:root {
  --c-bg:#FFFFFF;
  --c-panel:#F5F6F8;
  --c-panel-2:#ECEEF2;
  --c-border:#E4E6EB;
  --c-accent:#6A4CFF;
  --c-accent-dark:#4B2FD6;
  --c-text:#16171D;
  --c-muted:#676B78;
  --c-success:#1FA971;
  --c-warn:#D9950F;
  --c-error:#E5484D;
  --c-white:#FFFFFF;
  --c-accent-tint:#EFEBFF;
  --c-success-ring:rgba(31,169,113,.16);
  --c-success-ink:#126B48;
  --c-warn-ink:#805708;
  --c-error-ink:#AD252A;
  --c-success-bg:#EAF7F1;
  --c-warn-bg:#FFF5DD;
  --c-error-bg:#FFF0F0;
  --c-clear:rgba(236,238,242,0);
  --c-veil:rgba(22,23,29,.28);
  --c-term:#1A1B23;
  --c-term-bar:#22232D;
  --c-term-text:#E7E8EE;
  --c-term-muted:#A4A8B6;
  --c-term-dot:#454755;
  --c-term-prompt:#A899FF;
  --c-tux-body-1:#9481FF;
  --c-tux-body-2:#5B3CF0;
  --c-tux-body-3:#2F1C9E;
  --c-tux-belly-1:#FFFFFF;
  --c-tux-belly-2:#E2DEF3;
  --c-tux-beak-1:#FFC45E;
  --c-tux-beak-2:#EF7A1C;
  --c-bubble-1:#F3F0FF;
  --c-bubble-2:#DCD3FF;
  --grad-accent:linear-gradient(135deg,var(--c-accent),var(--c-accent-dark));
  --grad-tray:radial-gradient(120% 80% at 76% 100%,var(--c-panel-2),var(--c-clear) 62%);
  --grad-bubble:radial-gradient(circle at 30% 24%,var(--c-white),var(--c-bubble-1) 42%,var(--c-bubble-2));
  --font-display:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans GB','Microsoft YaHei',system-ui,sans-serif;
  --font-body:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans GB','Microsoft YaHei',system-ui,sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,'SFMono-Regular',Menlo,Consolas,'Liberation Mono',monospace;
  --fs-xs:12.5px;
  --fs-sm:14.5px;
  --fs-body:16px;
  --fs-lede:16.5px;
  --fs-h1:clamp(34px,2.4vw + 13px,48px);
  --fs-h2:clamp(24px,1.2vw + 18px,36px);
  --fs-h3:22px;
  --weight-normal:400;
  --weight-medium:500;
  --r-tray:32px;
  --r-card:22px;
  --r-window:18px;
  --r-term:16px;
  --r-menu:18px;
  --r-field:9px;
  --r-item:12px;
  --r-icon:11px;
  --r-line:2px;
  --r-pill:999px;
  --r-round:50%;
  --gutter:40px;
  --content-width:1296px;
  --reading-width:800px;
  --nav-h:76px;
  --peek:52px;
  --space-section:112px;
  --ease:180ms ease;
  --shadow-window:0 0 0 1px rgba(22,23,29,.04),0 2px 4px rgba(22,23,29,.04),0 18px 36px -12px rgba(22,23,29,.14),0 56px 96px -32px rgba(52,36,150,.26);
  --shadow-term:0 2px 6px rgba(22,23,29,.18),0 24px 48px -16px rgba(22,23,29,.42),0 48px 80px -40px rgba(52,36,150,.35);
  --shadow-float:0 0 0 1px rgba(22,23,29,.03),0 1px 2px rgba(22,23,29,.06),0 14px 32px -10px rgba(22,23,29,.18);
  --shadow-bubble:0 0 0 1px rgba(22,23,29,.04),0 4px 10px rgba(22,23,29,.08),0 18px 34px -12px rgba(52,36,150,.4);
  --shadow-btn:0 1px 2px rgba(75,47,214,.25),0 14px 26px -12px rgba(75,47,214,.62);
  --shadow-chip:0 0 0 1px rgba(22,23,29,.06),0 2px 6px rgba(22,23,29,.05);
  --shadow-seg:0 0 0 1px rgba(22,23,29,.04),0 14px 34px -14px rgba(22,23,29,.18);
  --shadow-menu:0 0 0 1px rgba(22,23,29,.05),0 20px 44px -16px rgba(22,23,29,.22);
  --shadow-card:0 0 0 1px rgba(22,23,29,.04),0 16px 40px -18px rgba(22,23,29,.2);
  --shadow-knob:0 1px 2px rgba(22,23,29,.22);
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:24px}
html.nav-open{overflow:hidden}
body{margin:0;background:var(--c-bg);color:var(--c-text);font-family:var(--font-body);font-size:var(--fs-body);line-height:1.6;-webkit-font-smoothing:antialiased}
main,section,article,aside,nav,div,li{min-width:0}
img,svg{max-width:100%;vertical-align:middle}
img{height:auto}
svg{display:block}
a{color:var(--c-accent-dark);text-decoration:none;text-underline-offset:4px}
a:hover{text-decoration:underline}
button,input,select,textarea{font:inherit}
button{color:inherit;cursor:pointer}
button{border:0;padding:0;background:none}
button:disabled{cursor:not-allowed}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--c-accent);outline-offset:3px}
h1,h2,h3{font-family:var(--font-display);font-weight:var(--weight-normal);line-height:1.18;letter-spacing:-.02em;text-wrap:balance}
h1{font-size:var(--fs-h1);line-height:1.1}
h2{font-size:var(--fs-h2)}
h3{font-size:var(--fs-h3)}
p{margin-top:0}
strong{font-weight:var(--weight-medium)}
code{font-family:var(--font-mono);font-size:.9em;overflow-wrap:anywhere}
pre{max-width:100%;min-width:0;overflow-x:auto;padding:24px;border-radius:var(--r-term);background:var(--c-term);color:var(--c-term-text);line-height:1.8}
pre code{font-size:var(--fs-sm);white-space:pre;overflow-wrap:normal;word-break:normal}
.wrap{width:100%;max-width:calc(var(--content-width) + var(--gutter)*2);margin-inline:auto;padding-inline:var(--gutter)}
.reading{max-width:calc(var(--reading-width) + var(--gutter)*2)}
.section{padding-top:var(--space-section);padding-bottom:var(--space-section)}
.section-heading{margin-top:0;margin-bottom:36px}
.nowrap{white-space:nowrap}
.muted{color:var(--c-muted)}
.kw{color:var(--c-accent)}
.skip{position:absolute;left:16px;top:-80px;z-index:100;padding:10px 16px;border-radius:var(--r-pill);background:var(--c-text);color:var(--c-white);font-size:var(--fs-sm)}
.skip:focus{top:12px}
.cta{display:flex;flex-wrap:wrap;gap:12px;margin-top:30px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:52px;padding:12px 26px;border-radius:var(--r-pill);font-size:var(--fs-body);font-weight:var(--weight-medium);line-height:1.4;text-align:center;transition:transform var(--ease),background var(--ease)}
.btn svg{width:16px;height:16px;flex-shrink:0}
.btn:hover{text-decoration:none}
.btn-primary{background:var(--grad-accent);color:var(--c-white);box-shadow:var(--shadow-btn)}
.btn-primary:hover,.btn-primary.is-hover{transform:translateY(-1px);background:var(--c-accent-dark);color:var(--c-white)}
.btn-ghost{background:var(--c-white);color:var(--c-text);border:1px solid var(--c-border)}
.btn-ghost:hover,.btn-ghost.is-hover{background:var(--c-panel);color:var(--c-text)}
.btn:active,.btn.is-active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--c-panel-2);color:var(--c-muted);box-shadow:none;transform:none}
.btn.is-focus{outline:2px solid var(--c-accent);outline-offset:3px}
.pill-link{display:inline-flex;align-items:center;gap:8px;margin-top:28px;min-height:42px;padding:8px 18px;border-radius:var(--r-pill);border:1px solid var(--c-border);background:var(--c-white);color:var(--c-accent-dark);font-size:var(--fs-sm)}
.pill-link:hover{background:var(--c-accent-tint);color:var(--c-accent-dark);text-decoration:none}
.card{padding:32px;border-radius:var(--r-card);background:var(--c-white);color:var(--c-text);box-shadow:var(--shadow-card)}
.card h3{margin-top:0}
.surface{padding:48px;border-radius:var(--r-tray);background:var(--c-panel);color:var(--c-text)}
.card-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:24px}
.prose{line-height:1.85}
.prose h2{margin-top:72px}
.prose h3{margin-top:40px}
.prose p,.prose ul,.prose ol{margin-bottom:24px}
.prose a{text-decoration:underline}
.prose li+li{margin-top:8px}
.reveal{opacity:1;transform:none}
.reveal-pending .reveal:not(.shown){opacity:0;transform:translateY(18px)}
.reveal{transition:opacity 600ms ease,transform 600ms ease}
.reveal.shown{opacity:1;transform:none}
/* 页头使用独立的宽版心，不复用阅读版心。 */
.topbar{position:relative;z-index:40;height:var(--nav-h);background:var(--c-bg);color:var(--c-text)}
.topbar-in{width:100%;max-width:min(100%,calc(1280px + var(--gutter)*2));height:100%;margin-inline:auto;padding-inline:var(--gutter);display:flex;align-items:center;gap:36px}
.brand{display:inline-flex;align-items:center;gap:10px;font-size:17px;font-weight:var(--weight-medium);letter-spacing:-.01em;white-space:nowrap;color:var(--c-text);flex-shrink:0}
.brand:hover{text-decoration:none}
.brand-mark{width:34px;height:34px;flex-shrink:0}
.desktop-nav{min-width:0}
.nav-list{display:flex;align-items:center;gap:2px;list-style:none;margin:0;padding:0}
.nav-link{display:inline-flex;align-items:center;gap:6px;min-height:38px;padding:8px 14px;border-radius:var(--r-pill);font-size:15px;line-height:1.4;color:var(--c-text);white-space:nowrap}
.nav-link:hover{background:var(--c-panel);color:var(--c-text);text-decoration:none}
.nav-link[aria-current="page"],.nav-link.is-current{background:var(--c-accent-tint);color:var(--c-accent-dark)}
.nav-link svg{width:12px;height:12px;flex-shrink:0;color:var(--c-muted)}
.more,.language-picker{position:relative}
.more-menu,.language-menu{position:absolute;top:calc(100% + 10px);left:-6px;min-width:248px;margin:0;padding:8px;list-style:none;background:var(--c-white);color:var(--c-text);border-radius:var(--r-menu);box-shadow:var(--shadow-menu)}
.language-menu{left:auto;right:0;min-width:190px}
.more-menu a,.language-menu a{display:block;min-height:44px;padding:10px 14px;border-radius:var(--r-item);color:var(--c-text)}
.more-menu a:hover,.language-menu a:hover{background:var(--c-panel);color:var(--c-text);text-decoration:none}
.more-menu a[aria-current="page"],.language-menu a[aria-current="true"]{background:var(--c-accent-tint);color:var(--c-accent-dark)}
.mm-title{display:block;font-size:var(--fs-sm)}
.mm-desc{display:block;font-size:var(--fs-xs);color:var(--c-muted);margin-top:2px}
.topbar-right{margin-left:auto;display:flex;align-items:center;gap:12px;flex-shrink:0}
.lang{display:inline-flex;align-items:center;gap:8px;min-height:40px;padding:8px 16px 8px 14px;border-radius:var(--r-pill);border:1px solid var(--c-border);background:var(--c-white);color:var(--c-text);font-size:var(--fs-sm);white-space:nowrap}
.lang:hover{background:var(--c-panel);color:var(--c-text)}
.lang svg{width:16px;height:16px;flex-shrink:0;color:var(--c-muted)}
.lang-short{display:none}
.lang-caret{color:var(--c-muted);font-size:var(--fs-xs)}
.menu-toggle{display:none;min-width:44px;min-height:44px;border-radius:var(--r-round);background:var(--c-panel);color:var(--c-text);place-items:center}
.menu-toggle svg{width:22px;height:22px}
.mobile-drawer{position:absolute;top:var(--nav-h);left:0;right:0;padding:16px var(--gutter) 28px;background:var(--c-white);color:var(--c-text);max-height:calc(100dvh - var(--nav-h));overflow-y:auto;overscroll-behavior:contain;box-shadow:var(--shadow-menu)}
.mobile-drawer ul{list-style:none;margin:0;padding:0}
.mobile-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;border-radius:var(--r-item);color:var(--c-text)}
.mobile-drawer a:hover,.mobile-drawer a[aria-current]{background:var(--c-accent-tint);color:var(--c-accent-dark);text-decoration:none}
.drawer-heading{margin:20px 16px 8px;font-size:var(--fs-xs);color:var(--c-muted)}
.nav-veil{position:fixed;inset:var(--nav-h) 0 0;z-index:35;background:var(--c-veil);color:var(--c-text);cursor:pointer}
.static-more{list-style:none}
.static-more summary{list-style:none;cursor:pointer}
.static-more summary::-webkit-details-marker{display:none}
.site-footer{margin-top:64px;padding-top:72px;padding-bottom:32px;background:var(--c-panel);color:var(--c-text)}
.footer-grid{display:grid;grid-template-columns:1.25fr .8fr 1.3fr .8fr;gap:48px}
.footer-intro p{margin-top:20px;max-width:26em;color:var(--c-muted);font-size:var(--fs-sm)}
.footer-title{margin:0 0 16px;font-size:var(--fs-body);font-weight:var(--weight-medium)}
.footer-links{list-style:none;margin:0;padding:0}
.footer-links a{display:inline-block;padding-block:5px;color:var(--c-muted);font-size:var(--fs-sm)}
.footer-links a:hover{color:var(--c-accent-dark)}
.footer-bottom{display:flex;flex-wrap:wrap;justify-content:space-between;gap:16px;margin-top:56px;padding-top:24px;border-top:1px solid var(--c-border);font-size:var(--fs-xs);color:var(--c-muted)}
.footer-legal{display:flex;flex-wrap:wrap;gap:24px}
.footer-legal a{color:var(--c-muted)}
@media(max-width:1279px){
  .topbar-in{gap:24px}
  .desktop-nav{display:none}
  .menu-toggle{display:grid}
  .topbar-right{margin-left:auto}
}
@media(min-width:1280px){
  .mobile-drawer,.nav-veil{display:none!important}
}
@media(max-width:900px){
  :root{--gutter:32px;--space-section:80px}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:768px){
  :root{--fs-h1:clamp(24px,4vw,30px)}
}
@media(max-width:640px){
  :root{--gutter:20px;--space-section:64px}
  .topbar-in{gap:10px}
  .brand{font-size:var(--fs-sm);gap:7px}
  .brand-mark{width:30px;height:30px}
  .topbar-right{gap:6px;margin-left:auto}
  .lang{padding-inline:12px}
  .lang-full{display:none}
  .lang-short{display:inline}
  .lang svg{display:none}
  .card-grid,.footer-grid{grid-template-columns:minmax(0,1fr)}
  .surface{padding:28px 20px}
  .card{padding:24px}
  .tilt,.stage,[data-tilt]{transform:none!important}
  .footer-grid{gap:32px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation:none!important;transition:none!important}
  .reveal-pending .reveal:not(.shown){opacity:1;transform:none}
}