:root{
  --bg:#F8F3E8;--bg-top:#FBF8F1;--bg-bottom:#F4ECDD;--panel:#FFFCF5;--panel-2:#EFE7D6;--border:#E2D7C2;--border-strong:#CDBFA4;
  --accent:#C4431F;--accent-dark:#8E2C12;--ink:#1E1A15;--ink-soft:#2F2921;--muted:#6B6154;--muted-2:#9C9180;
  --success:#3D7A3A;--warn:#B9840F;--error:#B3261E;--glow:#F3DCC2;--notice:#C9D6F2;
  --peri:#8FA6D8;--peri-deep:#2E3A5C;--peri-soft:#C9D6F2;--olive:#B3A872;--olive-deep:#4A4630;--olive-mid:#5C573A;--olive-cream:#EFE4B8;
  --oxblood:#5E1B12;--ochre:#D9B25A;--ochre-deep:#7A5A14;--cream:#FBF4E4;--cream-2:#F2E6CB;--on-ink:#FFFCF5;
  --hi-1:rgba(255,252,245,.44);--hi-2:rgba(255,252,245,.14);--veil:rgba(30,26,21,.32);
  --fl-red:#C63A33;--fl-white:#FFFCF5;--fl-blue:#283E7C;
  --r-card:28px;--r-stage:32px;--r-poster:16px;--r-win:14px;--r-sm:8px;--r-pill:999px;--r-logo:9px;
  --font-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --font-serif:Georgia,"Songti SC","STSong","Noto Serif SC","SimSun",serif;
  --weight-body:400;--weight-medium:500;--weight-bold:700;--weight-display:800;--weight-poster:900;
  --text-xs:12px;--text-sm:14px;--text-body:16px;--text-lede:20px;--text-h1:68px;--text-h2:40px;--text-h3:24px;
  --gutter:24px;--content:1200px;--head-height:64px;--anchor-offset:88px;--toc-offset:88px;--section-space:80px;
  --ease:cubic-bezier(.2,.7,.2,1);--time-fast:.2s;--time-reveal:.35s;
  --lift-warm:0 8px 18px -12px color-mix(in srgb,var(--ochre-deep) 40%,transparent);
  --shadow-panel:inset 0 1px 0 var(--hi-1),0 26px 40px -6px color-mix(in srgb,var(--ochre) 12%,transparent);
  --paper-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='.85' numOctaves='3' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 .23 0 0 0 0 .16 0 0 0 0 .1 .16 0 0 0 -.03'/%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:var(--text-body);line-height:1.7;font-weight:var(--weight-body);color:var(--ink);background:var(--bg);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
body::before{content:"";position:fixed;inset:0;z-index:60;pointer-events:none;mix-blend-mode:multiply;opacity:.55;background-image:var(--paper-grain);background-size:180px 180px}
a{color:inherit;text-underline-offset:3px}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button,summary,a{-webkit-tap-highlight-color:transparent}
button{border:0}
:focus-visible{outline:2px solid var(--accent-dark);outline-offset:4px}
[hidden]{display:none!important}
img{display:block;max-width:100%;height:auto}
svg{width:24px;height:24px;flex-shrink:0}
p{margin:0}
h1,h2,h3{font-family:var(--font-display);text-wrap:balance;color:var(--ink)}
h1{font-size:clamp(52px,5vw,var(--text-h1));font-weight:var(--weight-display);line-height:1.1;letter-spacing:-.02em;margin:0 0 24px}
h2{font-size:clamp(28px,3.3vw,var(--text-h2));font-weight:var(--weight-display);line-height:1.2;letter-spacing:-.02em;margin:0 0 20px}
h3{font-size:var(--text-h3);line-height:1.3;margin:0 0 16px}
ul,ol{padding-left:24px}
li::marker{color:var(--muted)}
code,kbd,pre{font-family:var(--font-mono)}
code{overflow-wrap:anywhere;background:var(--panel-2);border-radius:var(--r-sm);padding:2px 5px;font-size:.9em}
pre{max-width:100%;overflow-x:auto;padding:20px;background:var(--panel-2);border:1px solid var(--border);border-radius:var(--r-win)}
pre code{padding:0;background:transparent;overflow-wrap:normal;white-space:pre}
hr{border:0;border-top:1px solid var(--border);margin:32px 0}
.wrap{width:100%;max-width:var(--content);margin-inline:auto;padding-inline:var(--gutter);min-width:0}
.section{padding-top:var(--section-space);padding-bottom:var(--section-space)}
.stack>*+*{margin-top:24px}
.grid{display:grid;gap:24px;grid-template-columns:repeat(3,minmax(0,1fr))}
.grid>*{min-width:0}
.panel,.card{background:var(--panel);border:1px solid var(--border);border-radius:var(--r-card);padding:28px;box-shadow:var(--shadow-panel);min-width:0}
.panel-recess{background:var(--panel-2);border-radius:var(--r-stage);padding:32px;min-width:0}
.center{text-align:center}
.muted{color:var(--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;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.sprite{position:absolute;width:0;height:0;overflow:hidden}
.prose{max-width:800px;margin-inline:auto;overflow-wrap:anywhere}
.prose p,.prose ul,.prose ol{margin-bottom:24px}
.prose h2{margin-top:48px}
.prose h3{margin-top:32px}
.prose img{border-radius:var(--r-win)}
.prose a{font-weight:var(--weight-medium)}
.decor-region{position:relative;isolation:isolate;overflow-x:clip}
.reveal{transition:opacity var(--time-reveal) var(--ease),transform var(--time-reveal) var(--ease)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-height:64px;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status+*{margin-top:32px}

/* Shared navigation */
#site-header{position:relative;z-index:45;min-height:var(--head-height)}
.site-head{position:relative;z-index:45;max-width:1376px;height:var(--head-height);margin:0 auto;padding:0 32px;display:flex;align-items:center;gap:24px;flex-wrap:nowrap}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-family:var(--font-display);font-weight:800;font-size:18px;letter-spacing:-.02em;flex:none;white-space:nowrap}
.brand-mark{width:30px;height:30px;border-radius:var(--r-logo);flex-shrink:0;object-fit:contain}
.brand-zh{font-size:var(--text-sm);font-weight:var(--weight-medium);color:var(--muted)}
.nav{flex:1;min-width:0;display:flex;justify-content:center}
.nav ul{display:flex;align-items:center;gap:2px;list-style:none;margin:0;padding:0}
.nav li{min-width:0}
.nav a{display:block;padding:8px 13px;border-radius:var(--r-pill);color:var(--muted);font-size:14.5px;font-weight:500;text-decoration:none;white-space:nowrap;transition:color var(--time-fast),background-color var(--time-fast)}
.nav a:hover{color:var(--ink)}
.nav a[aria-current="page"]{color:var(--ink);font-weight:600;background:var(--panel-2);box-shadow:inset 0 0 0 1px var(--border)}
.head-tools{display:flex;align-items:center;gap:8px;flex-shrink:0}
.lang-picker{position:relative;flex-shrink:0}
.lang{min-height:38px;width:auto;display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:0 12px;border:0;border-radius:var(--r-pill);background:transparent;color:var(--ink-soft);font-size:14px;white-space:nowrap;cursor:pointer}
.lang:hover{background:var(--panel-2)}
.lang svg{width:16px;height:16px;color:var(--muted)}
.lang span{white-space:nowrap}
.lang-panel{position:absolute;right:0;top:calc(100% + 8px);z-index:55;width:188px;padding:8px;background:var(--panel);border:1px solid var(--border);border-radius:var(--r-win);box-shadow:var(--shadow-panel)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:none;border-radius:var(--r-sm);font-size:var(--text-sm)}
.lang-panel a:hover,.lang-panel a[aria-current]{background:var(--panel-2)}
.login{height:38px;display:inline-flex;align-items:center;justify-content:center;padding:0 18px;border-radius:var(--r-pill);background:var(--panel);color:var(--ink);font-size:14px;font-weight:600;text-decoration:none;white-space:nowrap;box-shadow:inset 0 0 0 1.5px var(--ink),var(--lift-warm);transition:background-color var(--time-fast)}
.login:hover{background:var(--panel-2)}
.menu-btn{display:none;min-width:44px;min-height:44px;place-items:center;border-radius:var(--r-pill);background:var(--panel);color:var(--ink);box-shadow:inset 0 0 0 1px var(--border)}
.menu-btn svg{width:20px;height:20px}
.menu-lines{fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round}
.nav-drawer{position:fixed;z-index:43;inset-inline:0;top:var(--head-height);height:calc(100dvh - var(--head-height));max-height:calc(100dvh - var(--head-height));padding:20px var(--gutter) 40px;background:var(--panel);overflow-y:auto;overscroll-behavior:contain}
.nav-drawer a{display:flex;width:100%;align-items:center;min-height:46px;padding:10px 16px;border-radius:var(--r-win);text-decoration:none}
.nav-drawer a:hover,.nav-drawer a[aria-current]{background:var(--panel-2);font-weight:600}
.drawer-languages{display:block;border-top:1px solid var(--border);margin-top:20px;padding-top:16px}
.nav-veil{position:fixed;z-index:42;inset:var(--head-height) 0 0;background:var(--veil)}
html.nav-open{overflow:hidden}
.toc-static{position:static!important}

/* Buttons */
.cta-row{margin-top:24px;display:flex;flex-wrap:wrap;justify-content:center;gap:12px}
.btn{height:56px;display:inline-flex;align-items:center;justify-content:center;gap:10px;padding:0 30px;border:0;border-radius:var(--r-pill);font-family:var(--font-body);font-size:17px;font-weight:600;letter-spacing:.02em;line-height:1.2;text-decoration:none;white-space:nowrap;flex-shrink:0;transition:transform var(--time-fast),box-shadow var(--time-fast),background-color var(--time-fast)}
.btn svg{width:18px;height:18px}
.btn-ink,.btn-primary{color:var(--on-ink);background:linear-gradient(180deg,var(--ink-soft),var(--ink));box-shadow:inset 0 1px 0 var(--hi-2),0 16px 30px -16px color-mix(in srgb,var(--ink) 60%,transparent)}
.btn-ink:hover,.btn-primary:hover{transform:translateY(-1px)}
.btn-line,.btn-secondary{color:var(--ink);background:var(--panel);box-shadow:inset 0 0 0 1.5px var(--ink),var(--lift-warm)}
.btn-line:hover,.btn-secondary:hover{background:var(--panel-2)}
.btn:active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{opacity:.5;cursor:not-allowed;transform:none}
.btn-small{height:44px;padding-inline:20px;font-size:var(--text-sm)}

/* Footer */
.site-foot{border-top:1px solid var(--border);background:var(--panel-2);padding-top:56px;padding-bottom:32px}
.foot-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:48px}
.foot-grid>*{min-width:0}
.foot-brand p{margin-top:20px;max-width:340px;color:var(--muted);font-size:var(--text-sm)}
.foot-title{font-size:var(--text-sm);font-weight:700;margin:0 0 16px}
.foot-links{display:flex;flex-wrap:wrap;gap:6px 18px;list-style:none;padding:0;margin:0}
.foot-links li{min-width:0}
.foot-links a{display:inline-flex;align-items:center;min-height:32px;font-size:var(--text-sm);text-decoration:none}
.foot-links a:hover{text-decoration:underline}
.foot-languages{display:flex;flex-wrap:wrap;gap:8px 20px;margin-top:32px;padding-top:24px;border-top:1px solid var(--border-strong)}
.foot-languages a{display:inline-flex;align-items:center;min-height:32px;font-size:var(--text-sm)}
.foot-bottom{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:16px;margin-top:24px;color:var(--muted);font-size:var(--text-xs)}
.foot-legal{display:flex;flex-wrap:wrap;gap:16px}
.foot-legal a{display:inline-flex;align-items:center;min-height:28px}

@media(max-width:1280px){
  .site-head{gap:14px;padding-inline:24px}
  .nav a{padding-inline:9px;font-size:13px}
  .head-tools{gap:4px}
}
@media(max-width:1120px){
  .nav{display:none}
  .head-tools{margin-left:auto}
  .menu-btn{display:grid}
  .foot-grid{gap:28px}
}
@media(min-width:1121px){
  .nav-drawer,.nav-veil{display:none!important}
  html.nav-open{overflow:auto}
}
@media(max-width:768px){
  h1{font-size:clamp(28px,6vw,40px)}
  h2{font-size:30px}
  .grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .foot-grid{grid-template-columns:1fr 1fr}
  .foot-brand{grid-column:1/-1}
}
@media(max-width:640px){
  :root{--gutter:16px;--section-space:48px}
  .no-break{white-space:normal}
  .wrap{padding-inline:var(--gutter)}
  .site-head{padding-inline:16px;gap:8px}
  .brand{font-size:16px;gap:6px}
  .brand-mark{width:26px;height:26px}
  .head-tools{margin-left:auto;gap:4px}
  .lang{font-size:12px;padding-inline:6px;gap:3px;min-height:44px}
  .lang svg{width:14px;height:14px}
  .login{height:36px;padding-inline:12px;font-size:13px}
  .menu-btn{min-width:44px;min-height:44px}
  .grid,.foot-grid{grid-template-columns:minmax(0,1fr)}
  .foot-brand{grid-column:auto}
  .panel,.card,.panel-recess{padding:20px}
  .tilt,.tilt-card,[data-tilt]{transform:none}
  .decor-region>*{max-width:100%}
  .btn{padding-inline:24px;font-size:16px}
  .foot-bottom{align-items:flex-start;flex-direction:column}
}
@media(max-width:359px){
  .site-head{gap:5px;padding-inline:12px}
  .brand{font-size:14px}
  .brand-mark{width:24px;height:24px}
  .lang{font-size:11px}
  .lang svg{display:none}
  .login{padding-inline:10px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending{opacity:1;transform:none;transition:none}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
}