:root{
  color-scheme:light;
  --bg:#E9EBF8;--bg-panel:#F7F8FE;--bg-panel-2:#DCDFF2;--border:#C9CDE6;
  --accent:#13A37E;--accent-dark:#0A6B54;--text:#141B2E;--text-muted:#596379;
  --success:#1E9E5A;--warn:#C98A12;--error:#D2364F;--coral:#F0607E;--violet:#8B4CE8;--on-accent:#FFFFFF;
  --hero-top:#F2F3FC;--hero-bottom:#E1E4F5;--accent-soft:#D9F1E8;--accent-line:rgba(19,163,126,.55);
  --accent-tint:rgba(19,163,126,.12);--mint-a:rgba(19,163,126,.16);--mint-a2:rgba(19,163,126,.07);
  --mist-a:rgba(201,205,230,.62);--coral-soft:#F9CFD9;--violet-soft:#E0D2FA;--ann-band:#E5E0F8;
  --violet-glow:rgba(139,76,232,.22);--mist-glow:rgba(201,205,230,.45);--glass:rgba(255,255,255,.7);
  --hi-edge:rgba(255,255,255,.92);--line-soft:rgba(201,205,230,.78);--panel-a:rgba(247,248,254,.72);
  --groove-a:rgba(220,223,242,.62);--inset-shade:rgba(20,27,46,.05);--ink-a:rgba(20,27,46,.18);
  --veil:rgba(20,27,46,.28);--clear:transparent;
  --flag-red:#D8283A;--flag-white:#FFFFFF;--flag-blue:#2A3A7E;--flag-edge:rgba(20,27,46,.16);
  --shadow-card:0 44px 80px -36px rgba(19,163,126,.30),0 18px 44px -14px rgba(19,163,126,.12),0 2px 6px rgba(20,27,46,.04);
  --shadow-float:0 26px 52px -20px rgba(19,163,126,.32),0 10px 24px -10px rgba(20,27,46,.10);
  --shadow-soft:0 10px 22px -12px rgba(19,163,126,.40),0 2px 4px rgba(20,27,46,.04);
  --shadow-cta:0 14px 28px -12px rgba(19,163,126,.60),inset 0 1px 0 rgba(255,255,255,.28);
  --shadow-ann:0 12px 26px -16px rgba(139,76,232,.55);
  --shadow-coral:0 24px 56px -30px rgba(240,96,126,.32);
  --shadow-violet:0 24px 56px -30px rgba(139,76,232,.32);
  --font-display:"Inter","Noto Sans SC","PingFang SC","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,monospace;
  --r-card:24px;--r-card-sm:20px;--r-inner:14px;--r-row:12px;--r-btn:12px;--r-pill:999px;--r-small:8px;--r-tiny:4px;--r-circle:50%;
  --wrap:1296px;--gutter:72px;--header-h:72px;--anchor-space:96px;--toc-space:160px;
  --space-1:8px;--space-2:16px;--space-3:24px;--space-4:32px;--space-6:48px;--space-8:64px;
  --text-xs:12px;--text-sm:14px;--text-base:16px;--text-lead:20px;
  --weight-normal:400;--weight-medium:600;--weight-bold:700;--weight-heavy:800;--weight-display:900;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:var(--anchor-space)}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--text-base);line-height:1.6;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
a{color:inherit;text-decoration:none}
p{margin:0}
ul{margin:0;padding:0;list-style:none}
img{max-width:100%;height:auto}
svg{flex-shrink:0}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0;cursor:pointer}
button,a,summary{touch-action:manipulation}
button:disabled{cursor:not-allowed}
:where(a,button,summary,input,select,textarea,[tabindex]):focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:var(--r-small)}
[hidden]{display:none!important}
h1,h2,h3,h4{font-family:var(--font-display);line-height:1.25;text-wrap:balance;margin:0 0 var(--space-3);overflow-wrap:break-word}
h1{font-weight:var(--weight-display);font-size:clamp(52px,4.42vw,64px);letter-spacing:-.02em;line-height:1.1}
h2{font-size:clamp(28px,3vw,40px);font-weight:var(--weight-heavy);letter-spacing:-.02em}
h3{font-size:22px;font-weight:var(--weight-bold)}
code{font-family:var(--font-mono);overflow-wrap:anywhere;font-size:.9em}
pre{max-width:100%;overflow-x:auto;background:var(--bg-panel-2);padding:var(--space-3);border-radius:var(--r-inner)}
pre code{overflow-wrap:normal;white-space:pre}
section[id]{scroll-margin-top:var(--anchor-space)}
body:has(.toc-tabs) section[id]{scroll-margin-top:var(--toc-space)}
.wrap{width:100%;max-width:calc(var(--wrap) + var(--gutter)*2);margin-inline:auto;padding-inline:var(--gutter)}
.wrap>*{min-width:0}
.sec{padding-top:var(--space-8);padding-bottom:var(--space-8)}
.reading-wrap{max-width:880px;margin-inline:auto}
.prose{min-width:0;overflow-wrap:anywhere}
.prose p,.prose ul,.prose ol,.prose blockquote{margin-bottom:var(--space-3)}
.prose ul{padding-left:var(--space-3);list-style:disc}
.prose ol{padding-left:var(--space-3)}
.prose h2,.prose h3{margin-top:var(--space-6)}
.prose a{color:var(--accent-dark);text-decoration:underline;text-underline-offset:4px}
.prose li+li{margin-top:var(--space-1)}
.muted{color:var(--text-muted)}
.mono{font-family:var(--font-mono)}
.no-break{white-space:nowrap}
.vh{position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.ico{fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.skip{position:absolute;left:16px;top:-64px;z-index:100;padding:8px 14px;border-radius:var(--r-btn);background:var(--text);color:var(--bg-panel);font-size:var(--text-sm)}
.skip:focus{top:12px}
.grad{display:inline-block;padding-bottom:.06em;background:linear-gradient(96deg,var(--accent) 4%,var(--violet) 96%);-webkit-background-clip:text;background-clip:text;color:var(--clear)}
.cta-row{display:flex;flex-wrap:wrap;gap:12px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:52px;padding:12px 26px;border-radius:var(--r-btn);font-size:var(--text-base);font-weight:var(--weight-bold);letter-spacing:.01em;flex-shrink:0;white-space:nowrap;transition:transform .2s ease,box-shadow .2s ease,background-color .2s ease}
.btn-main,.btn-primary{background:linear-gradient(135deg,var(--accent),var(--accent-dark));color:var(--on-accent);box-shadow:var(--shadow-cta)}
.btn-main:hover,.btn-primary:hover{transform:translateY(-2px)}
.btn-line,.btn-secondary{background:var(--panel-a);color:var(--text);box-shadow:inset 0 0 0 1.5px var(--border)}
.btn-line:hover,.btn-secondary:hover{box-shadow:inset 0 0 0 1.5px var(--accent);color:var(--accent-dark)}
.btn:active{transform:translateY(0)}
.btn:disabled,.btn[aria-disabled="true"]{opacity:.55;pointer-events:none}
.panel,.card{min-width:0;padding:var(--space-3);border-radius:var(--r-card);background:var(--bg-panel);border:1px solid var(--hi-edge);box-shadow:var(--shadow-soft)}
.panel-inset{padding:var(--space-3);border-radius:var(--r-inner);background:var(--bg-panel-2)}
.badge{display:inline-flex;align-items:center;gap:10px;min-height:32px;padding:4px 14px 4px 12px;border-radius:var(--r-pill);background:var(--panel-a);box-shadow:inset 0 0 0 1px var(--line-soft),var(--shadow-soft);font-size:13px;font-weight:var(--weight-medium);color:var(--text-muted);max-width:100%;overflow:hidden}
.badge .mono{font-weight:var(--weight-bold);color:var(--accent-dark);letter-spacing:.02em}
.live{position:relative;width:8px;height:8px;border-radius:var(--r-circle);background:var(--accent);flex:none}
.live::after{content:"";position:absolute;inset:0;border-radius:inherit;background:var(--accent);animation:ping 2.6s ease-out infinite}
.topbar{position:relative;z-index:60;background:var(--bg-panel);border-bottom:1px solid var(--line-soft)}
.topbar-in{display:flex;align-items:center;height:var(--header-h);gap:16px;flex-wrap:nowrap}
.brand{display:inline-flex;align-items:center;gap:10px;flex:none}
.brand-mark{display:block;width:36px;height:36px}
.brand-word{font-family:var(--font-display);font-weight:var(--weight-heavy);font-size:21px;letter-spacing:-.02em;color:var(--text)}
.brand-zh{font-weight:var(--weight-medium);color:var(--text-muted)}
.nav{margin-left:40px;flex:1;min-width:0}
.nav-list{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:4px}
.nav-list>li>a,.more-btn{position:relative;display:inline-flex;align-items:center;gap:6px;height:40px;padding:0 14px;border-radius:var(--r-small);font-size:15px;font-weight:var(--weight-medium);white-space:nowrap;color:var(--text);transition:background-color .2s,color .2s}
.nav-list>li>a:hover,.more-btn:hover{background:var(--bg);color:var(--accent-dark)}
.nav-list>li>a.is-on,.more-btn.is-on{color:var(--accent-dark)}
.nav-list>li>a.is-on::after{content:"";position:absolute;left:14px;right:14px;bottom:4px;height:2px;border-radius:var(--r-tiny);background:linear-gradient(90deg,var(--accent),var(--violet))}
.caret{font-size:var(--text-xs);color:var(--text-muted)}
.more{position:relative}
.more-menu{position:absolute;top:calc(100% + 10px);left:-12px;width:400px;display:grid;grid-template-columns:1fr 1fr;gap:8px;padding:14px;border-radius:var(--r-card-sm);background:var(--bg-panel);border:1px solid var(--line-soft);box-shadow:var(--shadow-float);z-index:65}
.more-menu[hidden]{display:none}
.mm-head{padding:4px 10px 6px;font-family:var(--font-mono);font-size:11px;letter-spacing:.08em;color:var(--text-muted)}
.mm-group a{display:block;padding:8px 10px;border-radius:var(--r-small)}
.mm-group a:hover{background:var(--bg)}
.mm-group a span{display:block;font-size:var(--text-sm);font-weight:var(--weight-bold)}
.mm-group a small{display:block;font-size:var(--text-xs);color:var(--text-muted);line-height:1.5}
.tools{margin-left:auto;display:flex;align-items:center;gap:10px;flex-shrink:0}
.lang-box{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;width:auto;min-width:44px;height:40px;padding:0 12px;border-radius:var(--r-small);font-size:var(--text-sm);font-weight:var(--weight-medium);color:var(--text-muted);white-space:nowrap}
.lang span{white-space:nowrap}
.lang:hover{background:var(--bg);color:var(--text)}
.lang-panel{position:absolute;right:0;top:calc(100% + 12px);z-index:70;min-width:180px;padding:8px;border:1px solid var(--border);border-radius:var(--r-inner);background:var(--bg-panel);box-shadow:var(--shadow-float)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-small)}
.lang-panel a:hover,.lang-panel a[aria-current]{background:var(--accent-soft);color:var(--accent-dark)}
.login{display:inline-flex;align-items:center;justify-content:center;gap:8px;height:40px;padding:0 18px;border-radius:var(--r-btn);background:var(--accent-soft);color:var(--accent-dark);font-size:15px;font-weight:var(--weight-bold);white-space:nowrap;box-shadow:inset 0 0 0 1px var(--accent-line);transition:background-color .2s,box-shadow .2s}
.login:hover{background:var(--bg-panel);box-shadow:inset 0 0 0 1.5px var(--accent)}
.burger{display:none;align-items:center;justify-content:center;flex-direction:column;gap:4px;min-width:44px;min-height:44px;border-radius:var(--r-small);color:var(--text)}
.burger-line{display:block;width:20px;height:2px;background:currentColor;border-radius:var(--r-tiny)}
.nav-drawer{display:none}
.nav-veil{display:none}
html.nav-open{overflow:hidden}
.ann{position:relative;z-index:20;height:40px;background:var(--ann-band)}
.ann-x:checked+.ann{display:none}
.ann-cap{position:absolute;top:0;left:50%;transform:translateX(-50%);min-width:640px;height:52px;padding:0 32px 4px;display:flex;align-items:center;justify-content:center;gap:16px;border-radius:0 0 28px 28px;background:linear-gradient(90deg,var(--coral-soft),var(--violet-soft));box-shadow:var(--shadow-ann);white-space:nowrap}
.ann-dot{width:8px;height:8px;border-radius:var(--r-circle);background:var(--accent);box-shadow:0 0 0 4px var(--hi-edge);flex-shrink:0}
.ann-text{font-size:var(--text-sm);font-weight:var(--weight-medium)}
.ann-text strong{font-weight:var(--weight-heavy)}
.ann-sep{margin:0 10px;color:var(--text-muted)}
.ann-link{display:inline-flex;align-items:center;justify-content:center;min-height:30px;padding:0 14px;border-radius:var(--r-pill);font-size:13px;font-weight:var(--weight-bold);background:var(--hi-edge);box-shadow:inset 0 0 0 1px var(--ink-a)}
.ann-close{position:absolute;right:24px;top:6px;width:28px;height:28px;display:inline-flex;align-items:center;justify-content:center;border-radius:var(--r-circle);cursor:pointer}
.ann-close:hover{background:var(--hi-edge)}
.ann-x:focus-visible+.ann .ann-close{outline:2px solid var(--accent);outline-offset:2px}
.site-footer{background:var(--bg-panel-2);border-top:1px solid var(--border);padding-top:56px;padding-bottom:32px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:48px}
.footer-brand p{margin-top:16px;max-width:30em;color:var(--text-muted)}
.footer-title{font-size:var(--text-sm);font-weight:var(--weight-heavy);margin-bottom:16px}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px 16px}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:28px;font-size:var(--text-sm)}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{color:var(--accent-dark);text-decoration:underline}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 24px;margin-top:32px;padding-top:24px;border-top:1px solid var(--border)}
.footer-bottom{display:flex;flex-wrap:wrap;justify-content:space-between;gap:16px;margin-top:24px;color:var(--text-muted);font-size:var(--text-sm)}
.footer-legal{display:flex;flex-wrap:wrap;gap:24px}
.reveal{transition:opacity .35s ease,transform .35s ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-height:120px;overflow:hidden;max-width:100%;margin-block:24px}
#server-status+*{margin-top:24px}
@keyframes ping{0%{transform:scale(1);opacity:.5}100%{transform:scale(2.8);opacity:0}}
@keyframes bob{0%,100%{transform:translateY(0)}50%{transform:translateY(-6px)}}
@keyframes breathe{0%,100%{opacity:.28}50%{opacity:.4}}
@media(min-width:1101px){
  .more:hover .more-menu:not([data-controlled]){display:grid}
}
@media(max-width:1250px){
  :root{--gutter:40px}
  .nav{margin-left:16px}
  .nav-list>li>a,.more-btn{padding-inline:10px}
}
@media(max-width:1100px){
  :root{--gutter:32px}
  .nav{display:none}
  .tools{margin-left:auto}
  .burger{display:flex}
  .nav-drawer{position:fixed;top:var(--header-h);right:0;left:0;height:calc(100dvh - var(--header-h));max-height:calc(100dvh - var(--header-h));overflow-y:auto;overscroll-behavior:contain;background:var(--bg-panel);padding:24px var(--gutter) 48px;z-index:55;border-top:1px solid var(--border)}
  .nav-drawer:not([hidden]){display:block}
  .nav-drawer a{display:flex;width:100%;align-items:center;min-height:48px;padding:12px 16px;border-radius:var(--r-row);font-weight:var(--weight-medium)}
  .nav-drawer a:hover,.nav-drawer a.is-on{background:var(--accent-soft);color:var(--accent-dark)}
  .drawer-languages{border-top:1px solid var(--border);margin-top:16px;padding-top:16px}
  .nav-veil:not([hidden]){display:block;position:fixed;inset:var(--header-h) 0 0;background:var(--veil);z-index:50}
  .footer-grid{gap:24px}
}
@media(max-width:768px){
  :root{--gutter:24px}
  h1{font-size:clamp(28px,6vw,40px)}
  h2{font-size:28px}
  .sec{padding-top:48px;padding-bottom:48px}
  .footer-grid{grid-template-columns:1fr 1fr}
  .footer-brand{grid-column:1/-1}
}
@media(max-width:640px){
  :root{--gutter:16px;--header-h:64px;--anchor-space:80px;--toc-space:144px}
  .no-break{white-space:normal}
  .tilt{transform:none}
  .topbar-in{gap:8px}
  .brand{gap:6px}
  .brand-mark{width:28px;height:28px}
  .brand-word{font-size:18px}
  .tools{gap:4px;margin-left:auto}
  .lang{font-size:11px;padding-inline:6px}
  .login{font-size:13px;padding-inline:12px}
  .ann{height:44px}
  .ann-cap{min-width:0;width:calc(100% - 16px);height:52px;padding:0 10px 4px;gap:8px;border-radius:0 0 var(--r-card-sm) var(--r-card-sm)}
  .ann-text{font-size:11px}
  .ann-sep{margin-inline:3px}
  .ann-link{display:none}
  .ann-close{position:static;flex-shrink:0}
  .ann-dot{width:6px;height:6px;box-shadow:none}
  .footer-grid{grid-template-columns:1fr}
  .footer-brand{grid-column:auto}
  .btn{padding-inline:20px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation:none!important;transition:none!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}