:root{
  --bg:#E4EEF5;--bg-top:#F2F7FB;--bg-bottom:#DCE8F1;
  --panel:#F7FAFD;--groove:#D7E5EF;--border:#C6D6E3;--line-soft:#E4ECF3;
  --white:#FFFFFF;--chip:rgba(255,255,255,.72);--transparent:transparent;
  --accent:#E8563A;--accent-dark:#C13E24;--accent-glow:#F07A4F;--accent-tint:#FCE4DC;--accent-tint-2:#F9C6B6;
  --text:#142235;--ink-2:#2A3B50;--muted:#566A80;--faint:#8396AA;
  --blue:#2F7BDB;--blue-ink:#1F5FB0;--blue-soft:#DDEAFB;--cyan:#22A9C9;
  --green:#1FA971;--green-ink:#137A52;--green-soft:#D6F1E5;
  --yellow:#F2B233;--yellow-ink:#8A5D05;--yellow-soft:#FCEFD0;
  --pink:#E86A9A;--pink-ink:#B03D6B;--pink-soft:#FBE1EB;--error:#D93B48;
  --flag-red:#D52B3A;--flag-white:#FFFFFF;--flag-navy:#24397F;--flag-edge:rgba(20,34,53,.12);
  --plate-a:#EEF5FA;--plate-b:#D3E3EE;
  --hl:rgba(255,255,255,.9);--hl-soft:rgba(255,255,255,.35);--glow-white:rgba(255,255,255,.75);
  --sh-blue-06:rgba(47,123,219,.06);--sh-blue-08:rgba(47,123,219,.08);--sh-blue-10:rgba(47,123,219,.10);
  --sh-blue-12:rgba(47,123,219,.12);--sh-blue-18:rgba(47,123,219,.18);--sh-blue-24:rgba(47,123,219,.24);
  --sh-navy-20:rgba(20,34,53,.20);--sh-navy-30:rgba(20,34,53,.30);--sh-navy-40:rgba(20,34,53,.40);
  --sh-coral:rgba(232,86,58,.42);--hover-tint:rgba(47,123,219,.07);
  --r-plate:28px;--r-window:20px;--r-card:16px;--r-small:10px;--r-block:8px;--r-flag:3px;--r-pill:999px;--r-round:50%;--r-keyword:.2em;
  --font-display:"Inter","Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --size-body:17px;--size-small:14px;--size-h1:clamp(52px,4.45vw,64px);--size-h2:44px;--size-h3:28px;
  --weight-display:800;--weight-bold:700;--weight-medium:600;
  --tracking-display:-.03em;--leading-body:1.65;--leading-display:1.1;
  --gutter:32px;--content-max:1376px;--reading-max:800px;--header-height:72px;--toc-offset:88px;--anchor-offset:164px;
  --space-1:8px;--space-2:16px;--space-3:24px;--space-4:32px;--space-5:40px;--space-6:48px;--space-8:64px;--space-12:96px;
  --contour-alpha:.035;--ease:ease;--duration:.2s;
  --shadow-panel:0 24px 56px -24px var(--sh-blue-18),inset 0 1px 0 var(--hl);
  --contour-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1440 900' preserveAspectRatio='xMidYMid slice'%3E%3Cdefs%3E%3Cpath id='c' vector-effect='non-scaling-stroke' d='M0-80C62-84 132-58 130-6 128 44 70 86 2 84-62 82-134 50-132 2-130-46-60-76 0-80Z'/%3E%3C/defs%3E%3Cg fill='none' stroke='currentColor' stroke-width='1.5'%3E%3Cg transform='translate(1060 500)'%3E%3Cuse href='%23c' transform='scale(.7)'/%3E%3Cuse href='%23c' transform='scale(1.3)'/%3E%3Cuse href='%23c' transform='scale(1.9)'/%3E%3Cuse href='%23c' transform='scale(2.5)'/%3E%3Cuse href='%23c' transform='scale(3.1)'/%3E%3Cuse href='%23c' transform='scale(3.7)'/%3E%3Cuse href='%23c' transform='scale(4.3)'/%3E%3C/g%3E%3Cg transform='translate(220 150) rotate(24)'%3E%3Cuse href='%23c' transform='scale(.6)'/%3E%3Cuse href='%23c' transform='scale(1.2)'/%3E%3Cuse href='%23c' transform='scale(1.8)'/%3E%3Cuse href='%23c' transform='scale(2.4)'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--toc-offset);scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--size-body);line-height:var(--leading-body);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
img{display:block;max-width:100%;height:auto}
svg{flex-shrink:0}
button,a,summary,input,select,textarea,[tabindex]{-webkit-tap-highlight-color:var(--hover-tint)}
:where(a,button,summary,input,select,textarea,[tabindex]):focus-visible{outline:2px solid var(--blue);outline-offset:3px}
button:disabled,[aria-disabled="true"]{cursor:not-allowed;opacity:.55}
[hidden]{display:none!important}
h1,h2,h3,h4,p,ul,ol,figure,blockquote{margin-top:0}
h1,h2,h3,h4{font-family:var(--font-display);text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--size-h1);line-height:var(--leading-display);letter-spacing:var(--tracking-display);font-weight:var(--weight-display)}
h2{font-size:var(--size-h2);line-height:1.15;letter-spacing:var(--tracking-display);font-weight:var(--weight-display)}
h3{font-size:var(--size-h3);line-height:1.3;letter-spacing:-.02em}
:lang(zh-CN) h1,:lang(zh-CN) h2,:lang(zh-TW) h1,:lang(zh-TW) h2,:lang(ja) h1,:lang(ko) h1{letter-spacing:-.02em}
p{margin-bottom:var(--space-3)}
code{font-family:var(--font-mono);overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:var(--space-3);background:var(--groove);border-radius:var(--r-card)}
pre code{overflow-wrap:normal;white-space:pre}
hr{border:0;border-top:1px solid var(--border);margin-block:var(--space-4)}
main,section,article,aside,nav,figure,div{min-width:0}
.wrap{width:100%;max-width:var(--content-max);padding-inline:var(--gutter);margin-inline:auto}
.section{padding-top:var(--space-12);padding-bottom:var(--space-12)}
.reading{max-width:var(--reading-max);margin-inline:auto}
.prose{overflow-wrap:break-word}
.prose a{color:var(--blue-ink);text-decoration:underline;text-underline-offset:3px}
.prose h2,.prose h3{margin-top:var(--space-6)}
.prose li+li{margin-top:var(--space-1)}
.no-break{white-space:nowrap}
.sr-only{position:absolute;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}
.muted{color:var(--muted)}
.accent-text{color:var(--accent-dark)}
.mono{font-family:var(--font-mono)}
.section-title{text-align:center;margin-bottom:var(--space-4)}
.panel,.card{background:var(--panel);border:1px solid var(--border);border-radius:var(--r-card);padding:var(--space-4);box-shadow:var(--shadow-panel)}
.panel--groove{background:var(--groove)}
.grid-three{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:var(--space-3)}
.stack{display:grid;gap:var(--space-3)}
.cta{display:flex;flex-wrap:wrap;gap:12px;margin-bottom:32px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:56px;padding:12px 28px;border:0;border-radius:var(--r-pill);font-size:var(--size-body);font-weight:var(--weight-bold);letter-spacing:-.005em;line-height:1.4;white-space:nowrap;flex-shrink:0;transition:background-color var(--duration) var(--ease),box-shadow var(--duration) var(--ease),transform var(--duration) var(--ease)}
.btn svg{width:20px;height:20px}
.btn--main,.btn-primary{color:var(--white);background:linear-gradient(135deg,var(--accent-glow) 0%,var(--accent) 60%);box-shadow:0 16px 28px -14px var(--sh-coral),inset 0 1px 0 var(--hl-soft)}
.btn--main:hover,.btn-primary:hover{background:var(--accent-dark);transform:translateY(-1px)}
.btn--ghost,.btn-secondary{color:var(--text);background:var(--white);border:1px solid var(--border);box-shadow:0 6px 16px -10px var(--sh-blue-24)}
.btn--ghost:hover,.btn-secondary:hover{border-color:var(--text)}
.btn--small{min-height:44px;font-size:var(--size-small);padding:10px 20px}
.btn--text{background:var(--transparent);color:var(--blue-ink)}
.btn.is-hover{background:var(--accent-dark);color:var(--white)}
.btn.is-focus{outline:2px solid var(--blue);outline-offset:3px}
.stage{position:relative;overflow-x:clip;max-width:100%;background:linear-gradient(180deg,var(--bg-top) 0%,var(--bg-bottom) 100%)}
.stage::before{content:"";position:absolute;inset:0;pointer-events:none;background-color:var(--text);opacity:var(--contour-alpha);-webkit-mask-image:var(--contour-image);mask-image:var(--contour-image);-webkit-mask-size:cover;mask-size:cover;-webkit-mask-position:center;mask-position:center;-webkit-mask-repeat:no-repeat;mask-repeat:no-repeat}
.topbar{position:relative;z-index:60}
.topbar__inner{height:var(--header-height);display:flex;align-items:center;gap:24px;flex-wrap:nowrap}
.brand{display:inline-flex;align-items:center;gap:10px;font-family:var(--font-display);font-weight:var(--weight-display);font-size:20px;letter-spacing:-.02em;color:var(--text);flex-shrink:0;min-height:44px}
.brand img{width:32px;height:32px}
.brand__zh{font-weight:500;color:var(--muted)}
.mainnav{display:flex;align-items:center;gap:4px;margin-left:16px;flex:1;min-width:0}
.mainnav ul{display:flex;align-items:center;gap:4px;list-style:none;margin:0;padding:0}
.mainnav__link,.more__btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:40px;padding:0 16px;border:0;border-radius:var(--r-pill);background:var(--transparent);font-size:15px;font-weight:500;color:var(--ink-2);white-space:nowrap}
.mainnav__link:hover,.more__btn:hover{background:var(--hover-tint)}
.mainnav__link[aria-current="page"],.more__link[aria-current="page"],.more__btn.is-current{background:var(--accent-tint);color:var(--accent-dark);font-weight:600}
.more__btn svg{width:14px;height:14px}
.more{position:relative}
.more__menu{position:absolute;top:100%;left:0;padding-top:8px;display:none;z-index:65}
.more.is-open .more__menu,.more:hover .more__menu,.more:focus-within .more__menu{display:block}
.more__panel{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px 16px;width:360px;padding:16px;background:var(--white);border:1px solid var(--border);border-radius:var(--r-card);box-shadow:0 24px 48px -16px var(--sh-blue-24)}
.more__group{display:flex;flex-direction:column;gap:2px}
.more__label{font-size:12px;font-weight:600;color:var(--muted);padding:4px 10px 6px}
.more__link{display:flex;align-items:center;min-height:40px;padding:8px 10px;border-radius:var(--r-small);font-size:14px;color:var(--ink-2)}
.more__link:hover{background:var(--hover-tint)}
.topbar__end{margin-left:auto;display:flex;align-items:center;gap:12px;flex-shrink:0}
.language{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:40px;min-width:44px;width:auto;padding:0 14px;border:0;border-radius:var(--r-pill);background:var(--transparent);font-size:14px;color:var(--muted);white-space:nowrap}
.lang span{white-space:nowrap}
.lang:hover{background:var(--hover-tint)}
.lang svg{width:16px;height:16px}
.language__panel{display:none;position:absolute;top:calc(100% + 8px);right:0;z-index:80;min-width:176px;padding:8px;background:var(--white);border:1px solid var(--border);border-radius:var(--r-card);box-shadow:var(--shadow-panel)}
.language.is-open .language__panel{display:grid}
.language__link{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-small);font-size:14px;white-space:nowrap}
.language__link:hover,.language__link[aria-current="true"]{background:var(--groove)}
.login{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:40px;padding:0 20px;border:1.5px solid var(--text);border-radius:var(--r-pill);background:var(--white);font-size:15px;font-weight:600;color:var(--text);white-space:nowrap;transition:background-color var(--duration),color var(--duration)}
.login:hover{background:var(--text);color:var(--white)}
.login svg{width:16px;height:16px}
.burger{display:none;align-items:center;justify-content:center;flex-direction:column;gap:4px;min-width:44px;min-height:44px;padding:10px;border:1px solid var(--border);border-radius:var(--r-small);background:var(--panel);color:var(--text)}
.burger__line{display:block;width:20px;height:2px;background:currentColor}
.mobile-drawer{display:none}
.nav-veil{display:none}
html.nav-open{overflow:hidden}
.site-footer{position:relative;background:var(--panel);border-top:1px solid var(--border);padding-top:64px;padding-bottom:32px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:40px}
.footer-brand p{max-width:28em;margin-top:16px;font-size:14px;color:var(--muted)}
.footer-column h2{font-size:15px;letter-spacing:0;margin-bottom:16px}
.footer-links{display:grid;gap:4px;margin:0;padding:0;list-style:none}
.footer-links a{display:inline-flex;align-items:center;min-height:32px;font-size:14px;color:var(--muted)}
.footer-links a:hover{color:var(--blue-ink);text-decoration:underline}
.footer-bottom{display:flex;flex-wrap:wrap;align-items:center;gap:16px;margin-top:40px;padding-top:24px;border-top:1px solid var(--border);font-size:13px;color:var(--muted)}
.footer-legal{display:flex;flex-wrap:wrap;gap:16px;margin-left:auto}
.footer-legal a{display:inline-flex;align-items:center;min-height:28px}
.reveal{transition:opacity .35s var(--ease),transform .35s var(--ease)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
.counter-value,[data-counter]{display:inline-block;min-width:3ch;font-variant-numeric:tabular-nums;font-family:var(--font-mono)}
#server-status{position:relative;display:block;min-width:0;max-width:100%;overflow:hidden;margin-top:var(--space-4);margin-bottom:var(--space-4)}
#server-status+*{margin-top:var(--space-4)}
.fw{fill:var(--flag-white)}.fr{fill:var(--flag-red)}.fn{fill:var(--flag-navy)}
.fish-a{fill:var(--blue)}.fish-b{fill:var(--cyan)}
.wave{fill:none;stroke:var(--blue-soft);stroke-width:1.4;stroke-linecap:round}
@media(min-width:901px){.more:hover .more__btn{background:var(--hover-tint)}}
@media(max-width:1150px){
  .topbar__inner{gap:16px}.mainnav{margin-left:0}.mainnav__link,.more__btn{padding-inline:10px}.topbar__end{gap:8px}
}
@media(max-width:900px){
  .mainnav{display:none}.topbar__end{margin-left:auto}.burger{display:flex}
  .topbar{background:var(--bg-top)}
  .mobile-drawer{position:fixed;top:var(--header-height);left:0;right:0;z-index:55;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;background:var(--panel);padding:16px var(--gutter) 40px}
  .mobile-drawer.is-open{display:block}
  .mobile-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;border-radius:var(--r-small);font-size:16px}
  .mobile-drawer a:hover,.mobile-drawer a[aria-current="page"]{background:var(--accent-tint);color:var(--accent-dark)}
  .mobile-drawer__languages{display:grid;border-top:1px solid var(--border);margin-top:16px;padding-top:16px}
  .nav-veil{position:fixed;top:var(--header-height);inset-inline:0;bottom:0;z-index:50;background:var(--sh-navy-40);border:0}
  .nav-veil.is-open{display:block}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:768px){
  :root{--size-h1:38px;--size-h2:32px;--size-h3:24px;--gutter:24px}
  .section{padding-top:64px;padding-bottom:64px}
  .grid-three{grid-template-columns:1fr}
}
@media(max-width:640px){
  :root{--gutter:16px;--header-height:64px;--toc-offset:80px;--anchor-offset:148px}
  .no-break{white-space:normal}
  .tilt,[data-tilt]{transform:none}
  .stage,.decoration-zone{max-width:100%;overflow-x:clip}
  .topbar__inner{gap:8px}.brand{font-size:17px;gap:7px}.brand img{width:28px;height:28px}
  .topbar__end{gap:4px;margin-left:auto}.login{min-height:38px;padding-inline:12px;font-size:14px}.login svg{display:none}
  .lang{padding-inline:6px;font-size:12px;gap:3px}.lang svg{width:14px;height:14px}
  .panel,.card{padding:24px}
  .footer-grid{gap:24px;grid-template-columns:1fr 1fr}
  .footer-brand{grid-column:1/-1}
  .footer-bottom{align-items:flex-start;flex-direction:column}
  .footer-legal{margin-left:0}
}
@media(max-width:359px){
  .brand{font-size:15px}.brand img{width:24px;height:24px}.brand{gap:5px}
  .lang{font-size:11px}.lang svg{display:none}.login{padding-inline:9px}.burger{min-width:40px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms!important;transition-duration:.01ms!important}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none}
}