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

:root{
  --red:#ff0000;
  --violet:#8b00ff;
  --ink:#261717;
  --paper:#f8f1f1;
  --muted:rgba(255,255,255,.72);
  --glass:rgba(255,255,255,.10);
  --glass-strong:rgba(255,255,255,.16);
  --line:rgba(255,255,255,.20);
  --line-soft:rgba(255,255,255,.12);
  --shadow:0 18px 44px rgba(10,3,3,.45);
  --r:4px;
  --font-head:"Poppins","Open Sans",system-ui,-apple-system,"PingFang SC","Microsoft YaHei",sans-serif;
  --font-body:"Open Sans",system-ui,-apple-system,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
}

*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;background:#1d1212;color:var(--paper);font-family:var(--font-body);font-size:17px;line-height:1.72;overflow-x:hidden}
h1,h2,h3,h4{font-family:var(--font-head);line-height:1.22;color:#fff}
p{margin:0 0 14px}
img{max-width:100%}
a{color:#ff9a9a}
:focus-visible{outline:2px solid var(--red);outline-offset:2px}

.bgfx{
  position:fixed;inset:-12% -12% -12% -12%;z-index:-1;pointer-events:none;will-change:transform;
  background:
    radial-gradient(42vw 42vw at 10% 2%,rgba(255,0,0,.62),transparent 62%),
    radial-gradient(52vw 52vw at 92% 8%,rgba(139,0,255,.58),transparent 64%),
    radial-gradient(46vw 46vw at 46% 106%,rgba(139,0,255,.42),transparent 62%),
    linear-gradient(165deg,#301c1c 0%,#261717 52%,#1a1010 100%);
}
.bgfx::after{
  content:"";position:absolute;inset:0;
  background:radial-gradient(30vw 30vw at 70% 42%,rgba(255,255,255,.12),transparent 70%);
  animation:drift 18s ease-in-out infinite alternate;
}
@keyframes drift{
  from{transform:translate3d(-3%,-2%,0) scale(1)}
  to{transform:translate3d(4%,3%,0) scale(1.12)}
}

/* 顶栏 */
.topbar{
  position:sticky;top:0;z-index:30;
  display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:12px;
  padding:10px clamp(12px,3vw,32px);
  background:rgba(30,18,18,.55);
  border-bottom:1px solid var(--line);
  backdrop-filter:blur(18px) saturate(150%);
  -webkit-backdrop-filter:blur(18px) saturate(150%);
}
.topnav ul{display:flex;flex-wrap:wrap;gap:2px;margin:0;padding:0;list-style:none}
.topnav--right ul{justify-content:flex-end}
.topnav a{
  display:inline-flex;align-items:center;min-height:44px;padding:0 11px;border-radius:var(--r);
  color:rgba(255,255,255,.85);text-decoration:none;
  font-family:var(--font-head);font-size:.92rem;font-weight:500;
  transition:background .25s,color .25s;
}
.topnav a:hover{background:var(--glass-strong);color:#fff}
.brand{
  display:inline-flex;align-items:center;gap:8px;padding:7px 15px;
  border:1px solid var(--line);border-radius:var(--r);
  background:var(--glass);box-shadow:var(--shadow);
  backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);
  color:#fff;text-decoration:none;font-family:var(--font-head);font-weight:700;letter-spacing:.04em;
}
.brand-name{white-space:nowrap}
.brand-mark{display:block;height:24px;width:auto}
.topbar-end{display:flex;align-items:center;justify-content:flex-end;gap:10px}
.search{display:flex;align-items:center;gap:6px}
.search input{
  min-height:40px;width:120px;padding:0 10px;border:1px solid var(--line);border-radius:var(--r);
  background:rgba(255,255,255,.09);color:#fff;font:inherit;font-size:.9rem;
  backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);
}
.search input::placeholder{color:rgba(255,255,255,.6)}
.search button{
  min-height:40px;padding:0 14px;border:1px solid rgba(255,255,255,.28);border-radius:var(--r);
  background:linear-gradient(100deg,rgba(255,0,0,.88),rgba(139,0,255,.88));
  color:#fff;font-family:var(--font-head);font-size:.9rem;font-weight:600;cursor:pointer;
}

/* 左侧栏 + 主区 */
.shell{
  display:grid;grid-template-columns:230px minmax(0,1fr);
  gap:clamp(16px,3vw,38px);
  max-width:1340px;margin:0 auto;
  padding:clamp(14px,3vw,34px) clamp(12px,3vw,32px) 0;
}
.rail{position:sticky;top:86px;align-self:start}
.rail-list{
  display:grid;gap:2px;margin:0;padding:10px;list-style:none;
  border:1px solid var(--line);border-radius:var(--r);
  background:var(--glass);box-shadow:var(--shadow);
  backdrop-filter:blur(16px) saturate(140%);-webkit-backdrop-filter:blur(16px) saturate(140%);
}
.rail a{
  display:flex;align-items:center;min-height:44px;padding:6px 12px;border-radius:var(--r);
  color:rgba(255,255,255,.8);text-decoration:none;font-size:.94rem;
  transition:background .25s,color .25s;
}
.rail a:hover,.rail a[aria-current="true"]{
  background:linear-gradient(100deg,rgba(255,0,0,.42),rgba(139,0,255,.34));color:#fff;
}
main{min-width:0}

/* 首屏 */
.hero{
  display:grid;grid-template-columns:minmax(0,1.05fr) minmax(0,.95fr);
  gap:clamp(18px,3vw,38px);align-items:center;
  min-height:calc(100vh - 130px);
  padding:clamp(16px,3vw,34px) 0 clamp(24px,4vw,48px);
}
.hero-copy h1{
  margin:0 0 26px;font-size:clamp(2rem,5vw,3.5rem);font-weight:700;letter-spacing:-.015em;
  text-shadow:0 10px 30px rgba(0,0,0,.35);
}
.hero-actions{display:flex;flex-wrap:wrap;gap:12px}
.cta{
  display:inline-flex;align-items:center;min-height:50px;padding:0 26px;border-radius:var(--r);
  background:linear-gradient(100deg,var(--red),var(--violet));color:#fff;text-decoration:none;
  font-family:var(--font-head);font-weight:600;
  box-shadow:0 16px 34px rgba(139,0,255,.38);
  transition:transform .25s,box-shadow .25s;
}
.cta:hover{transform:translateY(-2px);box-shadow:0 22px 40px rgba(255,0,0,.34)}
.hero-media{
  position:relative;overflow:hidden;aspect-ratio:4/3;
  border:1px solid var(--line);border-radius:var(--r);
  background:var(--glass);box-shadow:var(--shadow);
  backdrop-filter:blur(15px);-webkit-backdrop-filter:blur(15px);
}
.hero-media img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;opacity:0;transition:opacity .9s ease}
.hero-media img.is-on{opacity:1}
.hero-glare{
  position:absolute;inset:0;z-index:3;pointer-events:none;
  background:linear-gradient(135deg,rgba(255,255,255,.32),rgba(255,255,255,0) 46%,rgba(139,0,255,.22));
}
.hero-media--plain{background:linear-gradient(140deg,rgba(255,0,0,.45),rgba(139,0,255,.42) 60%,rgba(255,255,255,.14))}

/* 正文 */
.article{padding-bottom:clamp(20px,4vw,40px)}
.article > div{padding:clamp(20px,4vw,42px) 0;border-top:1px solid var(--line-soft)}
.article > div.hero{border-top:0;padding-top:0}
.article [id]{scroll-margin-top:120px}
.subtitle{margin:6px 0 0;color:var(--muted);font-size:1rem;max-width:62ch}
.preamble h2{margin:0;font-size:clamp(1.4rem,3.2vw,2rem)}
.article h2{margin:0 0 10px;font-size:clamp(1.32rem,2.8vw,1.85rem)}
.article h2 + p{color:var(--muted);margin-top:-2px}
.article h3{margin:26px 0 8px;font-size:1.14rem}
.article p{max-width:70ch}
.article ul,.article ol{padding-left:1.25em;margin:0 0 16px;max-width:70ch}
.article li{margin:.4em 0}
.article a{color:#ff9a9a;text-underline-offset:2px}
.article a:hover{color:#fff}
.article img{border:1px solid var(--line);border-radius:var(--r);height:auto}
.article figure{margin:18px 0}
.article blockquote{
  margin:18px 0;padding:14px 18px;border-left:3px solid var(--violet);border-radius:var(--r);
  background:var(--glass);color:rgba(255,255,255,.86);max-width:70ch;
  backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);
}
.article code{font-size:.92em;padding:.1em .35em;border-radius:3px;background:rgba(255,255,255,.12)}
.article pre{overflow-x:auto;padding:14px;border-radius:var(--r);border:1px solid var(--line);background:rgba(0,0,0,.35)}
.article table{display:block;overflow-x:auto;width:100%;border-collapse:collapse;font-size:.96rem}
.article th,.article td{border:1px solid var(--line);padding:10px 12px;text-align:left}

/* 页脚 */
.foot{
  max-width:1340px;margin:clamp(24px,4vw,52px) auto 0;
  padding:clamp(20px,4vw,38px) clamp(12px,3vw,32px) 22px;
  display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr);gap:22px 30px;
  border-top:1px solid var(--line);background:rgba(255,255,255,.055);
  backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);
}
.foot-name{margin:0 0 6px;font-family:var(--font-head);font-size:1.08rem;font-weight:700;color:#fff;letter-spacing:.02em}
.foot-desc{margin:0;color:var(--muted);font-size:.94rem;max-width:46ch}
.foot-links ul{display:flex;flex-wrap:wrap;gap:2px 6px;margin:0;padding:0;list-style:none;justify-content:flex-end}
.foot-links a{
  display:inline-flex;align-items:center;min-height:40px;padding:0 10px;border-radius:var(--r);
  color:rgba(255,255,255,.8);text-decoration:none;font-size:.92rem;
}
.foot-links a:hover{background:var(--glass);color:#fff}
.foot-bar{
  grid-column:1/-1;display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;
  gap:8px;padding-top:14px;border-top:1px solid var(--line-soft);
}
.copy{margin:0;font-size:.86rem;color:rgba(255,255,255,.6)}
.totop{
  display:inline-flex;align-items:center;min-height:40px;padding:0 12px;
  border:1px solid var(--line);border-radius:var(--r);
  color:rgba(255,255,255,.85);text-decoration:none;font-size:.88rem;
}
.totop:hover{background:var(--glass-strong);color:#fff}

@media (max-width:980px){
  .topbar{grid-template-columns:1fr;gap:6px;padding:8px 12px}
  .brand{order:-1;justify-self:center}
  .topnav ul{justify-content:center}
  .topbar-end{flex-direction:column;justify-content:center;width:100%}
  .search{width:100%}
  .search input{flex:1;width:auto}
  .shell{grid-template-columns:1fr;padding-top:14px}
  .rail{display:none}
  .hero{grid-template-columns:1fr;min-height:0;padding:12px 0 24px}
  .hero-copy h1{margin-bottom:18px}
  .hero-media{aspect-ratio:16/10}
  .foot{grid-template-columns:1fr}
  .foot-links ul{justify-content:flex-start}
}
@media (max-width:520px){
  .topnav a{font-size:.85rem;padding:0 8px}
  .search button{padding:0 12px}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .bgfx::after{animation:none}
  *{transition-duration:.01ms !important}
}

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