:root {
  --bg: #FFFFFF;
  --bg-panel: #F7F8F9;
  --bg-panel-2: #EFF1F3;
  --border: #E4E7EB;
  --accent: #2BA14A;
  --accent-dark: #1B7A36;
  --accent-deep: #166A2E;
  --text: #15181D;
  --text-muted: #5E6570;
  --success: #22995A;
  --warn: #C98A12;
  --error: #D4423A;
  --grad-a: #5866E0;
  --on-accent: #FFFFFF;
  --transparent: transparent;
  --mask-solid: #000000;
  --grad-text: linear-gradient(90deg, var(--grad-a) 0%, var(--accent) 100%);
  --grad-block: linear-gradient(125deg, var(--grad-a) 0%, var(--accent) 100%);
  --accent-wash: rgba(43,161,74,.11);
  --accent-tint: #EAF5ED;
  --accent-hair: rgba(43,161,74,.24);
  --on-dark-hair: rgba(255,255,255,.13);
  --on-grad-dot: rgba(255,255,255,.36);
  --btn-sheen: rgba(255,255,255,.14);
  --veil: rgba(21,24,29,.24);
  --shadow-ctl: 0 1px 2px rgba(21,24,29,.05);
  --shadow-near: 0 1px 2px rgba(21,24,29,.06);
  --shadow-far: 0 24px 48px rgba(21,24,29,.075);
  --shadow-win: var(--shadow-near), var(--shadow-far);
  --r-ctl: 6px;
  --r-win: 10px;
  --r-round: 50%;
  --font-display: "Inter","Noto Sans SC","PingFang SC","Microsoft YaHei",system-ui,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;
  --weight-normal: 400;
  --weight-medium: 500;
  --size-body: 16px;
  --size-small: 14px;
  --size-caption: 12px;
  --size-h1: clamp(34px, 2.4vw + 14px, 48px);
  --size-h2: 30px;
  --size-h3: 22px;
  --size-fact: 44px;
  --leading-body: 1.5;
  --leading-prose: 1.85;
  --leading-title: 1.18;
  --tracking-title: -.01em;
  --gutter: 32px;
  --wrap: 1280px;
  --reading: 1120px;
  --head-height: 64px;
  --space-section: 88px;
  --motion-fast: .15s;
  --motion-reveal: .5s;
  --ease: ease;
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
html.nav-open { overflow: hidden; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: var(--size-body);
  line-height: var(--leading-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
[hidden] { display: none !important; }
img, svg { vertical-align: middle; }
img { max-width: 100%; height: auto; }
a { color: inherit; text-underline-offset: .2em; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
button:disabled { cursor: not-allowed; }
h1, h2, h3 {
  font-family: var(--font-display);
  font-weight: var(--weight-normal);
  text-wrap: balance;
  letter-spacing: var(--tracking-title);
}
h1, .h1 { font-size: var(--size-h1); line-height: var(--leading-title); }
h2 { font-size: var(--size-h2); line-height: 1.3; }
h3 { font-size: var(--size-h3); line-height: 1.4; }
p { margin: 0 0 1em; }
strong, b { font-weight: var(--weight-medium); }
code, pre, kbd { font-family: var(--font-mono); }
code { overflow-wrap: anywhere; }
pre {
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  padding: 20px;
  border: 1px solid var(--border);
  border-radius: var(--r-ctl);
  background: var(--bg-panel);
  color: var(--text);
  font-size: var(--size-small);
  line-height: 1.7;
  tab-size: 2;
}
pre code { white-space: pre; overflow-wrap: normal; word-break: normal; }
:focus-visible { outline: 2px solid var(--accent-dark); outline-offset: 3px; }
::selection { background: var(--accent-tint); color: var(--text); }
.wrap {
  width: 100%;
  max-width: calc(var(--reading) + var(--gutter) * 2);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.wrap--wide { max-width: calc(var(--wrap) + var(--gutter) * 2); }
.section { padding-top: var(--space-section); padding-bottom: var(--space-section); }
.section--panel { background: var(--bg-panel); color: var(--text); }
.section-title { margin: 0 0 16px; }
.muted { color: var(--text-muted); }
.nowrap { white-space: nowrap; }
.prose { min-width: 0; line-height: var(--leading-prose); }
.prose h2 { margin-top: 2.4em; scroll-margin-top: 24px; }
.prose h3 { margin-top: 1.8em; scroll-margin-top: 24px; }
.prose li + li { margin-top: .5em; }
.prose a { color: var(--accent-dark); }
.prose :not(pre) > code {
  padding: .1em .3em;
  border-radius: var(--r-ctl);
  background: var(--bg-panel-2);
  color: var(--text);
  font-size: .9em;
}
.grid { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: 24px; }
.grid > *, .panel > *, .head-in > *, .footer-grid > * { min-width: 0; }
.panel, .surface-card {
  padding: 28px;
  border: 1px solid var(--border);
  border-radius: var(--r-win);
  background: var(--bg-panel);
  color: var(--text);
  box-shadow: var(--shadow-near);
}
.surface-card { background: var(--bg); color: var(--text); }
.ic {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.ic--s { width: 14px; height: 14px; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 46px;
  padding: 10px 22px;
  border: 1px solid var(--transparent);
  border-radius: var(--r-ctl);
  font-family: var(--font-body);
  font-size: 15px;
  font-weight: var(--weight-medium);
  line-height: 1.5;
  text-decoration: none;
  text-align: center;
  transition: background-color var(--motion-fast) var(--ease), border-color var(--motion-fast) var(--ease), color var(--motion-fast) var(--ease);
}
.btn .ic { width: 17px; height: 17px; stroke-width: 1.8; }
.btn--pri {
  background: var(--accent-dark);
  color: var(--on-accent);
  box-shadow: var(--shadow-near), inset 0 1px 0 var(--btn-sheen);
}
.btn--pri:hover, .btn--hover { background: var(--accent-deep); color: var(--on-accent); }
.btn--sec {
  background: var(--bg);
  color: var(--text);
  border-color: var(--border);
  box-shadow: var(--shadow-ctl);
}
.btn--sec:hover { border-color: var(--text-muted); }
.btn--sec .ic { color: var(--text-muted); }
.btn:active, .btn--pressed { box-shadow: inset 0 1px 2px var(--accent-hair); }
.btn:disabled, .btn--disabled {
  background: var(--bg-panel-2);
  color: var(--text-muted);
  border-color: var(--border);
  box-shadow: none;
}
.btn--focus { outline: 2px solid var(--accent-dark); outline-offset: 3px; }
.actions { display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: 12px; }

.site-head { position: relative; z-index: 50; background: var(--bg); color: var(--text); border-bottom: 1px solid var(--border); }
.head-in {
  position: relative;
  max-width: min(100%, calc(1280px + var(--gutter) * 2));
  height: var(--head-height);
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
  color: var(--text);
  text-decoration: none;
  font-size: var(--size-body);
  font-weight: var(--weight-medium);
  letter-spacing: -.005em;
  white-space: nowrap;
}
.logo { width: 30px; height: 30px; display: block; flex-shrink: 0; }
.nav { min-width: 0; margin-left: auto; }
.nav ul {
  display: flex;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 2px;
}
.nav a {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  height: 36px;
  padding: 0 12px;
  border-radius: var(--r-ctl);
  color: var(--text-muted);
  font-size: 14.5px;
  white-space: nowrap;
  text-decoration: none;
  transition: color var(--motion-fast) var(--ease), background-color var(--motion-fast) var(--ease);
}
.nav a:hover, .nav a[aria-current="page"] { background: var(--bg-panel); color: var(--text); }
.nav a[aria-current="page"] .ic { color: var(--accent-dark); }
.head-tools { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.lang { position: relative; display: flex; align-items: center; margin-left: 4px; padding-left: 14px; border-left: 1px solid var(--border); }
.lang-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 34px;
  padding: 6px 10px 6px 11px;
  border: 1px solid var(--border);
  border-radius: var(--r-ctl);
  background: var(--bg);
  color: var(--text);
  font-size: 13.5px;
  white-space: nowrap;
  box-shadow: var(--shadow-ctl);
}
.lang-btn .ic { color: var(--text-muted); }
.lang-short { display: none; }
.lang-menu {
  position: absolute;
  top: calc(100% + 12px);
  right: 0;
  width: 190px;
  list-style: none;
  margin: 0;
  padding: 6px;
  border: 1px solid var(--border);
  border-radius: var(--r-win);
  background: var(--bg);
  color: var(--text);
  box-shadow: var(--shadow-win);
}
.lang-menu a { display: flex; align-items: center; min-height: 44px; padding: 10px 12px; text-decoration: none; border-radius: var(--r-ctl); }
.lang-menu a:hover, .lang-menu a[aria-current] { background: var(--bg-panel); color: var(--text); }
.menu-toggle {
  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-ctl);
  background: var(--bg);
  color: var(--text);
}
.menu-toggle .ic { width: 21px; height: 21px; }
.mobile-nav {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  padding: 16px var(--gutter) 24px;
  max-height: calc(100dvh - var(--head-height));
  overflow-y: auto;
  overscroll-behavior: contain;
  background: var(--bg);
  color: var(--text);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-far);
  z-index: 2;
}
.mobile-nav ul { list-style: none; margin: 0; padding: 0; }
.mobile-nav a { display: flex; align-items: center; gap: 10px; width: 100%; min-height: 46px; padding: 12px; border-radius: var(--r-ctl); text-decoration: none; }
.mobile-nav a:hover, .mobile-nav a[aria-current] { background: var(--bg-panel); color: var(--text); }
.mobile-languages { border-top: 1px solid var(--border); margin-top: 12px; padding-top: 12px; }
.mobile-languages p { margin: 0 12px 6px; color: var(--text-muted); font-size: var(--size-small); }
.menu-veil { position: fixed; inset: var(--head-height) 0 0; z-index: 40; border: 0; background: var(--veil); color: var(--text); }

.site-footer { padding-top: 64px; padding-bottom: 24px; border-top: 1px solid var(--border); background: var(--bg-panel); color: var(--text); }
.footer-grid { display: grid; grid-template-columns: 1.25fr 1fr 1.2fr 1fr; gap: 36px; }
.footer-title { margin: 0 0 16px; font-size: var(--size-small); font-weight: var(--weight-medium); }
.footer-intro { max-width: 290px; margin-top: 16px; color: var(--text-muted); font-size: var(--size-small); line-height: 1.8; }
.footer-links { list-style: none; margin: 0; padding: 0; }
.footer-links li + li { margin-top: 10px; }
.footer-links a { color: var(--text-muted); font-size: var(--size-small); text-decoration: none; }
.footer-links a:hover { color: var(--accent-dark); text-decoration: underline; }
.footer-bottom { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; margin-top: 40px; padding-top: 20px; border-top: 1px solid var(--border); color: var(--text-muted); font-size: var(--size-caption); }
.footer-legal { display: flex; gap: 20px; }
.footer-legal a { text-decoration: none; }

.reveal { opacity: 1; transform: none; }
.reveal-pending { opacity: 0; transform: translateY(14px); transition: opacity var(--motion-reveal) var(--ease), transform var(--motion-reveal) var(--ease); }
.reveal.shown { opacity: 1; transform: none; }
.decorated, .hero { overflow-x: clip; }
@media (max-width: 1280px) {
  .nav a { padding-inline: 9px; gap: 6px; }
}
@media (max-width: 1120px) {
  .nav { display: none; }
  .menu-toggle { display: inline-flex; }
  .head-tools { margin-left: auto; }
  .head-in { gap: 12px; }
}
@media (min-width: 1121px) {
  .mobile-nav, .menu-veil { display: none !important; }
}
@media (max-width: 768px) {
  :root { --size-h1: clamp(24px, 4vw, 30px); --gutter: 24px; --space-section: 64px; }
  .grid { grid-template-columns: repeat(2,minmax(0,1fr)); }
  .footer-grid { grid-template-columns: repeat(2,minmax(0,1fr)); }
}
@media (max-width: 640px) {
  :root { --gutter: 16px; --size-h2: 24px; --size-h3: 20px; }
  .head-in { padding-inline: var(--gutter); gap: 8px; }
  .brand { gap: 8px; font-size: 14px; }
  .head-tools { margin-left: auto; gap: 6px; }
  .lang { margin-left: 0; padding-left: 0; border-left: 0; }
  .lang-long { display: none; }
  .lang-short { display: inline; }
  .lang-btn { min-height: 44px; padding-inline: 8px; }
  .lang-btn > .ic:first-child { display: none; }
  .grid, .footer-grid { grid-template-columns: minmax(0,1fr); }
  .panel, .surface-card { padding: 20px; }
  .tilt, [data-tilt] { transform: none !important; }
  .footer-grid { gap: 28px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: 0s !important; animation-duration: 0s !important; }
  .reveal-pending { opacity: 1; transform: none; }
}