:root{
--bg:#E7EFFA;--bg-panel:#F7FAFE;--bg-panel-2:#D9E5F4;--border:#C9D7EA;--border-soft:#E1E9F4;
--accent:#0F74E8;--accent-dark:#0A53B8;--accent-soft:#3D93F3;--accent-tint:#E5F0FD;--accent-tint-2:#CFE2FB;--accent-tint-0:rgba(229,240,253,0);
--text:#0F1B33;--ink:#0F1B33;--text-muted:#55637D;--text-sky:#1B3055;--text-on-ink:#E8EEF8;--text-on-ink-muted:#9FB0CC;
--success:#16A35A;--success-tint:#DDF3E6;--warn:#E8890C;--warn-tint:#FCEBD1;--error:#D93A3A;
--violet:#7B5CF0;--violet-tint:#ECE7FE;--slate:#5A6A85;--slate-tint:#E4EAF3;--white:#FFFFFF;
--sky-1:#A9D6F8;--sky-2:#74B7F0;--sky-3:#5AA3EA;--sky-glow:rgba(255,255,255,.5);
--hill-1:#C4E4FB;--hill-2:#9CCDF4;--hill-3:#6DB4EC;--hill-4:#4296E0;--hill-cyan:#93D5EF;
--note:#FFF6D8;--note-edge:#F0DC9E;--flag-red:#D93A3A;--flag-gold:#F2C230;--flag-navy:#1D3F8F;--flag-white:#FFFFFF;--flag-black:#0F1B33;--flag-edge:rgba(15,27,51,.16);
--veil-90:rgba(255,255,255,.9);--veil-72:rgba(255,255,255,.72);--veil-55:rgba(255,255,255,.55);--veil-35:rgba(255,255,255,.35);--veil-20:rgba(255,255,255,.2);--veil-12:rgba(255,255,255,.12);
--glass-ink:rgba(15,27,51,.86);--shadow-blue:rgba(15,116,232,.12);--shadow-blue-strong:rgba(15,116,232,.14);--shadow-blue-cta:rgba(15,116,232,.32);--shadow-ink:rgba(15,27,51,.22);--grid-ink:rgba(15,27,51,.06);--clear:transparent;
--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","Microsoft YaHei",system-ui,-apple-system,"Segoe UI",sans-serif;
--font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
--weight-normal:400;--weight-medium:500;--weight-semibold:600;--weight-bold:700;--weight-heavy:800;--weight-display:900;
--f-tiny:10.5px;--f-mini:11px;--f-meta:11.5px;--f-xs:12px;--f-small:12.5px;--f-sm:13px;--f-label:13.5px;--f-ui:14px;--f-login:14.5px;--f-nav:15px;--f-body:16px;--f-cta:17px;--f-lead:18px;--f-sub:20px;--f-brand:21px;--f-h3:24px;--f-h2:clamp(28px,3vw,40px);--f-h1:clamp(52px,5vw,68px);--f-hero:64px;--f-mobile-h1:clamp(28px,7.8vw,40px);
--r-card:40px;--r-frame:30px;--r-window:24px;--r-lg:18px;--r-md:14px;--r-plan:12px;--r-sm:9px;--r-focus:8px;--r-badge:7px;--r-icon:5px;--r-flag:3px;--r-pill:999px;--r-circle:50%;
--gutter:clamp(16px,4.2vw,60px);--shell:min(1240px,calc(100vw - 120px));--content-max:1360px;--reading-max:800px;
--header-height:60px;--anchor-offset:80px;--toc-offset:96px;--ease: cubic-bezier(.2,.65,.3,1);--fast:180ms;--reveal-time:600ms;
--shadow-panel:0 24px 48px var(--shadow-blue-strong);--shadow-card:0 16px 40px var(--shadow-blue);
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-offset);scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--f-body);line-height:1.5;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{background:none;border:0;padding:0;cursor:pointer}
img{display:block;max-width:100%;height:auto}
svg{display:block;flex-shrink:0}
ul{list-style:none;margin:0;padding:0}
p,h1,h2,h3,h4,figure,blockquote{margin:0}
h1,h2,h3{font-family:var(--font-display);font-weight:var(--weight-display);text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--f-h1);line-height:1.1;letter-spacing:-.02em}
h2{font-size:var(--f-h2);line-height:1.2;letter-spacing:-.02em}
h3{font-size:var(--f-h3);line-height:1.3}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:var(--r-focus)}
[hidden]{display:none!important}
.no-break{white-space:nowrap}
.wrap{width:100%;max-width:var(--content-max);margin-inline:auto;padding-inline:var(--gutter)}
.sec{padding-top:64px;padding-bottom:64px}
.reading-wrap{max-width:var(--reading-max);margin-inline:auto;padding-inline:var(--gutter)}
.prose{line-height:1.85;overflow-wrap:break-word;min-width:0}
.prose p,.prose ul,.prose ol,.prose pre,.prose table,.prose blockquote{margin-block:20px}
.prose ul{list-style:disc;padding-left:24px}
.prose ol{padding-left:24px}
.prose h2{margin-top:48px;margin-bottom:20px}
.prose h3{margin-top:32px;margin-bottom:16px}
.prose a,.text-link{color:var(--accent-dark);text-decoration:underline;text-underline-offset:4px}
code{font-family:var(--font-mono);font-size:.9em;overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;background:var(--bg-panel-2);padding:20px;border-radius:var(--r-md)}
pre code{white-space:pre;overflow-wrap:normal}
.grid{display:grid;gap:24px;grid-template-columns:repeat(3,minmax(0,1fr))}
.grid>*{min-width:0}
.panel,.card{min-width:0;padding:28px;background:var(--bg-panel);border:1px solid var(--border-soft);border-radius:var(--r-window);box-shadow:var(--shadow-card),inset 0 1px 0 var(--white)}
.muted{color:var(--text-muted)}
.section-head{margin-bottom:32px}
.section-head p{margin-top:12px;color:var(--text-muted)}
.reveal{transition:opacity var(--reveal-time) var(--ease),transform var(--reveal-time) var(--ease)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-height:120px;max-width:100%;overflow:hidden;margin-block:24px}
#server-status+*{margin-top:32px}
.decor-section{position:relative;overflow-x:clip}
.btn,.btn-primary,.btn-ghost,.btn-secondary,.login{display:inline-flex;align-items:center;justify-content:center;flex-shrink:0;white-space:nowrap;min-height:44px;border-radius:var(--r-pill);font-weight:var(--weight-bold)}
.btn,.btn-secondary{padding:12px 24px;background:var(--accent);color:var(--white);box-shadow:inset 0 1px 0 var(--veil-35)}
.btn:hover,.btn-secondary:hover{background:var(--accent-dark)}
.btn:active,.btn-primary:active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--bg-panel-2);color:var(--text-muted);cursor:not-allowed;box-shadow:none}
.btn-primary{gap:16px;height:52px;padding:0 8px 0 30px;background:linear-gradient(180deg,var(--accent-soft),var(--accent) 60%,var(--accent-dark) 140%);color:var(--white);font-size:var(--f-cta);font-weight:var(--weight-heavy);letter-spacing:.01em;box-shadow:inset 0 1px 0 var(--veil-35),0 0 0 8px var(--veil-90),0 0 0 9px var(--shadow-blue),0 22px 40px var(--shadow-blue-cta);transition:transform var(--fast) var(--ease)}
.prose a.btn,.prose a.btn-primary,.prose a.btn-secondary{color:var(--white);text-decoration:none}
.btn-primary:hover{transform:translateY(-1px)}
.btn-arrow{width:36px;height:36px;border-radius:var(--r-circle);display:grid;place-items:center;background:var(--veil-20);box-shadow:inset 0 0 0 1px var(--veil-35)}
.btn-arrow svg{width:17px;height:17px}
.btn-ghost{height:52px;padding:0 28px;background:var(--white);border:1px solid var(--border);font-size:var(--f-body);box-shadow:0 8px 20px var(--shadow-blue)}
.btn-ghost:hover{border-color:var(--accent)}
.ann{background:var(--ink);height:34px;display:flex;align-items:center;justify-content:center}
.ann-link{display:inline-flex;align-items:center;gap:12px;height:100%;font-size:var(--f-label);font-weight:var(--weight-medium);color:var(--text-on-ink)}
.ann-new{display:inline-flex;align-items:center;height:22px;padding:0 9px;border-radius:var(--r-badge);background:linear-gradient(180deg,var(--accent-soft),var(--accent));box-shadow:inset 0 0 0 1px var(--veil-35);font-size:var(--f-mini);font-weight:var(--weight-heavy);letter-spacing:.06em;color:var(--white)}
.ann-main{font-weight:var(--weight-bold);color:var(--white)}
.ann-sub{color:var(--text-on-ink-muted)}
.ann-arrow{width:14px;height:14px;color:var(--text-on-ink-muted)}
.topbar{position:relative;z-index:20;height:var(--header-height);background:var(--bg-panel);border-bottom:1px solid var(--border-soft)}
.topbar-in{width:min(1300px,calc(100% - 80px));height:100%;margin:auto;display:flex;align-items:center;gap:40px}
.brand{display:inline-flex;align-items:center;gap:10px;min-height:30px;flex-shrink:0}
.brand .logo{width:30px;height:30px}
.brand-word{font-family:var(--font-display);font-weight:var(--weight-display);font-size:var(--f-brand);letter-spacing:-.02em}
.brand-zh{font-size:var(--f-ui);font-weight:var(--weight-medium);color:var(--text-muted)}
.mainnav,.mainnav>ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:4px}
.mainnav>ul>li>a,.more-btn{position:relative;display:inline-flex;align-items:center;justify-content:center;gap:6px;height:38px;padding:0 13px;border-radius:var(--r-pill);font-size:var(--f-nav);font-weight:var(--weight-medium)}
.mainnav a:hover,.more-btn:hover{background:var(--bg-panel-2)}
.mainnav a.is-active{font-weight:var(--weight-heavy)}
.mainnav>ul>li>a.is-active::after{content:"";position:absolute;left:50%;bottom:3px;width:16px;height:3px;margin-left:-8px;border-radius:var(--r-flag);background:var(--accent)}
.more{position:relative}
.more-btn svg{width:12px;height:12px;color:var(--text-muted)}
.more-menu{position:absolute;top:calc(100% + 10px);left:-10px;width:420px;padding:12px;display:grid;grid-template-columns:1fr 1fr;gap:6px 10px;border-radius:var(--r-lg);background:var(--white);border:1px solid var(--border-soft);box-shadow:var(--shadow-panel)}
.menu-group{display:flex;flex-direction:column;gap:2px;min-width:0}
.menu-label{padding:4px 10px 6px;font-size:var(--f-meta);font-weight:var(--weight-bold);color:var(--text-muted)}
.menu-item{display:flex;align-items:center;gap:10px;padding:8px 10px;min-height:44px;border-radius:var(--r-md)}
.menu-item:hover{background:var(--bg-panel)}
.menu-ico{width:30px;height:30px;border-radius:var(--r-sm);display:grid;place-items:center;flex-shrink:0}
.menu-ico svg{width:16px;height:16px}
.menu-txt{display:flex;flex-direction:column;line-height:1.3}
.menu-txt b{font-size:var(--f-ui);font-weight:var(--weight-bold)}
.menu-txt span{font-size:var(--f-xs);color:var(--text-muted)}
.tone-blue{background:var(--accent-tint);color:var(--accent)}
.tone-violet{background:var(--violet-tint);color:var(--violet)}
.tone-green{background:var(--success-tint);color:var(--success)}
.tone-orange{background:var(--warn-tint);color:var(--warn)}
.tone-slate{background:var(--slate-tint);color:var(--slate)}
.topbar-tools{margin-left:auto;display:flex;align-items:center;gap:10px}
.lang-box{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-width:44px;width:auto;height:38px;padding:0 14px;border-radius:var(--r-pill);border:1px solid var(--border-soft);background:var(--white);font-size:var(--f-ui);font-weight:var(--weight-semibold)}
.lang span{white-space:nowrap}
.lang svg{width:15px;height:15px;color:var(--text-muted)}
.lang .chev{width:11px;height:11px}
.lang-menu{position:absolute;right:0;top:48px;min-width:180px;padding:8px;border:1px solid var(--border);border-radius:var(--r-md);background:var(--white);box-shadow:var(--shadow-panel)}
.lang-menu a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-sm)}
.lang-menu a:hover,.lang-menu a[aria-current]{background:var(--accent-tint);color:var(--accent-dark)}
.login{height:38px;min-height:38px;padding:0 22px;background:var(--ink);color:var(--white);font-size:var(--f-login);font-weight:var(--weight-heavy);box-shadow:0 8px 18px var(--shadow-ink)}
.hamburger{display:none;min-width:44px;min-height:44px;border-radius:var(--r-sm);background:var(--bg-panel-2)}
.hamburger svg{width:22px;height:22px}
.mobile-drawer{display:none}
.nav-veil{position:fixed;inset:94px 0 0;z-index:10;background:var(--shadow-ink)}
html.nav-open{overflow:hidden}
.site-footer{background:var(--bg-panel);border-top:1px solid var(--border);padding-top:56px;padding-bottom:32px}
.footer-grid{display:grid;grid-template-columns:1.25fr 1fr 1fr;gap:48px}
.footer-grid>*{min-width:0}
.footer-brand p{margin-top:20px;max-width:340px;color:var(--text-muted)}
.footer-title{font-size:var(--f-ui);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,.legal-links a{display:inline-flex;align-items:center;min-height:28px;font-size:var(--f-ui)}
.footer-links a:hover,.legal-links a:hover{color:var(--accent-dark)}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 20px;margin-top:32px}
.footer-bottom{display:flex;flex-wrap:wrap;justify-content:space-between;gap:16px;margin-top:24px;padding-top:24px;border-top:1px solid var(--border);font-size:var(--f-sm);color:var(--text-muted)}
.legal-links{display:flex;flex-wrap:wrap;gap:20px}
@media(max-width:1100px){
.topbar-in{width:calc(100% - 40px);gap:20px}
.mainnav>ul>li>a,.more-btn{padding-inline:9px;font-size:var(--f-ui)}
}
@media(max-width:900px){
.mainnav{display:none}
.topbar-in{width:100%;padding-inline:16px;gap:12px}
.topbar-tools{margin-left:auto;gap:8px}
.hamburger{display:grid;place-items:center}
.mobile-drawer:not([hidden]){display:block;position:absolute;left:0;right:0;top:100%;z-index:22;background:var(--bg-panel);padding:16px;max-height:calc(100dvh - 94px);overflow-y:auto;overscroll-behavior:contain;border-bottom:1px solid var(--border);box-shadow:var(--shadow-panel)}
.mobile-drawer a{display:flex;width:100%;align-items:center;min-height:44px;padding:12px 16px;border-radius:var(--r-sm)}
.mobile-drawer a:hover,.mobile-drawer a.is-active{background:var(--accent-tint);color:var(--accent-dark)}
.mobile-drawer .menu-label{margin-top:12px}
.footer-grid{grid-template-columns:1fr 1fr}
.footer-brand{grid-column:1/-1}
}
@media(max-width:768px){
h1{font-size:var(--f-mobile-h1)}
.grid{grid-template-columns:1fr}
.sec{padding-top:40px;padding-bottom:40px}
}
@media(max-width:640px){
.no-break{white-space:normal}
.wrap,.reading-wrap{padding-inline:var(--gutter);max-width:100%}
.tilt,.decor-tilt{transform:none!important}
.decor-section{max-width:100%;overflow-x:clip}
.lang{padding-inline:10px}
.lang .lang-label{display:none}
.login{padding-inline:16px}
.brand{gap:6px}
.brand-word{font-size:var(--f-lead)}
.brand .logo{width:26px;height:26px}
.ann-sub{display:none}
.footer-grid{grid-template-columns:1fr;gap:28px}
.footer-brand{grid-column:auto}
.panel,.card{padding:20px}
}
@media(prefers-reduced-motion:reduce){
html{scroll-behavior:auto}
*,*::before,*::after{transition-duration:0s!important}
.reveal,.reveal.pending{opacity:1;transform:none}
}