@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

:root{
  --ink:#000000;
  --paper:#ffffff;
  --hair:#dcdcdc;
  --unit:8px;
  --shadow-a:0 1px 2px rgba(0,0,0,.06);
  --shadow-b:0 14px 30px rgba(0,0,0,.08);
}

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

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

body{
  margin:0;
  padding-bottom:96px;
  background:var(--paper);
  color:var(--ink);
  font-family:Inter,Helvetica,"Helvetica Neue",Arial,"PingFang SC","Microsoft YaHei",sans-serif;
  font-size:17px;
  line-height:1.62;
  font-weight:400;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}

img,svg{max-width:100%;}
a{color:inherit;}
a:focus-visible{outline:2px solid var(--ink);outline-offset:3px;}

/* 品牌角标 */
.brand{
  position:fixed;
  top:12px;
  left:12px;
  z-index:80;
  width:46px;
  height:46px;
  display:grid;
  place-items:center;
  background:var(--ink);
  color:var(--paper);
  border:1px solid var(--ink);
  border-radius:4px;
  text-decoration:none;
  transition:transform .18s ease;
}
.brand:hover{transform:translateY(-2px);}
.brand-img{display:block;width:44px;height:44px;object-fit:cover;border-radius:3px;background:var(--ink);}
.brand-txt{font-size:18px;font-weight:700;line-height:1;letter-spacing:.04em;}

/* 底部固定导航 */
.dock{
  position:fixed;
  left:0;
  right:0;
  bottom:0;
  z-index:60;
  padding:8px 8px calc(8px + env(safe-area-inset-bottom, 0px));
  background:var(--paper);
  border-top:1px solid var(--ink);
  overflow-x:auto;
  overscroll-behavior-x:contain;
  scrollbar-width:none;
  -webkit-overflow-scrolling:touch;
}
.dock::-webkit-scrollbar{display:none;}
.dock-list{
  display:flex;
  gap:6px;
  margin:0;
  padding:0;
  list-style:none;
  min-width:max-content;
}
.dock-list a{
  display:flex;
  align-items:center;
  gap:8px;
  min-height:44px;
  padding:10px 12px;
  border:1px solid var(--ink);
  border-radius:4px;
  background:var(--paper);
  color:var(--ink);
  text-decoration:none;
  font-size:16px;
  line-height:1.2;
  white-space:nowrap;
  transition:background .16s ease,color .16s ease,transform .16s ease;
}
.dock-list a:hover,
.dock-list a:focus-visible{
  background:var(--ink);
  color:var(--paper);
  transform:translateY(-2px);
}
.dock-list .idx{font-size:13px;font-weight:600;letter-spacing:.06em;opacity:.62;}

@media (min-width:900px){
  .dock{padding:10px 24px calc(10px + env(safe-area-inset-bottom, 0px));}
  .dock-list{min-width:0;justify-content:center;gap:4px;}
  .dock-list a{padding:10px 14px;}
}

/* 首屏 */
.hero{
  display:grid;
  gap:20px;
  padding:88px 16px 32px;
  background:var(--paper);
  border-bottom:1px solid var(--ink);
}
.hero-kicker{
  margin:0;
  font-size:13px;
  font-weight:600;
  letter-spacing:.24em;
}
.hero-title{
  margin:0;
  font-size:clamp(2.9rem, 12.5vw, 8.5rem);
  line-height:.94;
  font-weight:700;
  letter-spacing:-.03em;
  word-break:break-word;
}
.hero-sub{
  margin:0;
  max-width:44ch;
  font-size:17px;
  line-height:1.55;
}
.hero-fig{
  margin:0;
  width:132px;
  justify-self:start;
  padding:8px;
  background:var(--paper);
  border:1px solid var(--ink);
  border-radius:4px;
  box-shadow:var(--shadow-a),var(--shadow-b);
}
.hero-fig svg{display:block;width:100%;height:auto;color:var(--ink);}
.hero-fig figcaption{
  margin-top:6px;
  font-size:13px;
  font-weight:600;
  letter-spacing:.14em;
}

@media (min-width:900px){
  .hero{
    min-height:100svh;
    grid-template-columns:repeat(12,1fr);
    grid-template-rows:auto auto 1fr auto;
    gap:16px;
    padding:112px 32px 40px;
    align-content:start;
  }
  .hero-kicker{grid-column:1 / -1;}
  .hero-title{grid-column:1 / -1;font-size:clamp(4rem, 10.5vw, 9rem);}
  .hero-sub{grid-column:1 / span 6;font-size:19px;}
  .hero-fig{
    grid-column:10 / -1;
    grid-row:3 / 5;
    justify-self:end;
    align-self:end;
    width:200px;
  }
}

/* 斜切色带 */
.band{
  display:block;
  border:0;
  height:16px;
  margin:0;
  background:var(--ink);
  clip-path:polygon(0 0, 100% 0, 100% 42%, 0 100%);
}

/* 正文 + 右侧栏 */
.flow{
  display:grid;
  gap:40px;
  max-width:1200px;
  margin:0 auto;
  padding:40px 16px 56px;
}
@media (min-width:900px){
  .flow{
    grid-template-columns:minmax(0, 1fr) 260px;
    gap:56px;
    padding:56px 32px 72px;
    align-items:start;
  }
  .side{position:sticky;top:88px;}
}

/* 正文排版 */
.content{min-width:0;overflow-wrap:break-word;}
.content > article{
  padding:36px 0;
  border-top:1px solid var(--ink);
  scroll-margin-top:84px;
}
.content > article:first-child{border-top:0;padding-top:0;}
.content h2{
  margin:0 0 12px;
  font-size:clamp(1.5rem, 4.4vw, 2.4rem);
  line-height:1.14;
  font-weight:700;
  letter-spacing:-.02em;
}
.content h2 + hr{
  border:0;
  border-top:1px solid var(--ink);
  margin:0 0 22px;
}
.content h3{
  margin:28px 0 8px;
  font-size:clamp(1.15rem, 3vw, 1.4rem);
  line-height:1.3;
  font-weight:600;
  letter-spacing:-.01em;
}
.content h3 + hr{
  border:0;
  border-top:1px solid var(--ink);
  margin:0 0 14px;
}
.content p{margin:0 0 16px;max-width:68ch;}
.content ul,
.content ol{margin:0 0 18px;padding-left:1.3em;max-width:66ch;}
.content li{margin:0 0 8px;}
.content a{text-decoration:underline;text-underline-offset:3px;text-decoration-thickness:1px;}
.content a:hover{background:var(--ink);color:var(--paper);text-decoration:none;}
.content figure{
  margin:24px 0;
  padding:12px;
  background:var(--paper);
  border:1px solid var(--ink);
  border-radius:4px;
  box-shadow:var(--shadow-a),var(--shadow-b);
}
.content img{display:block;width:100%;height:auto;border-radius:2px;}
.content figcaption{margin-top:8px;font-size:14px;line-height:1.5;opacity:.72;}
.content aside{
  margin:24px 0;
  padding:16px 18px;
  border-left:4px solid var(--ink);
  border-radius:4px;
  background:#f4f4f4;
}
.content aside > :last-child{margin-bottom:0;}
.content blockquote{
  margin:24px 0;
  padding-left:18px;
  border-left:2px solid var(--ink);
  font-size:1.04em;
}
.content time{
  display:inline-block;
  margin:0 0 12px;
  font-size:14px;
  letter-spacing:.08em;
  opacity:.72;
}
.content table{
  width:100%;
  margin:20px 0;
  border-collapse:collapse;
  font-size:16px;
}
.content th,
.content td{
  padding:8px 10px;
  border:1px solid var(--ink);
  text-align:left;
  vertical-align:top;
}
.content th{background:#f4f4f4;font-weight:600;}
.content pre{
  margin:20px 0;
  padding:14px;
  overflow-x:auto;
  border:1px solid var(--ink);
  border-radius:4px;
  font-size:15px;
}

/* 右侧目录 */
.side{
  order:-1;
  padding:18px;
  background:var(--paper);
  border:1px solid var(--ink);
  border-radius:4px;
  box-shadow:var(--shadow-a),var(--shadow-b);
}
.side h2{
  margin:0 0 10px;
  font-size:16px;
  font-weight:700;
  letter-spacing:.2em;
}
.side hr{
  border:0;
  border-top:1px solid var(--ink);
  margin:0 0 12px;
}
.side-list{
  display:grid;
  gap:2px;
  margin:0;
  padding:0;
  list-style:none;
}
.side-list a{
  display:flex;
  align-items:center;
  gap:10px;
  min-height:40px;
  padding:8px 4px;
  border-bottom:1px solid var(--hair);
  font-size:16px;
  line-height:1.35;
  text-decoration:none;
  transition:background .16s ease,color .16s ease,padding .16s ease;
}
.side-list a:hover,
.side-list a:focus-visible{background:var(--ink);color:var(--paper);padding-left:10px;}
.side-list li:last-child a{border-bottom:0;}
.side-list .idx{font-size:13px;font-weight:600;opacity:.55;}

/* 页脚 */
.foot{
  display:grid;
  grid-template-columns:repeat(3, 1fr);
  gap:16px;
  align-items:center;
  max-width:1200px;
  margin:0 auto;
  padding:24px 16px 40px;
  border-top:1px solid var(--ink);
}
.foot-brand{margin:0;font-weight:700;letter-spacing:.06em;}
.foot-copy{grid-column:3;justify-self:end;font-size:14px;opacity:.7;}
@media (min-width:900px){
  .foot{padding:28px 32px 48px;}
}

/* 滚动显现 */
.revealable{
  opacity:0;
  transform:translateY(16px);
  transition:opacity .5s ease,transform .5s ease;
}
.revealable.is-in{opacity:1;transform:none;}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto;}
  *,*::before,*::after{transition:none !important;animation:none !important;}
  .revealable{opacity:1;transform:none;}
}

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