:root{
  --bg:#E3EDF3;--bg-panel:#F6FAFC;--bg-panel2:#D5E3EC;--border:#C3D3DF;
  --accent:#17407D;--accent-dark:#0F2C5A;--text:#0F1C2E;--text-muted:#52637A;
  --success:#2A9474;--success-lift:#7FD8B4;--warn:#C68916;--error:#C5413A;
  --mist-top:#EEF4F8;--mist-bottom:#DCE8F0;--white:#FFFFFF;--bar:#1F2832;--bar-text:#DCE5EE;
  --arch-top:#2A5CA8;--arch-bottom:#1E4C92;--wave-1:#3767B0;--wave-2:#2858A0;--wave-3:#1A4384;--slab:#A9BFD4;
  --flag-red:#C8312C;--flag-white:#FFFFFF;--flag-navy:#2B3270;--flag-blue:#21468B;--flag-ring:rgba(15,28,46,.16);
  --on-dark:#FFFFFF;--on-dark-soft:rgba(255,255,255,.78);--on-dark-dim:rgba(255,255,255,.56);
  --on-dark-line:rgba(255,255,255,.16);--on-dark-fill:rgba(255,255,255,.10);--on-dark-edge:rgba(255,255,255,.38);
  --mint-halo:rgba(127,216,180,.24);--accent-tint:rgba(23,64,125,.08);--accent-line:rgba(23,64,125,.20);
  --atmo:rgba(23,64,125,.04);--glow:rgba(255,255,255,.17);--glow-soft:rgba(255,255,255,.06);
  --arch-rim:rgba(255,255,255,.14);--hl-edge:rgba(255,255,255,.6);
  --shade-soft:rgba(23,64,125,.10);--shade-panel:rgba(23,64,125,.14);
  --shade-deep:rgba(6,20,46,.42);--shade-deep-soft:rgba(6,20,46,.22);
  --clear:transparent;--mask-solid:#000;
  --font-display:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans','Apple SD Gothic Neo','Microsoft YaHei',system-ui,sans-serif;
  --font-body:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans','Malgun Gothic','Microsoft YaHei',system-ui,sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,'SFMono-Regular',Menlo,Consolas,monospace;
  --weight-body:400;--weight-medium:500;--weight-semibold:600;--weight-bold:700;--weight-heavy:800;
  --fs-micro:8.5px;--fs-tiny:9.5px;--fs-code:10.5px;--fs-label:11px;--fs-small:11.5px;
  --fs-xs:12px;--fs-caption:12.5px;--fs-compact:13px;--fs-item:13.5px;--fs-sm:14px;
  --fs-nav:14.5px;--fs-control:15px;--fs-body:16px;--fs-lede:16.5px;--fs-lg:18px;
  --fs-brand:19px;--fs-title:22px;--fs-number:26px;--fs-h3:24px;--fs-h2:clamp(28px,3vw,40px);
  --fs-h1:clamp(52px,4.5vw,68px);--fs-dock:64px;--fs-mobile-h1:36px;--fs-price:40px;
  --radius-panel:32px;--radius-window:20px;--radius-card:16px;--radius-chip:10px;
  --radius-scene:24px;--radius-route:14px;--radius-ticket:12px;--radius-pill:999px;--radius-round:50%;
  --wrap:1312px;--reading:800px;--gutter:64px;--header-height:64px;--notice-height:40px;
  --header-edge:104px;--anchor-offset:120px;--toc-offset:184px;
  --shadow-card:0 24px 60px -20px var(--shade-soft),inset 0 1px 0 var(--hl-edge);
  --shadow-dock:0 36px 80px -28px var(--shade-panel),0 14px 30px -14px var(--shade-panel),inset 0 1px 0 var(--on-dark-line);
  --shadow-float:inset 0 0 0 1px var(--hl-edge),0 18px 36px -14px var(--shade-deep),0 4px 10px -4px var(--shade-deep-soft);
  --duration:.2s;--reveal-duration:.35s;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:var(--anchor-offset);scroll-behavior:smooth}
html.nav-open{overflow:hidden}
body{margin:0;font-family:var(--font-body);font-size:var(--fs-body);font-weight:var(--weight-body);line-height:1.6;color:var(--text);background:var(--bg);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
button,a,summary{-webkit-tap-highlight-color:var(--accent-tint)}
button{background:var(--clear)}
a:focus-visible,button:focus-visible,summary:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,[tabindex]:focus-visible{outline:2px solid var(--accent);outline-offset:4px}
.dock a:focus-visible,.notice a:focus-visible{outline-color:var(--success-lift)}
button:disabled,.btn[aria-disabled="true"]{opacity:.55;cursor:not-allowed;pointer-events:none}
[hidden]{display:none!important}
img{max-width:100%;height:auto;vertical-align:middle}
svg{flex-shrink:0;vertical-align:middle}
p{margin:0 0 1.25em}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:var(--weight-bold);line-height:1.25;text-wrap:balance;overflow-wrap:break-word}
h1{font-size:var(--fs-h1);line-height:1.12;letter-spacing:-.02em;margin:0 0 24px}
h2{font-size:var(--fs-h2);margin:0 0 24px;letter-spacing:-.015em}
h3{font-size:var(--fs-h3);margin:0 0 16px}
h4{font-size:var(--fs-lg);margin:0 0 12px}
ul,ol{padding-left:1.5em}
li{margin-block:4px}
hr{border:0;border-top:1px solid var(--border);margin-block:32px}
code,kbd,pre{font-family:var(--font-mono)}
code{overflow-wrap:anywhere;font-size:.9em;background:var(--bg-panel2);border-radius:var(--radius-chip);padding:2px 5px}
pre{max-width:100%;overflow-x:auto;padding:24px;background:var(--accent-dark);color:var(--on-dark);border-radius:var(--radius-card)}
pre code{background:var(--clear);padding:0;white-space:pre;overflow-wrap:normal}
:where(main,section,article,aside,nav,div,li){min-width:0}
.wrap{width:100%;max-width:calc(var(--wrap) + var(--gutter)*2);margin-inline:auto;padding-inline:var(--gutter)}
.reading-wrap{max-width:calc(var(--reading) + var(--gutter)*2)}
.section{padding-top:80px;padding-bottom:80px}
.section-head{max-width:800px;margin-bottom:32px}
.kicker{font-family:var(--font-mono);font-size:var(--fs-xs);font-weight:var(--weight-semibold);letter-spacing:.08em;text-transform:uppercase;color:var(--accent);margin-bottom:12px}
.muted{color:var(--text-muted)}
.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}
.ico-stroke{fill:none;stroke:currentColor;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round}
.icon{width:20px;height:20px}
.panel,.card{background:var(--bg-panel);border:1px solid var(--hl-edge);border-radius:var(--radius-scene);box-shadow:var(--shadow-card);padding:32px}
.panel-inset{background:var(--bg-panel2);border:1px solid var(--border);border-radius:var(--radius-card);padding:24px}
.grid-cards{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.btn{display:inline-flex;align-items:center;justify-content:center;flex-shrink:0;gap:8px;min-height:52px;padding:0 28px;border:1px solid var(--clear);border-radius:var(--radius-pill);font-family:var(--font-body);font-size:var(--fs-body);font-weight:var(--weight-semibold);line-height:1.2;white-space:nowrap;transition:transform var(--duration),background var(--duration),border-color var(--duration),color var(--duration)}
.btn svg{width:18px;height:18px}
.btn-primary{background:var(--accent);color:var(--white);box-shadow:0 10px 24px -12px var(--shade-panel)}
.btn-primary:hover{background:var(--accent-dark);transform:translateY(-1px)}
.btn-secondary{border:1.5px solid var(--accent);color:var(--accent)}
.btn-secondary:hover{background:var(--accent-tint)}
.btn-light{background:var(--white);color:var(--accent-dark);box-shadow:0 12px 24px -10px var(--shade-deep),inset 0 -2px 0 var(--accent-tint)}
.btn-light:hover{transform:translateY(-1px)}
.btn-outline{border:1.5px solid var(--on-dark-edge);color:var(--on-dark)}
.btn-outline:hover{background:var(--on-dark-fill);border-color:var(--on-dark)}
.btn-small{min-height:44px;padding-inline:20px;font-size:var(--fs-sm)}
.btn:active{transform:translateY(0)}
.cta-row{display:flex;flex-wrap:wrap;gap:12px;margin-bottom:22px}
.notice{background:var(--bar);color:var(--bar-text);font-size:var(--fs-sm)}
.notice-in{min-height:var(--notice-height);display:flex;align-items:center;justify-content:center;gap:14px;padding-top:6px;padding-bottom:6px}
.notice-tag{display:inline-flex;align-items:center;justify-content:center;flex-shrink:0;height:24px;padding:0 11px;border:1.5px solid var(--success);border-radius:var(--radius-pill);color:var(--white);font-weight:var(--weight-semibold);font-size:var(--fs-caption);line-height:1}
.notice-link{color:var(--white);font-weight:var(--weight-medium);display:inline-flex;align-items:center;gap:6px;min-height:24px}
.notice-link:hover{text-decoration:underline;text-underline-offset:3px}
#site-header,.preview-header{position:sticky;top:0;z-index:100;background:var(--mist-top)}
.masthead-in{height:var(--header-height);display:flex;align-items:center;flex-wrap:nowrap;gap:28px}
.brand{display:inline-flex;align-items:center;gap:10px;flex-shrink:0;min-height:44px}
.brand img{width:32px;height:32px}
.brand-en{font-family:var(--font-display);font-weight:var(--weight-heavy);font-size:var(--fs-brand);letter-spacing:-.02em;color:var(--text)}
.brand-zh{font-size:var(--fs-compact);font-weight:var(--weight-medium);color:var(--text-muted);padding-left:10px;border-left:1px solid var(--border);line-height:1}
.tabs{flex:1;display:flex;justify-content:center;min-width:0}
.tabs ul{display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:2px}
.tabs li{margin:0;flex-shrink:0}
.nav-more{position:relative;flex-shrink:0}
.nav-more-toggle{display:flex;align-items:center;gap:6px;height:64px;padding-inline:12px;border:0;background:var(--clear);color:var(--text);font-size:var(--fs-nav);font-weight:var(--weight-medium);white-space:nowrap;cursor:pointer}
.nav-more-toggle:hover,.nav-more-toggle[aria-expanded="true"]{color:var(--accent)}
.nav-more-panel{position:absolute;top:100%;right:0;z-index:120;width:max-content;max-width:calc(100vw - 32px);padding:8px;background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--radius-card);box-shadow:var(--shadow-card)}
.tabs .nav-more-panel a{height:auto;min-height:44px;padding:10px 14px;white-space:normal;border-radius:var(--radius-chip)}
.tabs .nav-more-panel a::after{display:none}
.tabs .nav-more-panel a:hover{background:var(--bg)}
.tabs a{position:relative;display:flex;align-items:center;height:64px;padding:0 12px;font-size:var(--fs-nav);font-weight:var(--weight-medium);color:var(--text);white-space:nowrap;transition:color var(--duration)}
.tabs a::after{content:"";position:absolute;left:12px;right:12px;bottom:11px;height:3px;border-radius:var(--radius-pill);background:var(--accent);transform:scaleX(0);opacity:0;transition:transform var(--duration),opacity var(--duration)}
.tabs a:hover{color:var(--accent)}
.tabs a:hover::after{transform:scaleX(.4);opacity:.45}
.tabs a[aria-current="page"]{color:var(--accent);font-weight:var(--weight-semibold)}
.tabs a[aria-current="page"]::after{transform:scaleX(1);opacity:1}
.tools{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:44px;width:auto;padding:0 12px;border:0;background:var(--clear);font-size:var(--fs-sm);color:var(--text);border-radius:var(--radius-pill)}
.lang span{white-space:nowrap}
.lang:hover{background:var(--accent-tint)}
.lang svg{width:16px;height:16px;color:var(--text-muted)}
.lang-panel{position:absolute;top:calc(100% + 8px);right:0;z-index:120;min-width:184px;padding:8px;background:var(--bg-panel);border:1px solid var(--border);border-radius:var(--radius-card);box-shadow:var(--shadow-card)}
.lang-panel a{display:flex;align-items:center;width:100%;min-height:44px;padding:8px 14px;border-radius:var(--radius-chip);font-size:var(--fs-sm)}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--bg);color:var(--accent)}
.login{display:inline-flex;align-items:center;justify-content:center;flex-shrink:0;gap:7px;min-height:40px;padding:0 18px 0 15px;border:1.5px solid var(--accent);border-radius:var(--radius-pill);color:var(--accent);font-weight:var(--weight-semibold);font-size:var(--fs-nav);white-space:nowrap;transition:background var(--duration),color var(--duration)}
.login svg{width:17px;height:17px}
.login:hover{background:var(--accent);color:var(--white)}
.menu-toggle{display:none;align-items:center;justify-content:center;flex-direction:column;gap:5px;min-width:44px;min-height:44px;padding:10px;border:1px solid var(--border);border-radius:var(--radius-chip);color:var(--accent)}
.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)}
.mobile-drawer{position:fixed;top:var(--header-edge);right:0;left:0;z-index:99;height:calc(100dvh - var(--header-edge));max-height:calc(100dvh - var(--header-edge));overflow-y:auto;overscroll-behavior:contain;background:var(--bg-panel);padding:16px var(--gutter) 40px;border-top:1px solid var(--border)}
.mobile-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;border-radius:var(--radius-chip)}
.mobile-drawer a:hover,.mobile-drawer a[aria-current="page"],.mobile-drawer a[aria-current="true"]{background:var(--bg);color:var(--accent)}
.drawer-languages{border-top:1px solid var(--border);margin-top:16px;padding-top:16px}
.nav-veil{position:fixed;inset:var(--header-edge) 0 0;z-index:98;background:var(--shade-deep)}
.site-footer{border-top:1px solid var(--border);background:var(--bg-panel2);padding-top:56px;padding-bottom:24px}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr;gap:48px}
.footer-brand p{max-width:360px;margin-top:20px;color:var(--text-muted);font-size:var(--fs-sm)}
.footer-heading{font-size:var(--fs-sm);font-weight:var(--weight-bold);margin:0 0 12px;color:var(--accent)}
.footer-links{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px 16px}
.footer-links li{margin:0}
.footer-links a,.footer-languages a,.footer-legal a{display:inline-flex;align-items:center;min-height:32px;font-size:var(--fs-sm)}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover{color:var(--accent);text-decoration:underline;text-underline-offset:4px}
.footer-languages{display:flex;flex-wrap:wrap;gap:8px 24px;margin-top:32px;padding-block:16px;border-top:1px solid var(--border)}
.footer-languages a[aria-current="true"]{font-weight:var(--weight-bold);color:var(--accent)}
.footer-bottom{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px;padding-top:16px;border-top:1px solid var(--border);font-size:var(--fs-sm);color:var(--text-muted)}
.footer-bottom p{margin:0}
.footer-legal{display:flex;flex-wrap:wrap;gap:20px}
.prose{overflow-wrap:break-word}
.prose p,.prose li{line-height:1.9}
.prose h2{margin-top:48px}
.prose h3{margin-top:32px}
.prose a{color:var(--accent);text-decoration:underline;text-underline-offset:3px}
.prose img{border-radius:var(--radius-card)}
.reveal{transition:opacity var(--reveal-duration) ease,transform var(--reveal-duration) ease}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-width:0;max-width:100%;min-height:120px;overflow:hidden;margin-block:32px}
#server-status+*{margin-top:32px}
[data-counter]{display:inline-block;min-width:3ch;font-variant-numeric:tabular-nums;font-family:var(--font-mono)}
[data-counter="7"]{min-width:1ch}
[data-tilt]{transform-style:preserve-3d}
@media(min-width:1151px) and (max-width:1360px){
  .masthead-in{gap:16px}
  .tabs a,.nav-more-toggle{padding-inline:7px;font-size:var(--fs-compact)}
  .tools{gap:6px}
  .lang{padding-inline:8px}
}
@media(max-width:1150px){
  :root{--gutter:32px}
  .tabs{display:none}
  .masthead-in{gap:16px}
  .tools{margin-left:auto;gap:8px}
  .menu-toggle{display:inline-flex}
  .footer-grid{gap:28px}
}
@media(max-width:768px){
  :root{--gutter:24px;--fs-h1:40px;--fs-h2:30px}
  h1{font-size:var(--fs-h1)}
  .section{padding-top:48px;padding-bottom:48px}
  .grid-cards{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr 1fr}
  .footer-brand{grid-column:1/-1}
  .panel,.card{padding:24px}
}
@media(max-width:640px){
  :root{--gutter:16px;--fs-h1:36px}
  .no-break{white-space:normal}
  .wrap{padding-inline:var(--gutter)}
  .masthead-in{gap:6px}
  .brand{gap:6px}
  .brand img{width:26px;height:26px}
  .brand-en{font-size:var(--fs-body)}
  .brand-zh{display:none}
  .tools{margin-left:auto;gap:4px}
  .lang{padding-inline:6px;font-size:var(--fs-xs);gap:4px}
  .lang svg{width:14px;height:14px}
  .login{padding-inline:11px;min-height:38px;font-size:var(--fs-compact)}
  .login svg{display:none}
  .menu-toggle{padding:8px}
  .notice{font-size:var(--fs-xs)}
  .notice-in{gap:8px}
  .notice-tag{padding-inline:8px}
  .footer-grid{grid-template-columns:1fr;gap:24px}
  .footer-brand{grid-column:auto}
  .footer-bottom{align-items:flex-start;flex-direction:column}
  .panel,.card{padding:20px}
  [data-tilt],.tilt{transform:none!important}
  .decoration{max-width:100%;overflow-x:clip}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition-duration:0s!important;animation-duration:0s!important}
  .reveal,.reveal.pending{opacity:1;transform:none}
}