:root{
  --ink:#000;
  --paper:#fff;
  --pad:clamp(1rem,4vw,3rem);
  --max:1440px;
  --line:rgba(0,0,0,.16);
}
*,*::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:'Manrope','Helvetica Neue',Helvetica,Arial,system-ui,sans-serif;
  font-size:17px;
  line-height:1.65;
  font-weight:400;
}
img{display:block;max-width:100%;height:auto}
h1,h2,h3,h4{font-family:'Syne','Helvetica Neue',Helvetica,Arial,sans-serif;font-weight:700;line-height:1.06;letter-spacing:-.02em;margin:0}
p{margin:0 0 1.1rem}
a{color:inherit}
small{font-size:16px}
:focus-visible{outline:3px solid var(--ink);outline-offset:3px}

/* 顶部细条 */
.strip{display:flex;align-items:center;justify-content:space-between;gap:1rem;padding:.6rem var(--pad);border-bottom:1px solid var(--ink)}
.strip .kw{font-family:'Syne',sans-serif;font-size:16px;font-weight:600;letter-spacing:.34em;line-height:1;text-transform:uppercase}

/* 品牌行 */
.brandrow{padding:clamp(.9rem,3vw,1.5rem) var(--pad) clamp(.7rem,2.4vw,1.1rem);border-bottom:2px solid var(--ink)}
.brand{
  display:inline-block;
  text-decoration:none;
  font-family:'Syne',sans-serif;
  font-weight:700;
  font-size:clamp(2rem,8.6vw,4.6rem);
  letter-spacing:-.045em;
  line-height:.95;
}

/* 菜单条 / 全屏遮罩 */
.menu{position:sticky;top:0;z-index:40;background:var(--ink);color:var(--paper);display:flex;align-items:stretch}
.nav{flex:1;min-width:0}
.nav ol{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap}
.nav li+li a{border-left:1px solid rgba(255,255,255,.22)}
.nav a{
  display:flex;align-items:center;min-height:48px;
  padding:.5rem .9rem;
  color:var(--paper);text-decoration:none;font-size:16px;line-height:1.3;white-space:nowrap;
}
.nav a:hover,.nav a:focus-visible{background:var(--paper);color:var(--ink);outline:none}
.burger{
  flex:none;min-height:48px;padding:0 1rem;border:0;border-left:1px solid rgba(255,255,255,.3);
  background:var(--ink);color:var(--paper);font:inherit;font-size:16px;letter-spacing:.12em;cursor:pointer;
}
.burger:hover{background:var(--paper);color:var(--ink)}
.menu-close{display:none}
body.menu-open{overflow:hidden}
body.menu-open .menu{position:fixed;inset:0;z-index:90;flex-direction:column;align-items:stretch;padding:1.2rem var(--pad) 2rem;overflow:auto}
body.menu-open .burger{display:none}
body.menu-open .menu-close{
  display:flex;align-items:center;justify-content:center;align-self:flex-end;
  min-height:44px;padding:0 1.1rem;border:1px solid var(--paper);background:var(--ink);color:var(--paper);
  font:inherit;font-size:16px;letter-spacing:.12em;cursor:pointer;
}
body.menu-open .nav ol{flex-direction:column;margin-top:1.6rem}
body.menu-open .nav li+li a{border-left:0;border-top:1px solid rgba(255,255,255,.24)}
body.menu-open .nav a{
  min-height:64px;padding:.4rem 0;white-space:normal;
  font-family:'Syne',sans-serif;font-weight:700;font-size:clamp(1.4rem,5.5vw,2.1rem);letter-spacing:-.02em;
}
body.menu-open .nav a:hover{background:var(--paper);color:var(--ink)}

/* 首屏 */
.hero{position:relative;overflow:hidden;display:flex;align-items:flex-end;min-height:45vh;background:var(--ink);color:var(--paper)}
.hero-media{position:absolute;inset:0}
.hero-media img{width:100%;height:100%;object-fit:cover;filter:grayscale(1) contrast(1.08)}
.hero::after{
  content:"";position:absolute;inset:0;pointer-events:none;
  background:linear-gradient(96deg,rgba(0,0,0,.94) 12%,rgba(0,0,0,.6) 58%,rgba(0,0,0,.25) 100%);
}
.hero-num{
  position:absolute;right:-.02em;bottom:-.16em;z-index:1;pointer-events:none;
  font-family:'Syne',sans-serif;font-weight:700;font-size:clamp(7rem,28vw,19rem);line-height:.72;letter-spacing:-.06em;
  color:transparent;-webkit-text-stroke:1px rgba(255,255,255,.4);
}
.hero-in{position:relative;z-index:2;width:100%;max-width:60rem;padding:clamp(1.8rem,6vw,3.6rem) var(--pad)}
.hero-in small{display:block;margin-bottom:.8rem;font-family:'Syne',sans-serif;letter-spacing:.34em;color:rgba(255,255,255,.72)}
.hero h1{font-size:clamp(2rem,7.4vw,4.5rem);line-height:.94;letter-spacing:-.04em}
.hero .lead{margin:1rem 0 0;max-width:46ch;font-size:clamp(1rem,2vw,1.12rem);color:rgba(255,255,255,.84)}
@media (prefers-reduced-motion:no-preference){
  .hero-in>*{animation:rise .7s cubic-bezier(.2,.7,.2,1) both}
  .hero-in>*:nth-child(2){animation-delay:.08s}
  .hero-in>*:nth-child(3){animation-delay:.16s}
}
@keyframes rise{from{opacity:0;transform:translateY(18px)}to{opacity:1;transform:none}}

/* 主体栅格 */
main{
  max-width:var(--max);margin:0 auto;
  padding:clamp(2rem,6vw,4rem) var(--pad);
  display:grid;grid-template-columns:minmax(0,1fr);gap:clamp(2rem,5vw,3rem);
  align-items:start;
}
.body{min-width:0}

/* 正文 */
section{counter-reset:sec}
section>div{
  counter-increment:sec;
  scroll-margin-top:96px;
  border-top:2px solid var(--ink);
  padding:clamp(1.6rem,4vw,3rem) 0;
}
section>div::before{
  content:counter(sec,decimal-leading-zero);
  display:block;margin-bottom:.9rem;
  font-family:'Syne',sans-serif;font-size:16px;font-weight:600;letter-spacing:.34em;
}
section h2{font-size:clamp(1.5rem,3.6vw,2.3rem);margin:0 0 .9rem}
section h3{font-size:clamp(1.15rem,2.4vw,1.45rem);margin:1.8rem 0 .6rem}
section h4{font-size:1.05rem;margin:1.4rem 0 .5rem}
section small{
  display:block;margin-bottom:.6rem;
  font-family:'Syne',sans-serif;font-weight:600;font-size:16px;letter-spacing:.22em;
}
section p{max-width:68ch}
section ul,section ol{margin:0 0 1.1rem;padding-left:1.2rem}
section li{margin:.35rem 0}
section a{text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:.22em}
section a:hover{background:var(--ink);color:var(--paper);text-decoration:none}
section blockquote{
  margin:1.4rem 0;padding:.9rem 0 .9rem 1.2rem;
  border-left:6px solid var(--ink);
  font-family:'Syne',sans-serif;font-size:1.02em;
}
section figure{margin:1.4rem 0}
section figcaption{font-size:16px;margin-top:.5rem;color:rgba(0,0,0,.65)}
section table{width:100%;border-collapse:collapse;margin:1.2rem 0;font-size:16px}
section th,section td{border-bottom:1px solid var(--ink);padding:.6rem .5rem;text-align:left;vertical-align:top}
section th{font-family:'Syne',sans-serif;font-weight:700}
section hr{border:0;border-top:1px solid var(--line);margin:1.6rem 0}
section code{font-size:15px;background:#f2f2f2;padding:.1em .3em}

/* 侧栏 */
.side{border-top:2px solid var(--ink);padding-top:1rem}
.side small{display:block;margin-bottom:.5rem;font-family:'Syne',sans-serif;font-weight:600;letter-spacing:.26em}
.side h2{font-size:1.15rem;margin-bottom:1rem}
.side ol{list-style:none;margin:0;padding:0}
.side li{border-bottom:1px solid var(--line)}
.side a{
  display:flex;align-items:center;min-height:44px;padding:.4rem 0;
  text-decoration:none;font-size:16px;
}
.side a:hover{background:var(--ink);color:var(--paper);padding-left:.5rem}

/* 页脚 */
.foot{background:var(--ink);color:var(--paper);margin-top:clamp(2rem,6vw,4rem);padding:clamp(2rem,6vw,3.5rem) var(--pad) 1.5rem}
.foot-cols{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:2rem 1.5rem;max-width:var(--max);margin:0 auto}
.foot dl{margin:0}
.foot dt{font-family:'Syne',sans-serif;font-weight:600;font-size:16px;letter-spacing:.16em;margin-bottom:.8rem}
.foot dd{margin:0 0 .45rem;font-size:16px}
.foot a{display:inline-flex;align-items:center;min-height:40px;color:var(--paper);text-decoration:none;border-bottom:1px solid rgba(255,255,255,.4);line-height:1.3}
.foot a:hover{background:var(--paper);color:var(--ink)}
.fb-name{margin:0 0 .4rem;font-family:'Syne',sans-serif;font-weight:700;font-size:1.25rem;letter-spacing:-.02em}
.fb-host{margin:0;font-size:16px;color:rgba(255,255,255,.64);word-break:break-all}
.copy{max-width:var(--max);margin:2.4rem auto 0;padding-top:1rem;border-top:1px solid rgba(255,255,255,.28);font-size:16px}

/* 入场 */
html.js [data-rv]{opacity:0;transform:translateY(14px)}
html.js [data-rv].in{opacity:1;transform:none;transition:opacity .6s ease,transform .6s cubic-bezier(.2,.7,.2,1)}

/* 断点 */
@media (min-width:900px){
  main{grid-template-columns:minmax(0,7fr) minmax(0,3fr)}
  .side{position:sticky;top:5.4rem}
}
@media (min-width:760px){
  .foot-cols{grid-template-columns:repeat(4,minmax(0,1fr))}
}
@media (max-width:640px){
  .nav a{padding:.5rem .6rem}
  .burger{padding:0 .8rem}
  .hero{min-height:46vh}
  .hero-in{padding-bottom:1.5rem}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .hero-in>*{animation:none}
  html.js [data-rv]{opacity:1;transform:none}
}

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