:root{
  --c-bg:#F7F0E2;
  --c-paper-top:#FBF7EE;
  --c-paper-bottom:#F2E9D8;
  --c-panel:#FFFCF6;
  --c-white:#FFFFFF;
  --c-sunk:#EFE5D2;
  --c-border:#E2D6C0;
  --c-line-soft:rgba(226,214,192,.72);
  --c-accent:#5145D6;
  --c-accent-dark:#3B30AE;
  --c-text:#2A2119;
  --c-muted:#6E6253;
  --c-success:#2F8A57;
  --c-warn:#C98A1B;
  --c-error:#C2412F;
  --c-sand:#EADFCB;
  --c-mist:#DCD6E8;
  --c-umber:#7A5638;
  --c-umber-deep:#573A24;
  --c-umber-shadow:rgba(87,58,36,.42);
  --c-spine-shade:rgba(122,86,56,.10);
  --c-spine-core:rgba(122,86,56,.24);
  --c-page-edge:#E4D7BF;
  --c-apricot:rgba(240,184,132,.36);
  --c-sun:rgba(255,250,240,.9);
  --c-accent-06:rgba(81,69,214,.06);
  --c-accent-10:rgba(81,69,214,.10);
  --c-accent-12:rgba(81,69,214,.12);
  --c-accent-14:rgba(81,69,214,.14);
  --c-accent-18:rgba(81,69,214,.18);
  --c-accent-30:rgba(81,69,214,.30);
  --c-ink-06:rgba(42,33,25,.06);
  --c-ink-10:rgba(42,33,25,.10);
  --c-ink-16:rgba(42,33,25,.16);
  --c-veil:rgba(42,33,25,.42);
  --c-highlight:rgba(255,255,255,.80);
  --c-highlight-soft:rgba(255,255,255,.45);
  --c-highlight-22:rgba(255,255,255,.22);
  --c-panel-72:rgba(255,252,246,.72);
  --c-on-dark:#FBF7EE;
  --c-on-dark-muted:rgba(251,247,238,.74);
  --c-flag-red:var(--c-error);
  --c-flag-white:var(--c-panel);
  --c-flag-navy:#2E3768;
  --c-flag-gold:var(--c-warn);
  --c-flag-black:var(--c-text);
  --ph-hk-a:#F2DCC8;--ph-hk-b:#E7CFD6;--ph-hk-g:#D7BAA8;
  --ph-sg-a:#EEDFC9;--ph-sg-b:#D9DCD2;--ph-sg-g:#C6CBBB;
  --ph-jp-a:#F4E3D3;--ph-jp-b:#EBD2CF;--ph-jp-g:#D8BFB3;
  --ph-us-a:#F0D9BF;--ph-us-b:#E2D2E2;--ph-us-g:#CDB7A6;
  --ph-de-a:#E9E0D0;--ph-de-b:#D8D6E2;--ph-de-g:#C5C0BC;
  --ph-ch-a:#E6E6DC;--ph-ch-b:#D5DDE3;--ph-ch-g:#C1CBCE;
  --font-display:"Inter","Noto Sans SC","Noto Sans JP","Noto Sans KR","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","Noto Sans JP","Noto Sans KR","PingFang SC","Hiragino Sans","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --r-xs:3px;--r-sm:6px;--r-md:8px;--r-menu:10px;--r-album:12px;--r-page:7px;--r-photo:2px;--r-flag:4px;--r-tag:5px;--r-lg:14px;--r-xl:16px;--r-pill:999px;--r-circle:50%;
  --shadow-board:0 44px 80px -40px var(--c-accent-30),0 20px 44px -26px var(--c-accent-12);
  --shadow-card:0 1px 2px var(--c-ink-10),0 8px 18px -12px var(--c-ink-16);
  --shadow-float:0 18px 36px -18px var(--c-accent-30),0 2px 6px var(--c-ink-06);
  --shadow-cta:0 14px 26px -12px var(--c-accent-30),inset 0 1px 0 var(--c-highlight-22);
  --gutter:48px;--content-width:1280px;--header-height:72px;--anchor-offset:96px;--toc-offset:88px;--chapter-offset:164px;
  --space-section:80px;--speed-fast:.18s;--speed-reveal:.35s;
  --tex-grain: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='.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 .165 0 0 0 0 .129 0 0 0 0 .098 0 0 0 1 0'/%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;background:var(--c-bg);color:var(--c-text);font-family:var(--font-body);font-size:16px;line-height:1.6;-webkit-font-smoothing:antialiased;overflow-wrap:break-word}
body::before{content:"";position:fixed;inset:0;pointer-events:none;z-index:90;background-image:var(--tex-grain);opacity:.03;mix-blend-mode:multiply}
[hidden]{display:none!important}
a{color:var(--c-accent);text-decoration:none}
a:hover{text-decoration:underline;text-underline-offset:4px}
:where(a,button,summary,input,select,textarea,[tabindex]):focus-visible{outline:2px solid var(--c-accent);outline-offset:3px;border-radius:var(--r-sm)}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button:disabled{cursor:not-allowed}
img{max-width:100%;height:auto}
svg{flex-shrink:0;vertical-align:middle}
p,ul,ol,figure,blockquote{margin:0}
ul,ol{padding-left:1.5em}
h1,h2,h3,h4{font-family:var(--font-display);color:var(--c-text);text-wrap:balance}
h1{margin:0;font-size:clamp(52px,4.6vw,68px);font-weight:900;line-height:1.12;letter-spacing:-.02em}
h2{margin:0 0 24px;font-size:clamp(32px,3.5vw,46px);font-weight:800;line-height:1.2;letter-spacing:-.02em}
h3{margin:0 0 14px;font-size:24px;font-weight:750;line-height:1.35}
h4{margin:0 0 12px;font-size:18px}
code{font-family:var(--font-mono);font-size:.9em;overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:24px;border:1px solid var(--c-border);border-radius:var(--r-md);background:var(--c-sunk)}
pre code{white-space:pre;overflow-wrap:normal}
hr{border:0;border-top:1px solid var(--c-border);margin:32px 0}
.wrap{max-width:var(--content-width);margin-inline:auto;padding-inline:var(--gutter)}
.section{padding-top:var(--space-section);padding-bottom:var(--space-section)}
.section-heading{text-align:center;max-width:800px;margin:0 auto 40px}
.section-heading p{color:var(--c-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:24px;min-width:0}
.muted{color:var(--c-muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.no-break{white-space:nowrap}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.panel,.card{min-width:0;padding:28px;background:var(--c-panel);border:1px solid var(--c-border);border-radius:var(--r-lg);box-shadow:var(--shadow-float),inset 0 1px 0 var(--c-highlight)}
.panel--sunk{background:var(--c-sunk);box-shadow:inset 0 1px 3px var(--c-ink-06)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:52px;padding:14px 24px;border:1px solid transparent;border-radius:var(--r-md);font:600 16px/1.35 var(--font-body);text-align:center;flex-shrink:0;white-space:nowrap;transition:transform var(--speed-fast) ease,box-shadow var(--speed-fast) ease,background var(--speed-fast) ease}
.btn:hover{transform:translateY(-1px);text-decoration:none}
.btn:active{transform:translateY(1px)}
.btn--primary,.btn-primary{background:linear-gradient(135deg,var(--c-accent),var(--c-accent-dark));color:var(--c-white);box-shadow:var(--shadow-cta)}
.btn--primary:hover,.btn-primary:hover{background:var(--c-accent-dark)}
.btn--ghost{background:var(--c-panel);color:var(--c-text);border-color:var(--c-border);box-shadow:var(--shadow-card)}
.btn--ghost:hover{border-color:var(--c-accent)}
.btn--small{min-height:40px;padding:10px 16px;font-size:14px}
.btn:disabled,.btn[aria-disabled="true"]{background:var(--c-sunk);color:var(--c-muted);border-color:var(--c-border);box-shadow:none;transform:none;pointer-events:none}
.btn--sample-hover{background:var(--c-accent-dark);transform:translateY(-1px)}
.btn--sample-focus{outline:2px solid var(--c-accent);outline-offset:3px}
.notice{background:var(--c-text);color:var(--c-on-dark);font-size:13.5px;line-height:1.4}
.notice__inner{display:flex;align-items:center;justify-content:center;gap:10px;min-height:40px;padding:8px 24px;text-align:center}
.notice__icon{flex:none;color:var(--c-on-dark-muted)}
.notice__price{color:var(--c-on-dark-muted);font:12.5px var(--font-mono)}
.notice__link{display:inline-flex;align-items:center;min-height:24px;color:var(--c-on-dark);font-weight:600;text-decoration:underline;text-underline-offset:3px}
.masthead{background:var(--c-paper-top);border-bottom:1px solid var(--c-line-soft);position:relative;z-index:60}
.masthead__inner{display:flex;align-items:center;flex-wrap:nowrap;gap:40px;height:var(--header-height);position:relative}
.brand{display:inline-flex;align-items:center;gap:10px;color:var(--c-text);flex:none;white-space:nowrap}
.brand:hover{text-decoration:none}
.brand__mark{display:block;flex:none;width:34px;height:34px}
.brand__en{font-family:var(--font-display);font-weight:800;font-size:19px;letter-spacing:-.02em}
.brand__zh{font-size:13px;font-weight:500;color:var(--c-muted);padding-left:10px;border-left:1px solid var(--c-border);line-height:1}
.mainnav{flex:1;min-width:0}
.mainnav__list{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:2px}
.mainnav__link,.mainnav__more{display:inline-flex;align-items:center;gap:6px;min-height:38px;padding:0 14px;border-radius:var(--r-sm);color:var(--c-text);font:500 15px/1.4 var(--font-body);background:transparent;border:0;cursor:pointer;position:relative;white-space:nowrap}
.mainnav__link:hover,.mainnav__more:hover{background:var(--c-accent-06);text-decoration:none}
.mainnav__link[aria-current="page"],.menu-item[aria-current="page"]{color:var(--c-accent-dark);font-weight:650}
.mainnav__link[aria-current="page"]::after{content:"";position:absolute;left:14px;right:14px;bottom:4px;height:2px;border-radius:var(--r-pill);background:var(--c-accent)}
.mainnav__chev{color:var(--c-muted);transition:transform var(--speed-fast) ease}
.mainnav__group{position:relative;list-style:none}
.mainnav__more[aria-expanded="true"] .mainnav__chev{transform:rotate(180deg)}
.mainnav__menu[hidden]{display:none}
.mainnav__menu{position:absolute;top:calc(100% + 10px);left:-8px;width:320px;max-width:calc(100vw - 32px);padding:10px;background:var(--c-panel);border:1px solid var(--c-border);border-radius:var(--r-menu);box-shadow:var(--shadow-float);z-index:65}
.menu-sec+.menu-sec{margin-top:6px;padding-top:8px;border-top:1px dashed var(--c-border)}
.menu-sec__label{display:block;padding:4px 10px 6px;font:600 10.5px/1.4 var(--font-mono);letter-spacing:.12em;color:var(--c-muted)}
.menu-item{display:block;padding:8px 10px;border-radius:var(--r-sm);color:var(--c-text);min-height:44px}
.menu-item:hover{background:var(--c-accent-06);text-decoration:none}
.menu-item__title{display:block;font-size:14.5px;font-weight:600;line-height:1.4}
.menu-item__desc{display:block;font-size:12.5px;color:var(--c-muted);line-height:1.5}
.masthead__tools{display:flex;align-items:center;gap:14px;margin-left:auto;flex-shrink:0}
.language{position:relative}
.langswitch{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-width:44px;width:auto;min-height:38px;padding:0 12px;background:transparent;border:1px solid transparent;border-radius:var(--r-sm);color:var(--c-muted);font:500 14px/1.3 var(--font-body);cursor:pointer;white-space:nowrap}
.langswitch span{white-space:nowrap}
.langswitch:hover{border-color:var(--c-border);color:var(--c-text)}
.lang-panel{position:absolute;right:0;top:calc(100% + 10px);z-index:70;min-width:180px;padding:8px;background:var(--c-panel);border:1px solid var(--c-border);border-radius:var(--r-md);box-shadow:var(--shadow-float)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;color:var(--c-text);border-radius:var(--r-sm)}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--c-accent-10);color:var(--c-accent-dark);text-decoration:none}
.btn-login{display:inline-flex;align-items:center;justify-content:center;min-height:40px;padding:0 20px;border-radius:var(--r-md);background:var(--c-text);color:var(--c-on-dark);font:600 14.5px/1.4 var(--font-body);box-shadow:var(--shadow-card);white-space:nowrap;transition:transform var(--speed-fast) ease}
.btn-login:hover{transform:translateY(-1px);text-decoration:none}
.nav-toggle{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(--c-border);border-radius:var(--r-sm);background:var(--c-panel);color:var(--c-text)}
.nav-toggle__line{display:block;width:20px;height:2px;background:currentColor}
.mobile-drawer{position:fixed;left:0;right:0;top:var(--drawer-top,var(--header-height));height:calc(100dvh - var(--drawer-top,var(--header-height)));max-height:calc(100dvh - var(--drawer-top,var(--header-height)));overflow-y:auto;overscroll-behavior:contain;z-index:55;background:var(--c-panel);padding:20px var(--gutter) 40px;border-top:1px solid var(--c-border)}
.mobile-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 8px;color:var(--c-text);border-bottom:1px solid var(--c-border)}
.mobile-drawer a[aria-current="page"]{color:var(--c-accent);font-weight:700}
.mobile-drawer__label{display:block;margin-top:20px;font:12px var(--font-mono);color:var(--c-muted)}
html.nav-open{overflow:hidden}
.site-footer{background:var(--c-panel);border-top:1px solid var(--c-border);padding-top:56px;padding-bottom:32px}
.footer-grid{display:grid;grid-template-columns:1.2fr 1fr 1fr;gap:48px}
.footer-brand p{max-width:30em;margin-top:20px;color:var(--c-muted);font-size:14px}
.footer-title{font-size:15px;margin-bottom:16px}
.footer-links{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:6px 20px;list-style:none;margin:0;padding:0}
.footer-links a{display:inline-flex;align-items:center;min-height:32px;color:var(--c-text);font-size:14px}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 24px;margin-top:32px;padding-top:24px;border-top:1px dashed var(--c-border)}
.footer-languages a{display:inline-flex;align-items:center;min-height:32px;color:var(--c-muted);font-size:14px}
.footer-bottom{display:flex;flex-wrap:wrap;justify-content:space-between;gap:12px;margin-top:24px;font-size:13px;color:var(--c-muted)}
.footer-legal{display:flex;flex-wrap:wrap;gap:20px}
.footer-legal a{display:inline-flex;align-items:center;min-height:24px;color:var(--c-muted)}
.prose{min-width:0;max-width:880px}
.prose p{margin-bottom:20px;line-height:1.85}
.prose h2{margin-top:48px;font-size:32px}
.prose h3{margin-top:32px}
.prose ul,.prose ol{margin-bottom:24px}
.prose li+li{margin-top:8px}
.prose img{border-radius:var(--r-md)}
.reveal{transition:opacity var(--speed-reveal) ease,transform var(--speed-reveal) ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{display:block;position:static;min-width:0;max-width:100%;min-height:160px;overflow:hidden;margin-block:24px}
#server-status+*{margin-top:32px}
@media(min-width:769px){.mobile-drawer{display:none}}
@media(max-width:1180px){
  :root{--gutter:32px}
  .masthead__inner{gap:20px}
  .mainnav__link,.mainnav__more{padding-inline:9px;font-size:14px}
  .masthead__tools{gap:8px}
  .langswitch{padding-inline:8px}
}
@media(max-width:980px){
  .mainnav{display:none}
  .nav-toggle{display:inline-flex}
  .masthead__tools{margin-left:auto}
}
@media(max-width:768px){
  :root{--gutter:24px;--space-section:56px}
  h1{font-size:clamp(28px,7vw,40px);line-height:1.15}
  h2{font-size:32px}
  .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}
  .notice__price{display:none}
}
@media(max-width:640px){
  :root{--gutter:16px;--header-height:64px;--toc-offset:12px;--chapter-offset:100px}
  .wrap{padding-inline:var(--gutter)}
  .no-break{white-space:normal}
  .tilt,[data-tilt]{transform:none}
  .masthead__inner{gap:8px}
  .brand{gap:7px}
  .brand__mark{width:28px;height:28px}
  .brand__en{font-size:16px}
  .masthead__tools{gap:4px;margin-left:auto}
  .btn-login{min-height:38px;padding-inline:12px;font-size:13px}
  .langswitch{font-size:12px;padding-inline:6px;gap:4px}
  .langswitch svg{display:none}
  .nav-toggle{padding:9px;min-width:44px}
  .panel,.card{padding:20px}
  .footer-grid{grid-template-columns:1fr}
  .footer-brand{grid-column:auto}
  .notice__inner{padding-inline:16px;gap:8px;font-size:12px}
  .prose h2{font-size:28px}
  .decor,.hero{max-width:100%;overflow-x:clip}
}
@media(max-width:359px){
  .brand__en{font-size:14px}
  .brand__mark{width:24px;height:24px}
  .btn-login{padding-inline:9px}
  .langswitch{font-size:11px}
  .masthead__inner{gap:4px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation:none!important;transition:none!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}