:root {
  --bg: #FFFFFF;
  --bg-soft: #FBFAF8;
  --bg-panel: #F6F4F1;
  --bg-panel-2: #EFECE7;
  --border: #E7E2DB;
  --border-strong: #D9D2C8;
  --accent: #EF6F3C;
  --accent-dark: #C9502A;
  --apricot: #F5A25D;
  --sky: #7FA3C2;
  --text: #1F1B18;
  --text-muted: #6E655D;
  --text-faint: #9A9087;
  --success: #2FA56A;
  --warn: #D99A1E;
  --error: #E0484A;
  --font-display: "Inter", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "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;
  --r-xs: 6px;
  --r-sm: 9px;
  --r-md: 12px;
  --r-lg: 16px;
  --r-xl: 24px;
  --r-2xl: 28px;
  --r-frame: 34px;
  --r-pill: 999px;
  --grad-accent: linear-gradient(100deg, var(--accent), var(--apricot));
  --shadow-card: 0 1px 2px color-mix(in srgb, var(--text) 5%, transparent), 0 4px 12px -6px color-mix(in srgb, var(--text) 12%, transparent);
  --shadow-pop: 0 2px 4px color-mix(in srgb, var(--text) 5%, transparent), 0 18px 40px -16px color-mix(in srgb, var(--text) 22%, transparent);
  --shadow-device: 0 1px 2px color-mix(in srgb, var(--text) 7%, transparent), 0 12px 24px -12px color-mix(in srgb, var(--text) 18%, transparent), 0 46px 100px -28px color-mix(in srgb, var(--accent) 42%, transparent);
  --wrap: 1360px;
  --gutter: 56px;
  --nav-h: 76px;
}
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
html.nav-open { overflow: hidden; }
body { margin: 0; background: var(--bg); color: var(--text); font: 16px/1.6 var(--font-body); -webkit-font-smoothing: antialiased; }
a { color: inherit; text-decoration: none; }
button, input { font: inherit; }
button { cursor: pointer; }
img, svg { max-width: 100%; }
img { display: block; }
ul { margin: 0; padding: 0; list-style: none; }
h1, h2, h3, h4, p { margin: 0; }
h1, h2, h3 { font-family: var(--font-display); text-wrap: balance; }
h1 { font-weight: 800; font-size: clamp(34px, 3.35vw, 48px); line-height: 1.17; letter-spacing: -0.015em; }
h2 { font-weight: 800; font-size: clamp(26px, 2.5vw, 36px); line-height: 1.24; }
h3 { font-weight: 700; font-size: 20px; line-height: 1.35; }
p + p { margin-top: 1em; }
code, pre, .mono { font-family: var(--font-mono); }
code { overflow-wrap: anywhere; }
pre { max-width: 100%; overflow-x: auto; }
:focus-visible { outline: 2px solid var(--accent-dark); outline-offset: 3px; border-radius: var(--r-xs); }
[hidden] { display: none !important; }
.page { overflow-x: clip; }
.wrap { width: 100%; max-width: var(--wrap); margin-inline: auto; padding-inline: var(--gutter); }
.sec { padding-top: 90px; padding-bottom: 90px; }
.nowrap { white-space: nowrap; }
.grad-text { background: var(--grad-accent); background-clip: text; -webkit-background-clip: text; color: transparent; }
.muted { color: var(--text-muted); }
.panel { min-width: 0; padding: 40px; border-radius: var(--r-2xl); background: var(--bg-panel); color: var(--text); }
.card { min-width: 0; padding: 24px; border: 1px solid var(--border); border-radius: var(--r-lg); background: var(--bg); color: var(--text); box-shadow: var(--shadow-card); }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  min-height: 52px; padding: 0 26px; border: 1px solid transparent; border-radius: var(--r-pill);
  font-size: 16px; font-weight: 700; line-height: 1.3; text-align: center;
  transition: background-color .18s, border-color .18s, transform .18s, box-shadow .18s;
}
.btn svg { width: 18px; height: 18px; flex-shrink: 0; }
.btn-primary { background: var(--accent-dark); color: var(--bg); box-shadow: 0 10px 22px -10px color-mix(in srgb, var(--accent) 75%, transparent); }
.btn-primary:hover { background: var(--text); color: var(--bg); transform: translateY(-1px); }
.btn-secondary { background: var(--bg); color: var(--text); border-color: var(--border); }
.btn-secondary:hover { background: var(--bg-panel); color: var(--text); border-color: var(--border-strong); }
.btn:disabled, .btn[aria-disabled="true"] { opacity: .55; cursor: not-allowed; transform: none; }
.reveal { opacity: 0; transform: translateY(16px); transition: opacity .55s ease, transform .55s ease; }
.reveal.shown { opacity: 1; transform: none; }

/* The header uses a wider measure than article content. */
.topbar { position: relative; z-index: 30; height: var(--nav-h); background: var(--bg); color: var(--text); }
.topbar-in { max-width: min(100%, calc(1280px + var(--gutter) * 2)); height: 100%; margin-inline: auto; padding-inline: var(--gutter); display: flex; align-items: center; gap: 32px; }
.brand { display: inline-flex; align-items: center; gap: 10px; flex-shrink: 0; }
.brand img { width: 32px; height: 32px; flex-shrink: 0; }
.brand-name { font-family: var(--font-display); font-size: 17px; font-weight: 800; letter-spacing: -0.01em; }
.mainnav { min-width: 0; margin-left: auto; }
.mainnav-list { display: flex; align-items: center; gap: 6px; list-style: none; margin: 0; padding: 0; }
.mainnav-list > li { position: relative; }
.nav-link, .nav-more-btn {
  display: inline-flex; align-items: center; justify-content: center; min-height: 40px; padding: 0 15px;
  border: 0; border-radius: var(--r-pill); background: transparent; color: var(--text-muted);
  font-size: 15px; font-weight: 500; white-space: nowrap;
}
.nav-link:hover, .nav-more-btn:hover { background: var(--bg-panel); color: var(--text); }
.nav-link[aria-current="page"] { position: relative; color: var(--text); font-weight: 700; }
.nav-link[aria-current="page"]::after { content: ""; position: absolute; bottom: 3px; left: calc(50% - 2px); width: 4px; height: 4px; border-radius: var(--r-pill); background: var(--accent); }
.nav-more-btn svg { width: 14px; height: 14px; margin-left: 4px; }
.nav-more[aria-expanded="true"] .nav-menu, .nav-more:hover .nav-menu, .nav-more:focus-within .nav-menu { opacity: 1; visibility: visible; transform: none; }
.nav-menu {
  position: absolute; top: calc(100% + 8px); left: 50%; width: 240px; margin-left: -120px; padding: 8px;
  border: 1px solid var(--border); border-radius: var(--r-lg); background: var(--bg); color: var(--text);
  box-shadow: var(--shadow-pop); opacity: 0; visibility: hidden; transform: translateY(4px);
  transition: opacity .18s, transform .18s, visibility .18s;
}
.nav-menu-label { padding: 6px 12px 4px; color: var(--text-muted); font-size: 12px; }
.nav-menu a { display: flex; flex-direction: column; justify-content: center; min-height: 48px; padding: 7px 12px; border-radius: var(--r-sm); }
.nav-menu a:hover { background: var(--bg-panel); color: var(--text); }
.menu-t { font-size: 14px; font-weight: 700; }
.menu-d { color: var(--text-muted); font-size: 12px; }
.header-tools { position: relative; display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.lang-btn { display: inline-flex; align-items: center; justify-content: center; gap: 7px; min-height: 40px; padding: 0 16px; border: 1px solid var(--border); border-radius: var(--r-pill); background: var(--bg); color: var(--text); font-size: 14px; white-space: nowrap; }
.lang-btn:hover { border-color: var(--border-strong); }
.lang-btn svg { width: 15px; height: 15px; flex-shrink: 0; }
.lang-short { display: none; }
.lang-menu { position: absolute; top: calc(100% + 8px); right: 0; width: 190px; padding: 7px; border: 1px solid var(--border); border-radius: var(--r-lg); background: var(--bg); color: var(--text); box-shadow: var(--shadow-pop); }
.lang-menu a { display: flex; align-items: center; min-height: 44px; padding: 8px 12px; border-radius: var(--r-sm); }
.lang-menu a:hover, .lang-menu a[aria-current="page"] { background: var(--bg-panel); color: var(--text); }
.menu-toggle { display: none; align-items: center; justify-content: center; width: 44px; min-width: 44px; height: 44px; border: 1px solid var(--border); border-radius: var(--r-md); background: var(--bg); color: var(--text); }
.menu-toggle svg { width: 22px; height: 22px; }
.mobile-nav { display: none; }
.nav-veil { display: none; }

.site-footer { border-top: 1px solid var(--border); background: var(--bg-panel); color: var(--text); }
.footer-grid { display: grid; grid-template-columns: 1.35fr 1fr 1.25fr .8fr; gap: 40px; padding-top: 64px; padding-bottom: 54px; }
.footer-brand p { max-width: 30em; margin-top: 18px; color: var(--text-muted); font-size: 14px; }
.footer-col h2 { margin-bottom: 14px; color: var(--text); font-size: 14px; }
.footer-col ul { display: grid; gap: 9px; }
.footer-col a { color: var(--text-muted); font-size: 14px; overflow-wrap: anywhere; }
.footer-col a:hover { color: var(--accent-dark); }
.footer-bottom { display: flex; justify-content: space-between; gap: 16px; padding-top: 20px; padding-bottom: 28px; border-top: 1px solid var(--border); color: var(--text-muted); font-size: 13px; }
.footer-bottom a:hover { color: var(--accent-dark); }

@media (max-width: 1240px) { :root { --gutter: 40px; } .topbar-in { gap: 16px; } .mainnav-list { gap: 0; } .nav-link, .nav-more-btn { padding-inline: 11px; } }
@media (max-width: 900px) {
  :root { --gutter: 24px; --nav-h: 68px; }
  .mainnav { display: none; }
  .header-tools { margin-left: auto; }
  .menu-toggle { display: inline-flex; }
  .mobile-nav {
    display: block; position: absolute; z-index: 21; top: 100%; left: 0; right: 0; max-height: calc(100dvh - var(--nav-h));
    padding: 12px var(--gutter) 24px; overflow-y: auto; overscroll-behavior: contain;
    border-top: 1px solid var(--border); background: var(--bg); color: var(--text); box-shadow: var(--shadow-pop);
  }
  .mobile-nav[hidden] { display: none; }
  .mobile-nav ul { display: grid; gap: 3px; }
  .mobile-nav a { display: flex; align-items: center; width: 100%; min-height: 48px; padding: 10px 14px; border-radius: var(--r-md); font-weight: 600; }
  .mobile-nav a:hover, .mobile-nav a[aria-current="page"] { background: var(--bg-panel); color: var(--text); }
  .mobile-nav-label { padding: 18px 14px 5px; color: var(--text-muted); font-size: 12px; }
  .nav-veil.is-open { display: block; position: fixed; inset: var(--nav-h) 0 0; z-index: 20; border: 0; background: color-mix(in srgb, var(--text) 30%, transparent); }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 640px) {
  :root { --gutter: 18px; --nav-h: 64px; }
  h1 { font-size: clamp(24px, 7vw, 30px); }
  h2 { font-size: 26px; }
  .sec { padding-top: 62px; padding-bottom: 62px; }
  .panel { padding: 24px; }
  .brand { min-width: 0; flex-shrink: 1; }
  .brand-name { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 15px; }
  .brand img { width: 28px; height: 28px; }
  .lang-full { display: none; }
  .lang-short { display: inline; }
  .lang-btn { padding-inline: 12px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 30px 18px; }
  .footer-brand { grid-column: 1 / -1; }
  .footer-bottom { flex-wrap: wrap; }
  .tilt, .device { transform: none !important; }
}
@media (max-width: 360px) { :root { --gutter: 16px; } .topbar-in { gap: 8px; } .brand-name { font-size: 13px; } }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal { opacity: 1; transform: none; }
}