:root {
  --bg:#FAFBFD;
  --bg-panel:#FFFFFF;
  --bg-panel2:#EFF2F5;
  --groove:#E4E8EE;
  --border:#D7DCE3;
  --border-strong:#C3CAD4;
  --accent:#1270E3;
  --accent-dark:#0B4FB0;
  --accent-sky:#7CC4FF;
  --accent-soft:#E3EEFC;
  --text:#22262C;
  --text-muted:#5A6270;
  --text-faint:#8A92A0;
  --nav-idle:#767F8D;
  --ink:#22262C;
  --ink-2:#2C3140;
  --success:#1F9D63;
  --success-soft:rgb(31 157 99 / .16);
  --warn:#E08A00;
  --error:#D23A3A;
  --indigo:#3B3DB8;
  --indigo-deep:#17185A;
  --candy-yellow:#FFCB1F;
  --candy-pink:#FFB4DC;
  --candy-orange:#FFA94D;
  --candy-cyan:#9EF0E0;
  --candy-blue:#B3D4FF;
  --tint-yellow:#FFF1B8;
  --tint-cyan:#D9F7F0;
  --on-dark:#FFFFFF;
  --on-dark-muted:rgb(255 255 255 / .72);
  --on-dark-line:rgb(255 255 255 / .28);
  --flag-red:#D8232F;
  --flag-navy:#24357F;
  --flag-white:#FFFFFF;
  --bar-bg:rgb(250 251 253 / .86);
  --wash-top:rgb(18 112 227 / .06);
  --wash-mid:rgb(124 196 255 / .035);
  --wash-end:rgb(250 251 253 / 0);
  --glow:rgb(124 196 255 / .34);
  --glow-fade:rgb(179 212 255 / .14);
  --glow-clear:rgb(250 251 253 / 0);
  --veil:rgb(34 38 44 / .32);
  --shadow-tray:0 44px 88px -30px rgb(18 112 227 / .10),0 14px 32px -14px rgb(18 112 227 / .10);
  --shadow-win:0 22px 44px -24px rgb(18 112 227 / .18);
  --shadow-float:0 18px 36px -8px rgb(18 112 227 / .04),0 4px 10px rgb(18 112 227 / .04);
  --inset-groove:inset 0 1px 2px rgb(34 38 44 / .08);
  --font-display:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Microsoft YaHei","Apple SD Gothic Neo","Malgun Gothic",system-ui,sans-serif;
  --font-body:"Inter","Noto Sans SC","PingFang SC","Hiragino Sans","Microsoft YaHei","Apple SD Gothic Neo","Malgun Gothic",system-ui,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",Menlo,Consolas,monospace;
  --r-btn:2px;
  --r-card:4px;
  --r-pill:999px;
  --r-circle:50%;
  --gutter:24px;
  --wrap-max:1248px;
  --header-height:64px;
  --anchor-offset:80px;
  --toc-offset:144px;
  --font-xs:12px;
  --font-sm:14px;
  --font-base:16px;
  --font-lead:20px;
  --h1-size:clamp(52px,5vw,66px);
  --h2-size:clamp(28px,3.2vw,40px);
  --h3-size:24px;
  --weight-light:300;
  --weight-normal:400;
  --weight-medium:500;
  --weight-semibold:600;
  --weight-bold:700;
  --weight-brand:800;
  --weight-heavy:900;
  --tracking-title:-.02em;
  --tracking-brand:-.01em;
  --tracking-button:.01em;
  --ease-ui:cubic-bezier(.2,.7,.2,1);
  --duration-ui:.2s;
  --duration-reveal:.35s;
}
* {box-sizing:border-box;margin:0;padding:0}
html {-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:var(--anchor-offset)}
body {background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:var(--font-base);line-height:1.6;-webkit-font-smoothing:antialiased}
html.nav-open {overflow:hidden}
[hidden] {display:none!important}
img,video {display:block;max-width:100%;height:auto}
svg {flex-shrink:0;max-width:100%}
a {color:inherit;text-decoration:none}
button,input,select,textarea {font:inherit;color:inherit}
button {cursor:pointer}
button:disabled {cursor:not-allowed}
button {background:var(--bg-panel);border:1px solid var(--border)}
:where(a,button,summary,input,textarea,select,[tabindex]):focus-visible {outline:2px solid var(--accent);outline-offset:3px}
h1,h2,h3 {font-family:var(--font-display);text-wrap:balance;overflow-wrap:break-word}
h1 {font-size:var(--h1-size);line-height:1.12;font-weight:var(--weight-light);letter-spacing:var(--tracking-title)}
h2 {font-size:var(--h2-size);line-height:1.25;font-weight:var(--weight-normal);letter-spacing:var(--tracking-title)}
h3 {font-size:var(--h3-size);line-height:1.35;font-weight:var(--weight-semibold)}
p {overflow-wrap:break-word}
code {font-family:var(--font-mono);overflow-wrap:anywhere}
pre {max-width:100%;overflow-x:auto;padding:20px;background:var(--groove);border:1px solid var(--border);font-family:var(--font-mono);font-size:var(--font-sm)}
pre code {overflow-wrap:normal;white-space:pre}
ul,ol {padding-left:1.5em}
.no-break {white-space:nowrap}
.wrap {width:100%;max-width:var(--wrap-max);margin-inline:auto;padding-inline:var(--gutter);min-width:0}
.section {padding-top:64px;padding-bottom:64px}
.section-head {max-width:800px;margin-bottom:32px}
.section-head p {margin-top:16px;color:var(--text-muted)}
.stack > * + * {margin-top:20px}
.muted {color:var(--text-muted)}
.mono {font-family:var(--font-mono)}
.accent {color:var(--accent);font-weight:var(--weight-heavy)}
.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}
:where(.grid-three,.grid-five,.panel,.card) > * {min-width:0}
.panel,.card {min-width:0;background:var(--bg-panel);border:1px solid var(--ink);border-radius:var(--r-card)}
.panel-body,.card-body {padding:24px}
.panel-bar {display:flex;align-items:center;justify-content:flex-end;gap:16px;padding:14px 24px;background:linear-gradient(90deg,var(--ink),var(--ink-2));color:var(--on-dark)}
.panel-bar a {display:inline-flex;align-items:center;min-height:28px;font-weight:var(--weight-semibold)}
.btn {display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:10px 32px;border:1.5px solid var(--ink);border-radius:var(--r-btn);font-size:var(--font-base);font-weight:var(--weight-semibold);letter-spacing:var(--tracking-button);transition:background var(--duration-ui),color var(--duration-ui);text-align:center}
.btn-solid,.btn-primary {background:var(--ink);color:var(--on-dark)}
.btn-solid:hover,.btn-primary:hover {background:var(--ink-2)}
.btn-line,.btn-secondary {background:var(--bg-panel);color:var(--ink)}
.btn-line:hover,.btn-secondary:hover {background:var(--bg-panel2)}
.btn-small {min-height:38px;padding:6px 18px;font-size:var(--font-sm)}
.btn:disabled,.btn[aria-disabled="true"] {opacity:.5;pointer-events:none}
.cta-row {margin-top:24px;display:flex;gap:12px;justify-content:center}
.topbar {position:relative;z-index:50;height:var(--header-height);background:var(--bar-bg);border-bottom:1px solid var(--border);backdrop-filter:blur(10px)}
.topbar .wrap {display:flex;align-items:center;flex-wrap:nowrap;height:100%;gap:40px}
.brand {display:flex;align-items:center;gap:10px;flex:none;min-height:30px}
.brand-mark {width:30px;height:30px;display:block;flex:none}
.brand-en {font-family:var(--font-display);font-weight:var(--weight-brand);font-size:19px;letter-spacing:var(--tracking-brand);color:var(--text)}
.brand-zh {font-size:var(--font-sm);font-weight:var(--weight-normal);color:var(--text-muted);padding-left:10px;border-left:1px solid var(--border);line-height:1}
.mainnav {flex:1;min-width:0}
.mainnav ul {display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:2px}
.mainnav a {display:block;padding:7px 14px;border-radius:var(--r-pill);font-size:15px;color:var(--nav-idle);white-space:nowrap;transition:color var(--duration-ui)}
.mainnav a:hover {color:var(--text)}
.mainnav a[aria-current="page"] {background:var(--accent-soft);color:var(--accent-dark);font-weight:var(--weight-semibold)}
.topbar-end {margin-left:auto;display:flex;align-items:center;gap:20px;flex-shrink:0}
.lang-picker {position:relative}
.lang {display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:32px;min-width:32px;width:auto;padding:4px 0;border:0;background:var(--wash-end);font-size:var(--font-sm);color:var(--text-muted);white-space:nowrap}
.lang svg {width:16px;height:16px;flex:none}
.lang .ln {fill:none;stroke:currentColor;stroke-width:1.5}
.lang-panel {position:absolute;z-index:80;right:0;top:calc(100% + 12px);min-width:180px;padding:8px;background:var(--bg-panel);border:1px solid var(--ink);box-shadow:var(--shadow-win);border-radius:var(--r-card)}
.lang-panel a {display:flex;align-items:center;min-height:44px;padding:8px 12px;border-radius:var(--r-btn)}
.lang-panel a:hover,.lang-panel a[aria-current="true"] {background:var(--accent-soft);color:var(--accent-dark)}
.btn-login {display:inline-flex;align-items:center;justify-content:center;flex-shrink:0;height:38px;padding:0 20px;border:1.5px solid var(--ink);border-radius:var(--r-btn);background:var(--bg-panel);color:var(--ink);font-size:var(--font-sm);font-weight:var(--weight-semibold);white-space:nowrap}
.btn-login:hover {background:var(--ink);color:var(--on-dark)}
.menu-toggle {display:none;align-items:center;justify-content:center;flex-direction:column;gap:4px;min-width:44px;min-height:44px;border:0;background:var(--wash-end)}
.menu-line {display:block;width:20px;height:2px;background:currentColor;border-radius:var(--r-btn)}
.mobile-drawer {position:fixed;z-index:45;top:var(--header-height);left:0;right:0;height:calc(100dvh - var(--header-height));max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;background:var(--bg-panel);padding:16px var(--gutter) 32px;border-top:1px solid var(--border)}
.mobile-drawer ul {list-style:none;margin:0;padding:0}
.mobile-drawer a {display:flex;align-items:center;width:100%;min-height:48px;padding:12px 16px;border-radius:var(--r-card)}
.mobile-drawer a:hover,.mobile-drawer a[aria-current] {background:var(--accent-soft);color:var(--accent-dark)}
.drawer-languages {margin-top:20px;padding-top:16px;border-top:1px solid var(--border)}
.nav-veil {position:fixed;z-index:40;inset:var(--header-height) 0 0;background:var(--veil);border:0}
.site-footer {padding-top:48px;padding-bottom:24px;background:var(--bg-panel2);border-top:1px solid var(--border)}
.footer-grid {display:grid;grid-template-columns:1.3fr 1fr 1fr;gap:48px}
.footer-brand p {max-width:360px;margin-top:16px;color:var(--text-muted);font-size:var(--font-sm)}
.footer-heading {font-size:var(--font-base);font-weight:var(--weight-semibold);margin-bottom:12px}
.footer-links {list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:4px 16px}
.footer-links a,.footer-languages a,.footer-legal a {display:inline-flex;align-items:center;min-height:28px;padding-block:2px;font-size:var(--font-sm);color:var(--text-muted)}
.footer-links a:hover,.footer-languages a:hover,.footer-legal a:hover {color:var(--accent-dark)}
.footer-languages {display:flex;flex-wrap:wrap;gap:8px 20px;margin-top:32px;padding-top:20px;border-top:1px solid var(--border)}
.footer-bottom {display:flex;justify-content:space-between;flex-wrap:wrap;gap:12px;margin-top:20px;font-size:var(--font-xs);color:var(--text-muted)}
.footer-legal {display:flex;flex-wrap:wrap;gap:16px}
.prose {min-width:0;max-width:880px}
.prose p,.prose ul,.prose ol {margin-block:18px}
.prose h2 {margin-top:48px;margin-bottom:20px}
.prose h3 {margin-top:28px;margin-bottom:14px}
.prose a:not(.btn) {color:var(--accent-dark);text-decoration:underline;text-underline-offset:3px}
.prose li + li {margin-top:8px}
.prose section[id] {scroll-margin-top:var(--anchor-offset)}
.reveal {transition:opacity var(--duration-reveal) var(--ease-ui),transform var(--duration-reveal) var(--ease-ui)}
.reveal.pending {opacity:0;transform:translateY(16px)}
.reveal.shown {opacity:1;transform:none}
[data-counter] {display:inline-block;min-width:3ch;text-align:right;font-variant-numeric:tabular-nums;font-family:var(--font-mono)}
[data-counter="7"] {min-width:1ch}
#server-status {position:static;display:block;min-height:160px;min-width:0;max-width:100%;overflow:hidden;margin-top:24px;margin-bottom:24px}
#server-status + * {margin-top:24px}
@media (max-width:1180px) {
  .topbar .wrap {gap:24px}
  .mainnav a {padding:7px 10px;font-size:var(--font-sm)}
  .brand-zh {display:none}
}
@media (max-width:1080px) {
  .mainnav {display:none}
  .topbar .wrap {gap:16px}
  .topbar-end {margin-left:auto;gap:12px}
  .menu-toggle {display:inline-flex}
}
@media (min-width:1081px) {
  .mobile-drawer,.nav-veil {display:none!important}
}
@media (max-width:768px) {
  :root {--gutter:16px;--h1-size:38px;--h2-size:30px;--h3-size:22px}
  .section {padding-top:40px;padding-bottom:40px}
  .grid-three {grid-template-columns:minmax(0,1fr)}
  .grid-five {grid-template-columns:repeat(2,minmax(0,1fr))}
  .footer-grid {grid-template-columns:minmax(0,1fr);gap:28px}
  .footer-brand p {max-width:none}
  .topbar-end {margin-left:auto}
}
@media (max-width:640px) {
  .no-break {white-space:normal}
  .lang span {display:none}
  .topbar .wrap {gap:8px}
  .topbar-end {gap:8px;margin-left:auto}
  .brand-en {font-size:17px}
  .brand {gap:7px}
  .btn-login {padding-inline:12px}
  .cta-row {flex-direction:column;width:100%;max-width:360px}
  .cta-row .btn {width:100%}
  .tilt,[data-tilt] {transform:none}
  .panel-body,.card-body {padding:20px}
}
@media (prefers-reduced-motion:reduce) {
  html {scroll-behavior:auto}
  .reveal,.reveal.pending {opacity:1;transform:none;transition:none}
  .btn,.mainnav a {transition:none}
}