:root{
  --bg:#F9EFE0;
  --bg-panel:#FFFBF4;
  --bg-panel-2:#F1E5D2;
  --border:#E4D5BE;
  --accent:#4130E6;
  --accent-dark:#2A1DB0;
  --text:#2A2119;
  --text-muted:#6E6152;
  --success:#1F8A5B;
  --warn:#C9831A;
  --error:#C8362E;
  --coral:#FF7B5C;
  --hero-top:#FCF6EC;
  --hero-bottom:#F3E6D2;
  --page:#FFFFFF;
  --ink:#1E1812;
  --on-accent:var(--bg-panel);
  --tl-red:#EE6A5F;
  --tl-yellow:#F3BE4F;
  --tl-green:#5DBE6A;
  --flag-red:#D52B1E;
  --flag-white:#FFFFFF;
  --flag-navy:#2B3A7C;
  --mask-ink:#000000;
  --clear:transparent;
  --chrome:color-mix(in srgb,var(--bg-panel-2) 42%,var(--bg-panel));
  --border-soft:color-mix(in srgb,var(--border) 72%,transparent);
  --border-strong:color-mix(in srgb,var(--border) 64%,var(--text-muted));
  --flag-edge:color-mix(in srgb,var(--text) 14%,transparent);
  --accent-tint:color-mix(in srgb,var(--accent) 24%,var(--page));
  --accent-wash:color-mix(in srgb,var(--accent) 6%,var(--bg-panel));
  --coral-soft:color-mix(in srgb,var(--coral) 84%,var(--page));
  --coral-rim:color-mix(in srgb,var(--coral) 86%,var(--text));
  --kw-block:color-mix(in srgb,var(--coral) 30%,transparent);
  --glow-apricot:color-mix(in srgb,var(--coral) 24%,transparent);
  --glow-blue:color-mix(in srgb,var(--accent) 15%,transparent);
  --hi-line:color-mix(in srgb,var(--page) 58%,transparent);
  --shadow-tint:color-mix(in srgb,var(--accent) 10%,transparent);
  --shadow-tint-strong:color-mix(in srgb,var(--accent) 16%,transparent);
  --shadow-cta:color-mix(in srgb,var(--accent) 30%,transparent);
  --shadow-warm:color-mix(in srgb,var(--text) 12%,transparent);
  --orb-a:color-mix(in srgb,var(--accent) 9%,var(--page));
  --orb-b:color-mix(in srgb,var(--accent) 22%,var(--page));
  --veil:color-mix(in srgb,var(--ink) 35%,transparent);
  --success-wash:color-mix(in srgb,var(--success) 10%,var(--bg-panel));
  --warn-wash:color-mix(in srgb,var(--warn) 10%,var(--bg-panel));
  --error-wash:color-mix(in srgb,var(--error) 8%,var(--bg-panel));
  --radius-win:14px;
  --radius-card:10px;
  --radius-sm:8px;
  --radius-tile:12px;
  --radius-inner:5px;
  --radius-dot:50%;
  --radius-pill:999px;
  --font-display:Georgia,'Times New Roman','Songti SC','Noto Serif SC','STSong','Hiragino Mincho ProN','Nanum Myeongjo',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;
  --gutter:40px;
  --content-width:1280px;
  --reading-width:820px;
  --header-height:64px;
  --anchor-offset:88px;
  --toc-offset:148px;
  --section-space:88px;
  --ease-out:cubic-bezier(.2,.7,.2,1);
  --reveal-time:.35s;
  --grain-paper:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='g'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='3' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 .2 0 0 0 0 .13 0 0 0 0 .07 .3 0 0 0 -.12'/%3E%3C/filter%3E%3Crect width='180' height='180' filter='url(%23g)'/%3E%3C/svg%3E");
  --grain-light:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='g'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='3' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 1.1 0 0 0 -.48'/%3E%3C/filter%3E%3Crect width='180' height='180' filter='url(%23g)'/%3E%3C/svg%3E");
  --grain-deep:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='g'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.8' numOctaves='3' seed='7' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 .1 0 0 0 0 .05 0 0 0 0 .35 0 .9 0 0 -.4'/%3E%3C/filter%3E%3Crect width='180' height='180' filter='url(%23g)'/%3E%3C/svg%3E");
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-offset);scroll-behavior:smooth}
body{margin:0;font-family:var(--font-body);font-size:16px;line-height:1.6;color:var(--text);background-color:var(--bg);background-image:var(--grain-paper);-webkit-font-smoothing:antialiased;overflow-x:clip}
html.nav-open{overflow:hidden}
[hidden]{display:none!important}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
button,select,input,textarea{color:var(--text)}
button{background:var(--bg-panel);border:1px solid var(--border)}
img{display:block;max-width:100%;height:auto}
svg{flex-shrink:0}
fieldset{min-width:0}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px}
h1,h2,h3,h4,p,ul,ol,blockquote,figure{margin-top:0}
h1,h2,h3{overflow-wrap:break-word;text-wrap:balance}
h1{font-family:var(--font-display);font-size:clamp(52px,4.6vw,66px);line-height:1.12;letter-spacing:-.02em}
h2{font-size:clamp(28px,3vw,40px);line-height:1.25;letter-spacing:-.015em}
h3{font-size:22px;line-height:1.4}
p{margin-bottom:1.2em}
small{font-size:13px}
code{font-family:var(--font-mono);font-size:.88em;overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:20px;background:var(--bg-panel-2);border:1px solid var(--border);border-radius:var(--radius-card)}
pre code{overflow-wrap:normal;white-space:pre}
.wrap{width:100%;max-width:var(--content-width);margin-inline:auto;padding-inline:var(--gutter)}
.reading-wrap{width:100%;max-width:var(--reading-width);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:var(--section-space);padding-bottom:var(--section-space)}
.section-heading{max-width:760px;margin-bottom:32px}
.section-heading p{color:var(--text-muted)}
.grid{display:grid;gap:24px}
.grid>*{min-width:0}
.grid-three{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-five{grid-template-columns:repeat(5,minmax(0,1fr))}
.stack{display:grid;gap:20px;min-width:0}
.panel,.card{min-width:0;padding:28px;border:1px solid var(--border);border-radius:var(--radius-card);background:var(--bg-panel);box-shadow:inset 0 1px 0 var(--page),0 22px 46px -30px var(--shadow-tint)}
.panel-inset{background:var(--bg-panel-2);box-shadow:inset 0 1px 3px var(--shadow-warm)}
.muted{color:var(--text-muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.no-break{white-space:nowrap}
.defs{position:absolute;width:0;height:0;overflow:hidden}
.icon{width:24px;height:24px}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.skip-link{position:absolute;top:8px;left:16px;z-index:100;padding:8px 16px;background:var(--bg-panel);color:var(--accent);border-radius:var(--radius-sm);transform:translateY(-160%)}
.skip-link:focus{transform:none}
.btn,.btn-secondary,.btn-primary{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:44px;padding:10px 22px;border:1px solid var(--border-strong);border-radius:var(--radius-pill);font-weight:600;line-height:1.4;white-space:nowrap;flex-shrink:0}
.tabs .tab-next{display:inline-flex;align-items:center;justify-content:center}
.btn-primary{color:var(--on-accent);background:var(--ink);border-color:var(--ink);box-shadow:0 16px 30px -20px var(--shadow-cta)}
.btn,.btn-secondary{color:var(--text);background:var(--bg-panel)}
.btn:hover,.btn-secondary:hover,.btn-ghost:hover{border-color:var(--accent);color:var(--accent-dark)}
.btn-primary:hover,.btn-main:hover{background:var(--text)}
button:disabled,.btn[aria-disabled="true"]{cursor:not-allowed;opacity:.55}
.btn[aria-disabled="true"]{pointer-events:none}
.text-link{display:inline-flex;align-items:center;gap:8px;min-height:32px;color:var(--accent-dark);text-decoration:underline;text-underline-offset:4px}
.btn-main{display:inline-flex;align-items:center;gap:14px;height:56px;padding:0 22px 0 7px;border:0;border-radius:var(--radius-pill);background:var(--ink);color:var(--on-accent);font-size:17px;font-weight:600;letter-spacing:.01em;white-space:nowrap;flex-shrink:0;box-shadow:0 18px 34px -16px var(--shadow-cta),0 4px 10px -6px color-mix(in srgb,var(--ink) 50%,transparent),inset 0 1px 0 color-mix(in srgb,var(--page) 14%,transparent)}
.btn-tile{display:grid;place-items:center;width:42px;height:42px;flex-shrink:0;border-radius:var(--radius-tile);background:linear-gradient(140deg,var(--accent) 12%,var(--coral) 100%);box-shadow:inset 0 1px 0 color-mix(in srgb,var(--page) 40%,transparent),inset 0 -6px 12px -6px color-mix(in srgb,var(--accent-dark) 60%,transparent)}
.btn-tile svg{width:24px;height:24px}
.btn-arrow{width:18px;height:18px;flex-shrink:0}
.btn-ghost{display:inline-flex;align-items:center;justify-content:center;height:56px;padding:0 28px;border-radius:var(--radius-pill);background:var(--bg-panel);border:1px solid var(--border-strong);color:var(--text);font-size:16px;font-weight:600;white-space:nowrap;flex-shrink:0;box-shadow:inset 0 1px 0 var(--page),0 10px 22px -18px var(--shadow-tint-strong)}
.cta-row{display:flex;justify-content:center;flex-wrap:wrap;gap:14px;margin-top:26px}
.reveal{transition:opacity var(--reveal-time) var(--ease-out),transform var(--reveal-time) var(--ease-out)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-width:0;min-height:120px;max-width:100%;overflow:hidden;margin-block:24px}
#server-status>*{min-width:0;max-width:100%}
#server-status+*{margin-top:32px}

/* The top strip does not create a fixed-position containing block. */
#site-header{position:relative;z-index:50;min-height:var(--header-height)}
.topband{position:relative;z-index:50;background-color:var(--accent);background-image:var(--grain-light),var(--grain-deep);color:var(--on-accent)}
.topband::after{content:"";position:absolute;left:0;right:0;top:100%;height:8px;background-color:var(--accent);background-image:var(--grain-light),var(--grain-deep);mask:radial-gradient(circle at 7px 0,var(--mask-ink) 6.6px,transparent 7.2px) 0 0/14px 8px repeat-x,linear-gradient(var(--mask-ink),var(--mask-ink)) 0 0/100% 2px no-repeat}
.topbar{display:flex;align-items:center;flex-wrap:nowrap;height:var(--header-height);gap:0}
.brand{display:inline-flex;align-items:center;gap:9px;flex:none}
.brand-mark{width:28px;height:28px;object-fit:contain;flex:none}
.brand-word{font-size:19px;font-weight:700;letter-spacing:-.01em}
.brand-zh{font-size:15px;font-weight:500;color:var(--text-muted)}
.mainnav{display:flex;align-items:center;flex:1;min-width:0;margin-left:48px}
.mainnav ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:30px}
.mainnav li{min-width:0}
.mainnav a{display:inline-flex;align-items:center;min-height:32px;font-size:15px;font-weight:500;color:color-mix(in srgb,var(--on-accent) 80%,transparent);white-space:nowrap}
.mainnav a:hover,.mainnav a[aria-current="page"]{color:var(--on-accent)}
.mainnav a[aria-current="page"]{font-weight:700}
.topbar-end{display:flex;align-items:center;gap:20px;margin-left:auto;flex-shrink:0}
.lang-switch{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:5px;min-width:44px;min-height:36px;width:auto;background:none;border:0;padding:4px 0;cursor:pointer;font-size:14px;font-weight:500;white-space:nowrap;color:color-mix(in srgb,var(--on-accent) 82%,transparent)}
.lang-name{white-space:nowrap}
.lang-panel{position:absolute;right:0;top:calc(100% + 12px);z-index:80;width:184px;padding:8px;background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--radius-card);box-shadow:0 20px 40px var(--shadow-tint);color:var(--text)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--radius-sm);font-size:14px}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--accent-wash);color:var(--accent-dark)}
.login{display:inline-flex;align-items:center;justify-content:center;height:36px;padding:0 20px;border-radius:var(--radius-pill);background:var(--on-accent);color:var(--accent-dark);font-size:14px;font-weight:700;white-space:nowrap;box-shadow:0 8px 18px -10px color-mix(in srgb,var(--ink) 55%,transparent),inset 0 -1px 0 color-mix(in srgb,var(--accent) 14%,transparent)}
.topband :focus-visible{outline-color:var(--on-accent)}
.lang-panel :focus-visible{outline-color:var(--accent)}
.menu-toggle{display:none;align-items:center;justify-content:center;flex-direction:column;gap:5px;min-width:44px;min-height:44px;border:0;background:none;color:var(--on-accent);padding:10px}
.menu-line{display:block;width:20px;height:2px;background:currentColor}
.menu-toggle[aria-expanded="true"] .menu-line:first-child{transform:translateY(7px) rotate(45deg)}
.menu-toggle[aria-expanded="true"] .menu-line:nth-child(2){opacity:0}
.menu-toggle[aria-expanded="true"] .menu-line:last-child{transform:translateY(-7px) rotate(-45deg)}
.nav-drawer{position:fixed;z-index:45;top:var(--header-height);right:0;left:0;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;padding:24px var(--gutter);background:var(--bg-panel);color:var(--text)}
.nav-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:12px 16px;border-radius:var(--radius-sm)}
.nav-drawer a:hover,.nav-drawer a[aria-current]{color:var(--accent-dark);background:var(--accent-wash)}
.drawer-label{margin:24px 16px 8px;font-size:13px;color:var(--text-muted)}
.nav-veil{position:fixed;z-index:40;inset:var(--header-height) 0 0;background:var(--veil);border:0;width:100%;padding:0}
.site-footer{padding-top:64px;padding-bottom:28px;background:var(--bg-panel-2);border-top:1px solid var(--border);overflow-x:clip}
.footer-grid{display:grid;grid-template-columns:1.25fr 1fr 1fr;gap:48px}
.footer-brand p{max-width:30em;margin-top:20px;color:var(--text-muted);font-size:14px}
.footer-heading{margin-bottom:16px;font-size:14px;font-weight:700}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px 16px}
.footer-links a,.footer-search a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:32px;font-size:14px}
.footer-links a:hover,.footer-search a:hover,.footer-languages a:hover,.footer-legal a:hover{color:var(--accent-dark);text-decoration:underline;text-underline-offset:4px}
.footer-search{display:grid;gap:4px}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 24px;padding-top:32px;margin-top:32px;border-top:1px solid var(--border)}
.footer-languages a[aria-current]{font-weight:700;color:var(--accent-dark)}
.footer-bottom{display:flex;justify-content:space-between;flex-wrap:wrap;gap:16px;padding-top:24px;margin-top:24px;border-top:1px solid var(--border);color:var(--text-muted);font-size:13px}
.footer-bottom p{margin:0}
.footer-legal{display:flex;flex-wrap:wrap;gap:16px}
.prose{min-width:0;overflow-wrap:break-word}
.prose p,.prose li{line-height:1.85}
.prose h2{margin-top:2.4em;margin-bottom:.8em}
.prose h3{margin-top:1.8em}
.prose a:not(.btn):not(.btn-main):not(.btn-secondary):not(.toc-tabs a){color:var(--accent-dark);text-decoration:underline;text-underline-offset:3px}
.prose li+li{margin-top:.5em}
.prose img{border-radius:var(--radius-card)}
.prose blockquote{margin-inline:0;padding:20px 24px;background:var(--bg-panel-2);border-left:3px solid var(--accent)}
.page-heading{padding-top:64px;padding-bottom:40px}
.page-heading p{max-width:48em;color:var(--text-muted)}
@media(max-width:1279px){
  .mainnav{margin-left:28px}
  .mainnav ul{gap:20px}
  .mainnav a{font-size:14px}
  .topbar-end{gap:14px}
}
@media(max-width:1100px){
  .mainnav{display:none}
  .menu-toggle{display:flex}
  .topbar-end{margin-left:auto;gap:12px}
}
@media(min-width:1101px){
  .nav-drawer,.nav-veil{display:none!important}
}
@media(max-width:768px){
  :root{--gutter:24px;--section-space:56px}
  h1{font-size:clamp(28px,6vw,40px)}
  h2{font-size:clamp(26px,4.5vw,34px)}
  .grid-three{grid-template-columns:1fr}
  .grid-five{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:1fr 1fr;gap:32px}
  .footer-brand{grid-column:1/-1}
  .page-heading{padding-top:48px}
}
@media(max-width:640px){
  :root{--gutter:16px}
  .no-break{white-space:normal}
  .tilt,.tilt-card,[data-tilt]{transform:none}
  .decoration,.stripe-halo{max-width:100%}
  .topbar-end{margin-left:auto;gap:8px}
  .brand{gap:6px}
  .brand-mark{width:24px;height:24px}
  .brand-word{font-size:16px}
  .lang{font-size:11px;gap:2px}
  .login{padding-inline:12px;font-size:13px}
  .panel,.card{padding:22px}
  .footer-grid{grid-template-columns:1fr}
  .footer-brand{grid-column:auto}
  .footer-bottom{display:grid}
  .page-heading{padding-bottom:24px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none;transition:none}
}