:root{
  --bg:#F6EEE2;--paper-hi:#FBF6EE;--paper-lo:#F1E6D5;
  --panel:#FCF8F1;--panel-2:#EDE3D3;--border:#DDD0BC;--line-strong:#BBA98F;
  --accent:#C4592E;--accent-dark:#9A4220;--text:#241B15;--text-2:#3A2D24;--muted:#6E6052;
  --success:#3F7D4E;--success-ring:rgba(63,125,78,.18);--warn:#B9801C;--error:#B23A2E;
  --sky-1:#FBF1E2;--sky-2:#F2C9A0;--sky-3:#D99A86;
  --sun-core:#FFE7B9;--sun-rim:#F2B07C;--glow:#FFF5E4;--cloud:#FFF9F0;
  --sea-1:#5B6A8C;--sea-1b:#4C5A7C;--sea-2:#34416A;--sea-2b:#2A365B;--sea-3:#1F2A44;--sea-3b:#172036;
  --dawn-a:#34416A;--dawn-m:#5A5670;--dawn-b:#86605A;
  --on-dark:#FFFBF5;--on-dark-2:rgba(255,251,245,.82);
  --flag-red:#B23A2E;--flag-white:#FCF8F1;--flag-blue:#34416A;--flag-edge:rgba(36,27,21,.14);
  --shadow-tint:rgba(196,89,46,.10);--shadow-tint-2:rgba(196,89,46,.14);--shadow-tint-3:rgba(154,66,32,.16);
  --shadow-deep:rgba(23,32,54,.45);
  --glass-light:rgba(252,248,241,.58);--glass-edge:rgba(255,251,245,.72);--glass-top:rgba(255,255,255,.85);
  --glass-dark:rgba(31,42,68,.38);--glass-dark-edge:rgba(255,251,245,.22);
  --ghost-fill:rgba(252,248,241,.08);--ghost-fill-2:rgba(252,248,241,.18);--ghost-edge:rgba(252,248,241,.58);
  --chip-fill:rgba(252,248,241,.5);--chip-edge:rgba(36,27,21,.16);--frame-edge:rgba(255,251,245,.28);
  --scrim:rgba(31,42,68,.72);--scrim-2:rgba(23,32,54,.92);--clear:transparent;
  --r:2px;--r-round:50%;--r-flag:2.5px;
  --font-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Microsoft YaHei",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,-apple-system,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --weight-body:400;--weight-title:500;--weight-strong:600;
  --gutter:24px;--wrap:1440px;--reading:800px;--header-height:64px;--anchor-gap:88px;--toc-offset:16px;--toc-landing:104px;
  --space-section:80px;--shadow-panel:0 24px 64px -16px var(--shadow-tint);
  --ease:cubic-bezier(.2,.7,.3,1);--fast:200ms;--reveal-time:350ms;
  --grain:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 .14 0 0 0 0 .106 0 0 0 0 .082 0 0 0 1.1 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  --grain-op:.04;
}
*,*::before,*::after{box-sizing:border-box}
html{max-width:100%;overflow-x:clip;scroll-padding-top:var(--anchor-gap);scroll-behavior:smooth}
html.nav-open{overflow:hidden}
body{margin:0;min-width:320px;max-width:100%;overflow-x:clip;background:var(--bg);color:var(--text);font:var(--weight-body) 16px/1.6 var(--font-body);-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
body::after{content:"";position:fixed;inset:0;z-index:60;pointer-events:none;background-image:var(--grain);background-size:180px 180px;opacity:var(--grain-op);mix-blend-mode:multiply}
[hidden]{display:none!important}
img,svg,video{max-width:100%;vertical-align:middle}
img{height:auto}
button,input,select,textarea{font:inherit;color:inherit}
button{cursor:pointer}
a{color:inherit;text-underline-offset:3px}
a:hover{text-decoration-thickness:2px}
button,a,summary,input,select,textarea{touch-action:manipulation}
:where(a,button,summary,input,select,textarea,[tabindex]):focus-visible{outline:2px solid var(--accent);outline-offset:3px}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:var(--weight-title);line-height:1.25;margin:0 0 20px;letter-spacing:-.02em;overflow-wrap:break-word;text-wrap:balance}
h1{font-size:clamp(52px,4.75vw,68px);line-height:1.1}
h2{font-size:clamp(28px,3vw,40px)}
h3{font-size:24px}
h4{font-size:19px}
p{margin:0 0 20px}
strong{font-weight:var(--weight-strong)}
ul,ol{padding-left:1.5em}
li+li{margin-top:6px}
code,kbd,pre,.num,.mono{font-family:var(--font-mono)}
code{overflow-wrap:anywhere;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)}
pre code{overflow-wrap:normal;white-space:pre}
figure{margin:0}
hr{border:0;border-top:1px solid var(--border);margin:32px 0}
.wrap{width:100%;max-width:var(--wrap);margin-inline:auto;padding-inline:var(--gutter)}
.reading-wrap{width:100%;max-width:var(--reading);margin-inline:auto;padding-inline:var(--gutter)}
.sec{padding-top:var(--space-section);padding-bottom:var(--space-section)}
.grid{display:grid;gap:24px}
.grid>* , .panel>* , .masthead>*{min-width:0}
.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-5{grid-template-columns:repeat(5,minmax(0,1fr))}
.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}
.muted{color:var(--muted)}
.small{font-size:14px}
.section-intro{max-width:48em;color:var(--muted)}
.sec-no{margin:0 0 12px;font:13px/1.6 var(--font-mono);color:var(--accent);letter-spacing:.06em}
.sheet{background:linear-gradient(180deg,var(--paper-hi),var(--paper-lo))}
.card,.surface{padding:28px;background:var(--panel);border:1px solid var(--border);border-radius:var(--r);box-shadow:var(--shadow-panel)}
.panel{display:grid;grid-template-columns:5fr 7fr;gap:48px;align-items:center;margin-top:24px;padding:48px;background:var(--panel);border-radius:var(--r);box-shadow:inset 0 0 0 1px var(--border),var(--shadow-panel)}
.panel p{margin:16px 0 0;color:var(--muted);line-height:1.75}
.panel .foot{margin-top:24px;padding-top:16px;border-top:1px solid var(--border);font:12.5px/1.7 var(--font-mono);color:var(--text)}
.panel-art{overflow:hidden;border-radius:var(--r);box-shadow:0 18px 44px -18px var(--shadow-tint-2)}
.panel-art svg{display:block;width:100%;height:auto}
.panel-art figcaption{display:flex;justify-content:space-between;gap:12px;padding:10px 14px;background:var(--panel-2);font-size:12px;color:var(--muted)}
.cta-row{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:50px;padding:10px 24px;border:0;border-radius:var(--r);font:var(--weight-title) 16px/1.5 var(--font-body);text-decoration:none;white-space:nowrap;flex-shrink:0;transition:background-color var(--fast) var(--ease),color var(--fast) var(--ease),box-shadow var(--fast) var(--ease)}
.btn-primary{background:var(--text);color:var(--on-dark)}
.btn-primary:hover,.btn-primary.is-hover{background:var(--accent);color:var(--on-dark)}
.btn-secondary{background:var(--panel-2);color:var(--text);flex-shrink:0;white-space:nowrap}
.btn-secondary:hover{background:var(--border)}
.btn-light{background:var(--on-dark);color:var(--text)}
.btn-light:hover{background:linear-gradient(180deg,var(--accent),var(--accent-dark));color:var(--on-dark)}
.btn-ghost{background:var(--ghost-fill);color:var(--on-dark);box-shadow:inset 0 0 0 1px var(--ghost-edge);backdrop-filter:blur(8px)}
.btn-ghost:hover{background:var(--ghost-fill-2)}
.btn:disabled,.btn[aria-disabled="true"]{cursor:not-allowed;background:var(--panel-2);color:var(--muted);box-shadow:inset 0 0 0 1px var(--border)}
.btn.is-focus{outline:2px solid var(--accent);outline-offset:3px}
.chev{font-size:20px;line-height:1}
.notice{display:flex;align-items:center;justify-content:center;gap:16px;min-height:40px;padding:6px 24px;background:linear-gradient(90deg,var(--dawn-a),var(--dawn-m) 52%,var(--dawn-b));color:var(--on-dark);font-size:14px;letter-spacing:.01em;text-align:center}
.notice p{margin:0}
.notice .num{font-size:13px}
.notice-link{display:inline-flex;align-items:center;min-height:26px;text-decoration:underline;text-decoration-thickness:1px;white-space:nowrap}
.notice-btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:26px;padding:2px 12px;background:var(--on-dark);color:var(--text);border-radius:var(--r);font-size:13px;font-weight:var(--weight-title);text-decoration:none;white-space:nowrap}
.notice-btn:hover{background:var(--panel-2)}
#site-header{position:relative;z-index:40;background:var(--paper-hi)}
.masthead{position:relative;z-index:43;display:grid;grid-template-columns:auto minmax(0,1fr) auto;align-items:center;gap:24px;min-height:var(--header-height);padding:0 24px;background:var(--paper-hi)}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;font:var(--weight-strong) 19px/1.3 var(--font-display);letter-spacing:-.015em;color:var(--text);white-space:nowrap}
.brand img{display:block;width:32px;height:32px;flex-shrink:0}
.brand-zh{font-weight:var(--weight-body);color:var(--muted);font-size:14px}
.primary{min-width:0}
.primary ul{display:flex;align-items:center;justify-content:center;list-style:none;margin:0;padding:0;font-size:14px;gap:0}
.primary li{display:flex;align-items:center;margin:0}
.primary li+li::before{content:"·";color:var(--line-strong);margin:0 clamp(5px,.83vw,12px);font-weight:var(--weight-strong)}
.primary a{display:inline-flex;align-items:center;min-height:36px;color:var(--muted);text-decoration:none;white-space:nowrap}
.primary a:hover{color:var(--text)}
.primary a[aria-current="page"]{color:var(--text);font-weight:var(--weight-title);box-shadow:inset 0 -1px 0 var(--text)}
.mast-end{display:flex;align-items:center;gap:12px;flex-shrink:0}
.login{display:inline-flex;align-items:center;justify-content:center;min-height:36px;padding:6px 20px;background:var(--text);color:var(--on-dark);border-radius:var(--r);font-size:14px;font-weight:var(--weight-title);text-decoration:none;white-space:nowrap;flex-shrink:0}
.login:hover{background:var(--text-2)}
.lang{position:relative}
.lang-button,.lang summary{display:flex;align-items:center;justify-content:center;gap:6px;min-height:36px;width:auto;padding:6px 10px;border:0;background:var(--clear);font-size:14px;color:var(--muted);cursor:pointer;list-style:none;border-radius:var(--r);white-space:nowrap}
.lang-button span{white-space:nowrap}
.lang summary::-webkit-details-marker{display:none}
.lang-button:hover,.lang summary:hover{background:var(--panel-2);color:var(--text)}
.lang-button svg,.lang summary svg{width:16px;height:16px;flex-shrink:0}
.lang-panel{position:absolute;right:0;top:calc(100% + 6px);z-index:48;min-width:150px;list-style:none;margin:0;padding:6px;background:var(--panel);border-radius:var(--r);box-shadow:inset 0 0 0 1px var(--border),0 18px 40px -12px var(--shadow-tint-2)}
.lang-panel li{margin:0}
.lang-panel a{display:flex;align-items:center;min-height:40px;padding:8px 10px;text-decoration:none;color:var(--text);font-size:14px}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--panel-2)}
.menu-toggle{display:none;align-items:center;justify-content:center;flex-direction:column;gap:5px;min-width:44px;min-height:44px;border:1px solid var(--border);border-radius:var(--r);background:var(--panel);color:var(--text)}
.menu-line{display:block;width:20px;height:2px;background:currentColor;flex-shrink:0}
.mobile-drawer{position:fixed;top:var(--header-height);left:0;right:0;z-index:42;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;border-top:1px solid var(--border)}
.mobile-drawer a{display:flex;align-items:center;width:100%;min-height:44px;padding:10px 16px;text-decoration:none;border-bottom:1px solid var(--border)}
.mobile-drawer a[aria-current]{font-weight:var(--weight-strong);background:var(--panel-2)}
.drawer-languages{margin-top:24px;border-top:1px solid var(--line-strong)}
.menu-veil{position:fixed;inset:var(--header-height) 0 0;z-index:41;background:var(--scrim);border:0}
.site-footer{background:var(--panel-2);border-top:1px solid var(--border);padding-top:56px;padding-bottom:24px}
.footer-grid{display:grid;grid-template-columns:1.3fr 1fr 1fr 1fr;gap:40px}
.footer-grid>*{min-width:0}
.footer-brand p{max-width:27em;margin:20px 0 0;color:var(--muted);font-size:14px}
.footer-title{font-size:16px;margin:0 0 16px}
.footer-links{list-style:none;margin:0;padding:0}
.footer-links li{margin:0}
.footer-links a{display:inline-flex;align-items:center;min-height:32px;font-size:14px;color:var(--muted);text-decoration:none}
.footer-links a:hover{color:var(--text);text-decoration:underline}
.footer-bottom{display:flex;flex-wrap:wrap;justify-content:space-between;gap:16px;margin-top:40px;padding-top:24px;border-top:1px solid var(--line-strong);font-size:13px;color:var(--muted)}
.footer-bottom p{margin:0}
.footer-legal{display:flex;flex-wrap:wrap;gap:20px}
.footer-legal a{display:inline-flex;align-items:center;min-height:24px}
.reveal{transition:opacity var(--reveal-time) var(--ease),transform var(--reveal-time) var(--ease)}
.reveal.pending{opacity:0;transform:translateY(16px)}
.reveal.shown{opacity:1;transform:none}
#server-status{position:relative;display:block;min-height:80px;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:24px}
#server-status+*{margin-top:24px}
.decor-region{position:relative;overflow-x:clip}
@media(min-width:1101px) and (max-width:1300px){
  .masthead{gap:14px;padding-inline:20px}
  .primary ul{font-size:13px}
  .mast-end{gap:6px}
  .login{padding-inline:14px}
}
@media(max-width:1100px){
  .masthead{display:flex;flex-wrap:nowrap;gap:12px;min-height:var(--header-height);padding-inline:16px}
  .primary{display:none}
  .mast-end{margin-left:auto;gap:8px}
  .menu-toggle{display:flex}
}
@media(min-width:1101px){.mobile-drawer,.menu-veil{display:none!important}}
@media(max-width:900px){
  .grid-5{grid-template-columns:repeat(3,minmax(0,1fr))}
  .footer-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .panel{grid-template-columns:1fr;gap:32px;padding:32px}
}
@media(max-width:768px){
  :root{--gutter:16px;--space-section:56px}
  h1{font-size:clamp(28px,8vw,40px);line-height:1.15}
  .notice{flex-wrap:wrap;gap:8px 12px;font-size:13px;padding:8px 16px}
  .grid-3{grid-template-columns:1fr}
  .btn{min-height:46px;padding:10px 18px}
  .panel{padding:24px}
  .panel-art{order:-1}
  .footer-grid{gap:32px}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,[data-tilt]{transform:none}
  .decor-region>*{max-width:100%}
  .brand{font-size:16px;gap:7px}
  .brand img{width:28px;height:28px}
  .masthead{gap:6px;padding-inline:16px}
  .mast-end{gap:4px;margin-left:auto}
  .lang-button,.lang summary{font-size:12px;padding-inline:5px}
  .lang-button svg,.lang summary svg{display:none}
  .login{font-size:13px;padding-inline:12px}
  .brand-zh{display:none}
  .grid-5{grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid{grid-template-columns:1fr}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none;transition:none}
  .btn{transition:none}
}