f-copy{
  font-family:var(--mono);
  font-size:12px;
  letter-spacing:.06em;
  opacity:.8;
}

.f-list--row{display:flex;flex-wrap:wrap;gap:0 18px}

/* ---------- 动效 ---------- */
.reveal{
  opacity:0;
  transform:translateY(16px);
  transition:opacity .55s ease,transform .55s ease;
}
.reveal.is-in{opacity:1;transform:none}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal{opacity:1;transform:none;transition:none}
}

/* ---------- 中屏 ---------- */
@media (min-width:720px){
  .f-cols{grid-template-columns:1.5fr 1fr 1fr;gap:30px}
}

/* ---------- 宽屏：索引固定左侧 ---------- */
@media (min-width:900px){
  main{
    grid-template-columns:196px minmax(0,1fr);
    column-gap:clamp(26px,3.4vw,60px);
    padding-top:10px;
  }
  .story{grid-column:2;grid-row:1}
  .rail{
    grid-column:1;
    grid-row:1;
    position:sticky;
    top:86px;
    align-self:start;
    margin-bottom:0;
    border-top:0;
    border-bottom:0;
    padding:18px 0 0;
  }
  .rail-list{flex-direction:column;gap:0}
  .rail-list a{min-height:34px}
  .hero{justify-items:start;text-align:left}
  .hero-num{left:auto;right:0;transform:none}
  .hero-copy{margin:0}
  .hero-lead{margin:0}
}

/* ---------- 小屏导航 ---------- */
@media (max-width:820px){
  .site-nav{
    grid-template-columns:1fr auto;
    gap:6px;
    padding:8px var(--gut);
  }
  .nav-toggle{display:inline-flex}
  .brand{
    grid-column:1;
    grid-row:1;
    justify-self:center;
    text-align:center;
  }
  .nav-toggle{grid-column:2;grid-row:1}
  .nav-group{
    display:none;
    grid-column:1 / -1;
    justify-content:flex-start;
    padding-top:6px;
    border-top:1px solid var(--ink);
  }
  .site-nav.is-open .nav-group{display:flex}
  .nav-group--a{grid-row:2}
  .nav-group--b{grid-row:3}
  .nav-group a{min-height:44px;padding:0 4px}
  .rail-list{gap:0 16px}
}
</style>

button[aria-expanded]{min-width:44px;min-height:44px}