*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  margin:0;
  background:#f5f5f5;
  color:#1f1f1f;
  font-family:Roboto,system-ui,-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  font-size:17px;
  line-height:1.75;
  overflow-x:hidden;
}
img{max-width:100%;display:block}
a{color:#1f1f1f}
h1,h2,h3{font-family:Newsreader,Georgia,"Songti SC","Noto Serif SC",serif;line-height:1.28;margin:0}

/* 顶部 */
.masthead{
  position:sticky;top:0;z-index:60;
  background:rgba(255,255,255,.94);
  -webkit-backdrop-filter:saturate(1.4) blur(10px);
  backdrop-filter:saturate(1.4) blur(10px);
  border-bottom:1px solid #e7e7e7;
}
.mast-in{
  max-width:1180px;margin:0 auto;padding:9px 16px;
  display:grid;grid-template-columns:1fr auto 1fr;
  grid-template-areas:"left brand right";
  align-items:center;gap:10px;
}
.mast-right{grid-area:right;justify-self:end;display:flex;align-items:center;gap:10px}

.drop{grid-area:left;justify-self:start;position:relative}
.drop-r{justify-self:auto}
.drop>summary{
  list-style:none;display:inline-flex;align-items:center;gap:9px;
  min-height:44px;padding:0 16px;border-radius:999px;
  background:#f5f5f5;font-size:16px;cursor:pointer;
  user-select:none;transition:background .18s ease;
}
.drop>summary::-webkit-details-marker{display:none}
.drop>summary:hover{background:#ececec}
.drop>summary::after{
  content:"";width:7px;height:7px;
  border-right:2px solid #1f1f1f;border-bottom:2px solid #1f1f1f;
  transform:rotate(45deg) translateY(-1px);
  transition:transform .2s ease;
}
.drop[open]>summary{background:#1f1f1f;color:#fff}
.drop[open]>summary::after{border-color:#fff;transform:rotate(-135deg) translateY(-1px)}
.drop menu{
  list-style:none;margin:8px 0 0;padding:8px;
  position:absolute;top:100%;left:0;z-index:70;
  min-width:200px;background:#fff;border-radius:16px;
  box-shadow:0 18px 44px rgba(0,0,0,.16);
}
.drop-r menu{left:auto;right:0}
.drop menu a{
  display:flex;align-items:center;min-height:44px;padding:6px 12px;
  border-radius:11px;text-decoration:none;font-size:16px;line-height:1.4;
}
.drop menu a:hover{background:#f5f5f5}

.brand{
  grid-area:brand;justify-self:center;
  font-family:Newsreader,Georgia,"Songti SC",serif;
  font-size:21px;font-weight:600;letter-spacing:.01em;
  text-decoration:none;color:#1f1f1f;
  padding:9px 6px;white-space:nowrap;
}
.cta{
  display:inline-flex;align-items:center;justify-content:center;
  min-height:44px;padding:0 18px;border-radius:999px;
  background:#1f1f1f;color:#fff;text-decoration:none;font-size:16px;
  white-space:nowrap;transition:transform .18s ease,background .18s ease;
}
.cta:hover{background:#000;transform:translateY(-1px)}

/* 首屏 */
.hero{
  position:relative;overflow:hidden;isolation:isolate;
  min-height:45vh;display:flex;align-items:flex-end;
  background:#1f1f1f;border-radius:0 0 26px 26px;
}
.hero-img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;z-index:-3}
.hero::after{
  content:"";position:absolute;inset:0;z-index:-2;
  background:linear-gradient(100deg,rgba(18,18,18,.84) 0%,rgba(18,18,18,.44) 62%,rgba(18,18,18,.62) 100%);
}
.hero-ghost{
  position:absolute;right:-.04em;bottom:-.14em;z-index:-1;
  font-family:Newsreader,Georgia,serif;font-weight:700;
  font-size:clamp(54px,15vw,168px);line-height:.78;
  color:#fff;opacity:.15;white-space:nowrap;pointer-events:none;
}
.hero-in{
  position:relative;width:100%;max-width:1180px;margin:0 auto;
  padding:56px 24px 44px;text-align:right;color:#fff;
}
.hero-in h1{
  font-size:clamp(26px,4.2vw,50px);font-weight:600;letter-spacing:.01em;
  text-shadow:0 2px 20px rgba(0,0,0,.42);
}
.hero-sub{margin:12px 0 0;font-size:17px;line-height:1.6;color:#e8e8e8}

/* 主体 */
.wrap{
  max-width:1180px;margin:0 auto;padding:28px 20px 64px;
  display:grid;grid-template-columns:268px minmax(0,1fr);
  gap:24px;align-items:start;
}
.col{min-width:0}

.rail{
  position:sticky;top:84px;
  background:#fff;border-radius:18px;padding:18px 16px;
  box-shadow:0 4px 6px rgba(0,0,0,.05),0 16px 40px rgba(0,0,0,.04);
}
.rail-h{font-size:18px;font-weight:600;display:flex;align-items:center;gap:9px;margin:0 0 10px}
.rail-h .bar{width:15px;height:3px;border-radius:2px;background:#1f1f1f;display:inline-block}
.rail-list{list-style:none;margin:0;padding:0;counter-reset:rl}
.rail-list li{counter-increment:rl}
.rail-list a{
  display:flex;align-items:center;gap:10px;
  min-height:42px;padding:4px 9px;border-radius:11px;
  text-decoration:none;font-size:16px;line-height:1.4;
  transition:background .18s ease;
}
.rail-list a::before{
  content:counter(rl,decimal-leading-zero);
  font-family:Newsreader,Georgia,serif;font-size:16px;color:#8d8d8d;min-width:20px;
}
.rail-list a:hover{background:#f5f5f5}

.content>section{
  background:#fff;border-radius:18px;
  padding:26px 24px;margin:0 0 18px;
  box-shadow:0 4px 6px rgba(0,0,0,.05),0 14px 34px rgba(0,0,0,.035);
  scroll-margin-top:120px;
  transition:box-shadow .25s ease,transform .25s ease;
}
.content>section:hover{transform:scale(1.006);box-shadow:0 6px 10px rgba(0,0,0,.06),0 18px 44px rgba(0,0,0,.06)}
.content>section:last-child{margin-bottom:0}

.content h2{
  position:relative;padding-left:18px;margin:0 0 14px;
  font-size:26px;font-weight:600;
  display:flex;flex-wrap:wrap;align-items:baseline;gap:8px;
}
.content h2::before{
  content:"";position:absolute;left:0;top:.62em;
  width:8px;height:8px;border-radius:2px;background:#1f1f1f;
}
.content h3{font-size:21px;font-weight:600;margin:22px 0 10px}
.content p{margin:0 0 14px}
.content p:last-child{margin-bottom:0}
.content a{text-decoration:none;border-bottom:1px solid #c9c9c9}
.content a:hover{border-bottom-color:#1f1f1f}
.content ul,.content ol{margin:0 0 14px;padding-left:22px}
.content li{margin:6px 0}
.content blockquote{
  margin:0 0 14px;padding:12px 16px;
  border-left:3px solid #1f1f1f;background:#f5f5f5;border-radius:0 12px 12px 0;
}

/* 页脚 */
.foot{margin-top:34px;background:#fff;border-top:1px solid #e7e7e7}
.foot-cta{
  max-width:1180px;margin:0 auto;padding:40px 20px 26px;
  display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:18px;
}
.foot-cta h2{
  font-size:clamp(24px,3.4vw,38px);font-weight:600;
  display:flex;align-items:center;gap:14px;
}
.foot-cta h2 .bar{width:38px;height:6px;border-radius:3px;background:#1f1f1f}
.btn-top{
  display:inline-flex;align-items:center;justify-content:center;
  min-height:46px;padding:0 22px;border-radius:999px;
  background:#1f1f1f;color:#fff;text-decoration:none;font-size:16px;
  transition:transform .18s ease,background .18s ease;
}
.btn-top:hover{background:#000;transform:translateY(-2px)}

.foot-cols{
  max-width:1180px;margin:0 auto;padding:0 20px 30px;
  display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px;
}
.foot-dl{margin:0;background:#f5f5f5;border-radius:18px;padding:16px 18px}
.foot-dl dt{font-size:16px;font-weight:700;letter-spacing:.05em}
.foot-dl dd{margin:4px 0 0}
.foot-dl dd a{
  display:inline-flex;align-items:center;min-height:40px;
  font-size:16px;text-decoration:none;
}
.foot-dl dd a:hover{text-decoration:underline}

.foot-bar{
  max-width:1180px;margin:0 auto;padding:14px 20px 28px;
  display:flex;flex-wrap:wrap;justify-content:space-between;gap:10px;
  border-top:1px solid #eee;font-size:16px;
}
.foot-bar p{margin:0}
.foot-bar a{text-decoration:none}
.foot-bar a:hover{text-decoration:underline}

/* 滚动显现 */
.js [data-reveal]{opacity:0;transform:translateY(14px);transition:opacity .55s ease,transform .55s ease}
.js [data-reveal].in{opacity:1;transform:none}

@media (max-width:820px){
  .wrap{grid-template-columns:minmax(0,1fr);padding:22px 16px 48px}
  .rail{position:static}
  .rail-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px}
  .foot-cols{grid-template-columns:minmax(0,1fr)}
  .content>section{scroll-margin-top:150px}
}

@media (max-width:760px){
  .mast-in{
    grid-template-columns:auto 1fr auto;
    grid-template-areas:"left brand right" "cta cta cta";
    padding:8px 14px 10px;
  }
  .mast-right{display:contents}
  .drop-l{grid-area:left}
  .drop-r{grid-area:right;justify-self:end}
  .brand{font-size:18px;padding:8px 4px}
  .cta{grid-area:cta;width:100%}
  .drop menu{min-width:172px}
  .hero{min-height:42vh;border-radius:0 0 20px 20px}
  .hero-in{padding:40px 18px 30px}
  .hero-sub{font-size:16px}
  .content>section{padding:22px 18px;border-radius:16px}
  .content h2{font-size:23px}
  .foot-cta{padding:32px 16px 22px}
  .foot-cols{padding:0 16px 24px}
  .foot-bar{padding:14px 16px 26px}
}

@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition-duration:.01ms!important;animation-duration:.01ms!important}
  .js [data-reveal]{opacity:1;transform:none}
  .content>section:hover{transform:none}
}

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