:root{
  --bg:#E4EAF5;
  --hero-top:#EDF1FA;
  --hero-bottom:#DCE4F2;
  --panel:#F6F8FD;
  --panel-2:#D8E0EF;
  --groove:#EEF2FA;
  --surface:#FFFFFF;
  --border:#C9D3E5;
  --border-soft:#DCE3F0;
  --accent:#E6603A;
  --accent-hi:#EE7C56;
  --accent-dark:#C24A26;
  --text:#1E2433;
  --muted:#596379;
  --faint:#6E7890;
  --success:#2E8B57;
  --success-soft:#E1F1E7;
  --iris:#4E5FC9;
  --iris-soft:#E5E8FA;
  --iris-line:rgba(78,95,201,.25);
  --warn:#C98A12;
  --error:#C8372D;
  --apricot:#F5EDEF;
  --apricot-line:#EBD9D6;
  --flag-red:#D3313B;
  --flag-blue:#2C3B80;
  --flag-white:#FFFFFF;
  --flag-edge:rgba(30,36,51,.14);
  --hl:rgba(255,255,255,.95);
  --white-30:rgba(255,255,255,.30);
  --white-70:rgba(255,255,255,.70);
  --glow-pool:rgba(246,248,253,.92);
  --nav-hover:rgba(216,224,239,.65);
  --bar-shade:rgba(216,224,239,.55);
  --ink-06:rgba(30,36,51,.06);
  --ink-10:rgba(30,36,51,.10);
  --muted-40:rgba(89,99,121,.40);
  --accent-08:rgba(230,96,58,.08);
  --accent-10:rgba(230,96,58,.10);
  --accent-12:rgba(230,96,58,.12);
  --accent-24:rgba(230,96,58,.24);
  --clear:transparent;
  --shadow-win:0 0 0 1px var(--border-soft),0 2px 4px var(--ink-06),0 24px 48px var(--accent-10);
  --shadow-float:0 0 0 1px var(--border-soft),0 2px 6px var(--ink-06),0 16px 36px var(--accent-10);
  --shadow-pop:0 0 0 1px var(--border-soft),0 18px 40px var(--ink-10);
  --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','Malgun Gothic','Microsoft YaHei',system-ui,sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,'SFMono-Regular',Menlo,Consolas,monospace;
  --r-win:24px;
  --r-card:28px;
  --r-pane:18px;
  --r-tile:14px;
  --r-row:9px;
  --r-menu:12px;
  --r-float:16px;
  --r-circle:50%;
  --r-pill:999px;
  --gutter:32px;
  --content-width:1200px;
  --header-height:64px;
  --anchor-space:80px;
  --toc-space:144px;
  --ease: cubic-bezier(.2,.65,.3,1);
  --fast:.15s;
  --reveal-time:.35s;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:var(--anchor-space)}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:16px;line-height:1.5;-webkit-font-smoothing:antialiased}
[hidden]{display:none!important}
img{display:block;max-width:100%;height:auto}
svg{vertical-align:middle;flex-shrink:0}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
a{color:inherit;text-underline-offset:.2em}
button,a,summary,input,select,textarea{-webkit-tap-highlight-color:var(--accent-12)}
:focus-visible{outline:2px solid var(--iris);outline-offset:3px}
h1,h2,h3,h4{font-family:var(--font-display);color:var(--text);text-wrap:balance}
h1{margin:0 0 24px;font-size:clamp(52px,4.5vw,68px);font-weight:800;line-height:1.12;letter-spacing:-.02em}
h2{margin:0 0 24px;font-size:clamp(28px,3vw,40px);font-weight:800;line-height:1.2;letter-spacing:-.02em}
h3{margin:0 0 16px;font-size:23px;line-height:1.35;letter-spacing:-.01em}
p{margin:0 0 20px}
code{font-family:var(--font-mono);font-size:.9em;overflow-wrap:anywhere}
pre{max-width:100%;overflow-x:auto;padding:20px;background:var(--groove);border:1px solid var(--border);border-radius:var(--r-tile)}
pre code{overflow-wrap:normal;white-space:pre}
table{border-collapse:collapse}
th,td{text-align:left}
section[id]{scroll-margin-top:var(--anchor-space)}
:where(main,section,article,aside,div,li){min-width:0}
.no-break{white-space:nowrap}
.wrap{width:100%;max-width:calc(var(--content-width) + var(--gutter)*2);margin-inline:auto;padding-inline:var(--gutter)}
.shell{width:100%;max-width:calc(var(--content-width) + var(--gutter)*2);margin-inline:auto;padding-inline:var(--gutter)}
.sec{padding-top:72px;padding-bottom:72px}
.section-head{max-width:780px;margin-bottom:32px}
.section-head p{color:var(--muted)}
.reading-wrap{max-width:860px;margin-inline:auto}
.prose{line-height:1.85;overflow-wrap:break-word}
.prose h2{margin-top:56px}
.prose h3{margin-top:32px}
.prose a{color:var(--iris)}
.prose li{margin-bottom:10px}
.muted{color:var(--muted)}
.mono{font-family:var(--font-mono);font-variant-numeric:tabular-nums}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
.skip{position:absolute;left:16px;top:-60px;z-index:100;padding:8px 14px;border-radius:var(--r-pill);background:var(--text);color:var(--surface);text-decoration:none;font-size:14px}
.skip:focus{top:12px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:52px;padding:0 30px;border:0;border-radius:var(--r-pill);font:650 16px var(--font-body);letter-spacing:.01em;text-decoration:none;white-space:nowrap;flex-shrink:0;transition:transform var(--fast),background-color var(--fast)}
.btn svg{width:18px;height:18px}
.btn:hover{transform:translateY(-1px)}
.btn-main,.btn-primary{color:var(--surface);background:linear-gradient(180deg,var(--accent-hi),var(--accent));box-shadow:inset 0 1px 0 var(--white-30),0 8px 18px var(--accent-24)}
.btn-main:hover,.btn-primary:hover,.btn.is-hover{background:linear-gradient(180deg,var(--accent),var(--accent-dark))}
.btn-line,.btn-secondary{color:var(--text);background:var(--clear);box-shadow:inset 0 0 0 1.5px var(--text)}
.btn-line:hover,.btn-secondary:hover{background:var(--panel)}
.btn-small{min-height:40px;padding-inline:20px;font-size:14px}
.btn:active,.btn.is-active{transform:translateY(1px)}
.btn:disabled,.btn[aria-disabled="true"]{opacity:.55;cursor:not-allowed;transform:none;box-shadow:none}
.btn.is-focus{outline:2px solid var(--iris);outline-offset:3px}
.card,.panel{padding:28px;border-radius:var(--r-card);background:var(--panel);border:1px solid var(--border-soft);box-shadow:inset 0 1px 0 var(--hl),0 12px 32px var(--accent-08)}
.panel{border-radius:var(--r-win)}
.grid-three{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
.grid-five{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:16px}
.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}
.decor-zone{position:relative;overflow-x:clip;max-width:100%}
#server-status{position:relative;display:block;min-height:160px;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:32px}
#server-status+*{margin-top:32px}

/* Shared header */
#site-header{position:relative;z-index:60}
.topbar{position:relative;z-index:60}
.topbar-in{position:relative;display:flex;align-items:center;flex-wrap:nowrap;height:var(--header-height);gap:28px}
.brand{display:inline-flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);font-family:var(--font-display);font-weight:800;font-size:19px;letter-spacing:-.02em;flex-shrink:0}
.brand img{width:28px;height:28px}
.desktop-nav{flex:1;min-width:0}
.nav-main{display:flex;align-items:center;gap:2px;margin:0;padding:0;list-style:none}
.nav-link{display:inline-flex;align-items:center;gap:6px;min-height:36px;padding:0 14px;border:0;border-radius:var(--r-pill);background:var(--clear);color:var(--muted);font-family:inherit;font-size:14.5px;font-weight:500;text-decoration:none;cursor:pointer;white-space:nowrap;transition:background-color var(--fast),color var(--fast)}
.nav-link:hover{color:var(--text);background:var(--nav-hover)}
.nav-link[aria-current="page"],.nav-link.is-current{color:var(--text);font-weight:650;background:var(--panel);box-shadow:inset 0 0 0 1px var(--border-soft)}
.nav-link svg{width:14px;height:14px}
.more{position:relative}
.more>summary{list-style:none}
.more>summary::-webkit-details-marker{display:none}
.more-menu{position:absolute;top:calc(100% + 8px);left:-8px;z-index:80;min-width:268px;margin:0;padding:8px;list-style:none;background:var(--surface);border-radius:var(--r-pane);box-shadow:var(--shadow-pop)}
.menu-link{display:flex;flex-direction:column;gap:2px;padding:10px 12px;border-radius:var(--r-menu);text-decoration:none;color:var(--text)}
.menu-link:hover,.menu-link[aria-current="page"]{background:var(--groove)}
.menu-title{font-size:14.5px;font-weight:650}
.menu-note{font-size:12.5px;color:var(--faint)}
.tools{display:flex;align-items:center;gap:8px;flex-shrink:0;margin-left:auto}
.language{position:relative}
.lang{display:inline-flex;align-items:center;justify-content:center;gap:6px;width:auto;min-width:44px;min-height:38px;padding:0 12px;border:0;border-radius:var(--r-pill);background:var(--clear);color:var(--muted);font-family:inherit;font-size:14px;font-weight:500;cursor:pointer}
.lang:hover{background:var(--nav-hover);color:var(--text)}
.lang-text{white-space:nowrap}
.lang svg{width:16px;height:16px}
.lang .chev{width:13px;height:13px}
.lang-panel{position:absolute;right:0;top:calc(100% + 10px);z-index:90;min-width:184px;padding:8px;background:var(--surface);border-radius:var(--r-pane);box-shadow:var(--shadow-pop)}
.lang-panel a{display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-row);text-decoration:none;color:var(--text);white-space:nowrap}
.lang-panel a:hover,.lang-panel a[aria-current="true"]{background:var(--groove);color:var(--iris)}
.login{display:inline-flex;align-items:center;justify-content:center;min-height:38px;padding:0 20px;border-radius:var(--r-pill);background:var(--text);color:var(--surface);font-size:14px;font-weight:650;text-decoration:none;white-space:nowrap;box-shadow:inset 0 1px 0 var(--white-30);transition:background-color var(--fast)}
.login:hover{background:var(--muted)}
.burger{display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;padding:8px;border:1px solid var(--border);border-radius:var(--r-pill);background:var(--panel);color:var(--text)}
.burger svg{width:22px;height:22px;fill:none;stroke:currentColor;stroke-width:2;stroke-linecap:round}
.nav-drawer{position:fixed;inset-inline:0;top:var(--header-height);z-index:55;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));padding:16px var(--gutter) 32px;background:var(--panel);overflow-y:auto;overscroll-behavior:contain;border-top:1px solid var(--border)}
.nav-drawer a{display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;border-radius:var(--r-row);text-decoration:none;color:var(--text)}
.nav-drawer a:hover,.nav-drawer a[aria-current="page"]{background:var(--panel-2)}
.drawer-languages{padding-top:16px;margin-top:16px;border-top:1px solid var(--border)}
.drawer-languages a[aria-current="true"]{color:var(--iris);font-weight:700}
.nav-veil{position:fixed;inset:var(--header-height) 0 0;z-index:50;border:0;background:var(--ink-10)}
html.nav-open{overflow:hidden}

/* Shared footer */
.site-footer{padding-top:56px;padding-bottom:28px;background:var(--groove);border-top:1px solid var(--border)}
.footer-grid{display:grid;grid-template-columns:1.2fr 1fr 1fr;gap:48px}
.footer-brand p{max-width:330px;margin-top:20px;color:var(--muted);font-size:14px;line-height:1.8}
.footer-title{margin:0 0 16px;font-size:15px;font-weight:700}
.footer-links{display:flex;flex-wrap:wrap;gap:8px 20px;margin:0;padding:0;list-style:none}
.footer-links a{display:inline-flex;align-items:center;min-height:30px;color:var(--muted);font-size:14px;text-decoration:none}
.footer-links a:hover{color:var(--iris);text-decoration:underline}
.footer-languages{display:flex;flex-wrap:wrap;gap:12px 24px;margin-top:36px;padding-top:24px;border-top:1px solid var(--border)}
.footer-languages a{display:inline-flex;align-items:center;min-height:30px;font-size:13px;color:var(--muted);text-decoration:none}
.footer-languages a[aria-current="true"]{color:var(--text);font-weight:700}
.footer-bottom{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:16px;margin-top:24px;color:var(--muted);font-size:13px}
.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:30px}

/* Icon and flag vocabulary */
.svg-defs{position:absolute;width:0;height:0;overflow:hidden}
.ico{width:18px;height:18px;fill:none;stroke:currentColor;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round}
.fw{fill:var(--flag-white)}
.fr{fill:var(--flag-red)}
.fb{fill:var(--flag-blue)}
.fe{fill:none;stroke:var(--flag-edge);stroke-width:1}
.flag{width:24px;height:16px}
.flag-sq{width:16px;height:16px}
.st-a{stop-color:var(--accent-hi)}
.st-b{stop-color:var(--accent-dark)}

@media(max-width:1100px){
  .topbar-in{gap:16px}
  .nav-link{padding-inline:10px}
}
@media(max-width:980px){
  .desktop-nav{display:none}
  .tools{margin-left:auto}
  .burger{display:inline-flex}
  .footer-grid{gap:28px;grid-template-columns:1fr 1fr}
  .footer-brand{grid-column:1/-1}
}
@media(min-width:981px){
  .nav-drawer,.nav-veil{display:none!important}
}
@media(max-width:768px){
  :root{--gutter:16px}
  h1{font-size:clamp(28px,6vw,40px)}
  h2{font-size:30px}
  .sec{padding-top:48px;padding-bottom:48px}
  .grid-three{grid-template-columns:1fr}
  .grid-five{grid-template-columns:repeat(2,minmax(0,1fr))}
  .decor-zone{max-width:100%}
  .footer-grid{grid-template-columns:1fr}
  .footer-brand{grid-column:auto}
}
@media(max-width:640px){
  .no-break{white-space:normal}
  .tilt,[data-tilt]{transform:none!important}
  .lang-text{display:none}
  .topbar-in{gap:8px}
  .tools{gap:4px;margin-left:auto}
  .brand{gap:7px;font-size:17px}
  .brand img{width:26px;height:26px}
  .login{padding-inline:14px}
  .lang{padding-inline:8px}
  .lang .chev{display:none}
  .btn{min-height:48px;padding-inline:24px}
  .card,.panel{padding:22px}
  .footer-bottom{align-items:flex-start;flex-direction:column}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition:none!important;animation:none!important}
  .reveal,.reveal.pending,.reveal.shown{opacity:1;transform:none}
}