:root{
 --bg:#FAF9FA;--bg-panel:#FFFFFF;--bg-panel-2:#F2F1F4;--border:#E6E4EA;
 --accent:#3A5BFF;--accent-dark:#2340D9;--accent-sky:#2F8BFF;--text:#17181F;--text-muted:#5D6170;--success:#22A55B;--warn:#E8960F;--error:#E0443A;
 --hero-top:#FFFFFF;--hero-bottom:#F4F3F6;--violet:#7B6BFF;--pink:#EE5DB0;--green:#34C26A;--amber:#FFB020;--orange:#FF8A2B;
 --accent-rgb:58 91 255;--accent-dark-rgb:35 64 217;--sky-rgb:47 139 255;--skylight-rgb:140 204 255;--violet-rgb:123 107 255;--pink-rgb:238 93 176;--rose-rgb:255 182 214;--green-rgb:52 194 106;--lemon-rgb:226 238 96;--amber-rgb:255 176 32;--honey-rgb:255 214 122;--orange-rgb:255 138 43;--success-rgb:34 165 91;--white-rgb:255 255 255;--text-rgb:23 24 31;
 --flag-white:#FFFFFF;--flag-jp-red:#BC002D;--flag-us-red:#B22234;--flag-us-blue:#3C3B6E;--flag-sg-red:#EF3340;--flag-hk-red:#DE2910;--flag-au-blue:#012169;--flag-au-red:#E4002B;--flag-nl-red:#AE1C28;--flag-nl-blue:#21468B;
 --font-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Apple SD Gothic Neo","Malgun Gothic","Microsoft YaHei",system-ui,sans-serif;
 --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Apple SD Gothic Neo","Malgun Gothic","Microsoft YaHei",system-ui,sans-serif;
 --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
 --r-tile:36px;--r-tile-sm:26px;--r-card:24px;--r-brick:28px;--r-glass:18px;--r-chip:8px;--r-stage:40px;--r-pill:999px;--r-focus:10px;--r-small:12px;
 --shadow-panel:0 24px 64px rgb(var(--accent-rgb)/.10),0 2px 8px rgb(var(--accent-rgb)/.06);
 --shadow-float:0 14px 32px rgb(var(--accent-rgb)/.12),0 2px 6px rgb(var(--accent-rgb)/.06);
 --hl-inset:inset 0 1px 0 rgb(var(--white-rgb)/1),inset 0 0 0 1px rgb(var(--white-rgb)/.75);
 --gutter:24px;--content-width:1180px;--header-height:72px;--anchor-offset:92px;--toc-offset:152px;
 --size-body:16px;--size-small:14px;--size-h1:clamp(52px,5vw,72px);--size-h2:clamp(28px,3vw,40px);--size-h3:22px;
 --weight-display:800;--weight-bold:700;--weight-medium:500;--tracking-display:-.02em;--ease:ease;--speed:.2s;
 --veil:rgb(var(--text-rgb)/.22);--clear:transparent;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:var(--anchor-offset)}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--size-body);line-height:1.6;-webkit-font-smoothing:antialiased}
[hidden]{display:none!important}
img{display:block;max-width:100%;height:auto}
svg{flex-shrink:0}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
a{color:var(--accent);text-underline-offset:4px}
button,a,summary{touch-action:manipulation}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:var(--r-focus)}
h1,h2,h3{font-family:var(--font-display);color:var(--text);text-wrap:balance;line-height:1.2;letter-spacing:var(--tracking-display);overflow-wrap:break-word}
h1{font-size:var(--size-h1);font-weight:var(--weight-display);line-height:1.1;margin:0 0 24px}
h2{font-size:var(--size-h2);font-weight:var(--weight-display);margin:0 0 24px}
h3{font-size:var(--size-h3);font-weight:var(--weight-bold);margin:0 0 16px}
p{margin:0 0 20px}
ul,ol{padding-inline-start:24px}
code{font-family:var(--font-mono);overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:24px;background:var(--bg-panel-2);border-radius:var(--r-small)}
pre code{overflow-wrap:normal;white-space:pre}
section[id]{scroll-margin-top:var(--anchor-offset)}
body:has(.toc-tabs) section[id]{scroll-margin-top:var(--toc-offset)}
.no-break{white-space:nowrap}
.wrap{width:100%;max-width:var(--content-width);margin-inline:auto;padding-inline:var(--gutter)}
.sec{padding-top:80px;padding-bottom:80px}
.reading-wrap,.prose{max-width:800px;margin-inline:auto;min-width:0}
.prose{line-height:1.85}
.prose h2{margin-top:56px}
.prose h3{margin-top:32px}
.prose img{border-radius:var(--r-card)}
.muted{color:var(--text-muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.accent{color:var(--accent)}
.panel,.card{background:var(--bg-panel);border-radius:var(--r-card);padding:32px;box-shadow:var(--shadow-panel),var(--hl-inset);min-width:0}
.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.grid>*{min-width:0}
.stack{display:grid;gap:24px;min-width:0}
.row{display:flex;flex-wrap:wrap;align-items:center;gap:16px}
.section-intro{max-width:680px;margin-bottom:40px}
.section-intro p{color:var(--text-muted)}
.decorated{position:relative;overflow-x:clip;max-width:100%}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;height:54px;padding:0 32px;border:0;border-radius:var(--r-pill);font-size:17px;font-weight:var(--weight-bold);line-height:1;text-decoration:none;white-space:nowrap;flex-shrink:0;max-width:100%;transition:transform var(--speed),box-shadow var(--speed),background var(--speed)}
.btn svg{width:18px;height:18px}
.btn--primary,.btn-primary{color:var(--bg-panel);background:var(--accent);box-shadow:0 16px 32px -12px rgb(var(--accent-rgb)/.6),inset 0 1px 0 rgb(var(--white-rgb)/.28)}
.btn--primary:hover,.btn-primary:hover{background:var(--accent-dark);transform:translateY(-2px)}
.btn--ghost,.btn-secondary{color:var(--accent);background:var(--bg-panel-2)}
.btn--ghost:hover,.btn-secondary:hover{background:color-mix(in srgb,var(--bg-panel-2) 88%,var(--accent));transform:translateY(-2px)}
.btn:active{transform:translateY(0)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--bg-panel-2);color:var(--text-muted);box-shadow:none;cursor:not-allowed;transform:none}
.btn--small{height:44px;padding-inline:22px;font-size:var(--size-small)}
#site-header{position:sticky;top:0;z-index:60}
.topbar{position:relative;z-index:63;background:rgb(var(--white-rgb)/.8);backdrop-filter:blur(16px) saturate(1.4);box-shadow:0 1px 0 rgb(var(--text-rgb)/.05)}
.topbar__inner{max-width:1400px;height:var(--header-height);margin:0 auto;padding:0 40px;display:flex;align-items:center;gap:32px;flex-wrap:nowrap}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;flex:none;color:var(--text)}
.brand__mark{display:block;width:30px;height:30px}
.brand__word{font-family:var(--font-display);font-weight:var(--weight-display);font-size:20px;letter-spacing:-.02em}
.brand__zh{font-size:15px;font-weight:var(--weight-medium);color:var(--text-muted)}
.mainnav{margin:0 auto;flex:1;min-width:0}
.mainnav ul{display:flex;align-items:center;justify-content:center;list-style:none;margin:0;padding:0;gap:clamp(10px,1.6vw,28px)}
.mainnav a{display:block;padding:6px 2px;font-size:15px;font-weight:var(--weight-medium);color:var(--text-muted);text-decoration:none;white-space:nowrap;transition:color var(--speed)}
.mainnav a:hover,.mainnav a[aria-current="page"]{color:var(--text)}
.mainnav a[aria-current="page"]{font-weight:var(--weight-bold)}
.topbar__tools{display:flex;align-items:center;gap:10px;flex-shrink:0}
.langbox{position:relative}
.langpick{display:inline-flex;align-items:center;justify-content:center;width:auto;min-width:44px;height:40px;padding:0 14px;border:0;border-radius:var(--r-pill);background:var(--clear);color:var(--text-muted);font-size:14px;font-weight:var(--weight-medium);white-space:nowrap}
.langpick:hover{background:var(--bg-panel-2);color:var(--text)}
.langpanel{position:absolute;z-index:70;right:0;top:calc(100% + 12px);width:184px;padding:8px;background:var(--bg-panel);border-radius:var(--r-glass);box-shadow:var(--shadow-panel)}
.langpanel a{display:flex;align-items:center;min-height:44px;padding:8px 14px;border-radius:var(--r-small);text-decoration:none;color:var(--text)}
.langpanel a:hover,.langpanel a[aria-current]{background:var(--bg-panel-2);color:var(--accent)}
.btn-login{display:inline-flex;align-items:center;justify-content:center;height:40px;padding:0 22px;border-radius:var(--r-pill);background:var(--accent);color:var(--bg-panel);font-size:15px;font-weight:var(--weight-bold);text-decoration:none;white-space:nowrap;box-shadow:0 8px 20px -6px rgb(var(--accent-rgb)/.5),inset 0 1px 0 rgb(var(--white-rgb)/.25)}
.btn-login:hover{background:var(--accent-dark)}
.nav-toggle{display:none;align-items:center;justify-content:center;flex-direction:column;gap:5px;min-width:44px;min-height:44px;padding:10px;border:0;border-radius:var(--r-small);color:var(--text);background:var(--bg-panel-2)}
.nav-toggle__line{display:block;width:20px;height:2px;background:currentColor}
.nav-drawer{position:fixed;z-index:62;top:var(--header-height);left:0;right:0;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;padding:16px var(--gutter) 40px;background:var(--bg-panel)}
.nav-drawer ul{list-style:none;margin:0;padding:0}
.nav-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:12px 16px;color:var(--text);text-decoration:none;border-radius:var(--r-small)}
.nav-drawer a:hover,.nav-drawer a[aria-current]{background:var(--bg-panel-2);color:var(--accent)}
.drawer-languages{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));margin-top:16px;padding-top:16px;border-top:1px solid var(--border)}
.nav-veil{position:fixed;z-index:61;inset:var(--header-height) 0 0;border:0;background:var(--veil)}
html.nav-open{overflow:hidden}
.site-footer{background:var(--bg-panel-2);padding-top:64px;padding-bottom:32px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:48px}
.footer-grid>*{min-width:0}
.footer-brand p{max-width:330px;color:var(--text-muted);margin-top:20px}
.footer-title{font-size:16px;margin:0 0 16px;font-weight:var(--weight-bold)}
.footer-links{display:flex;flex-wrap:wrap;gap:4px 18px;list-style:none;margin:0;padding:0}
.footer-links li{min-width:0}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:32px;color:var(--text-muted);text-decoration:none}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{color:var(--accent)}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 24px;margin-top:40px}
.footer-legal{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:16px;margin-top:24px;padding-top:24px;border-top:1px solid var(--border);font-size:14px;color:var(--text-muted)}
.footer-legal p{margin:0}
.footer-legal div{display:flex;gap:20px}
.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:80px;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status+*{margin-top:24px}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.sr-only{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
@media(min-width:1101px){.nav-drawer,.nav-veil{display:none!important}}
@media(max-width:1280px){.topbar__inner{gap:20px;padding-inline:24px}.mainnav a{font-size:14px}.topbar__tools{gap:6px}.langpick{padding-inline:10px}}
@media(max-width:1100px){.mainnav{display:none}.topbar__tools{margin-left:auto}.nav-toggle{display:inline-flex}}
@media(max-width:768px){:root{--size-h1:clamp(28px,7vw,40px);--size-h2:30px;--gutter:20px}.grid{grid-template-columns:1fr}.sec{padding-top:56px;padding-bottom:56px}.footer-grid{grid-template-columns:1fr 1fr;gap:32px}.footer-brand{grid-column:1/-1}.panel,.card{padding:24px}}
@media(max-width:640px){:root{--gutter:16px}.no-break{white-space:normal}.tilt,.content-tilt{transform:none}.decorated{max-width:100%;overflow-x:clip}.topbar__inner{padding-inline:16px;gap:8px}.topbar__tools{margin-left:auto;gap:4px}.brand{gap:6px}.brand__mark{width:26px;height:26px}.brand__word{font-size:18px}.langpick{padding-inline:8px;font-size:12px}.btn-login{padding-inline:14px;font-size:14px}.brand__zh{font-size:12px}.btn{padding-inline:24px}.footer-grid{grid-template-columns:1fr}.footer-legal{align-items:flex-start;flex-direction:column}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{animation:none!important;transition:none!important}.reveal,.reveal.pending{opacity:1;transform:none}}