:root {
  --bg: #F1F7FD;
  --bg-panel: #FFFFFF;
  --bg-panel-2: #E5EFF9;
  --border: #D5E1EC;
  --border-strong: #C2D1DF;
  --accent: #E4572E;
  --accent-dark: #B8401F;
  --text: #0D1321;
  --text-muted: #5A6678;
  --text-dim: #7C8798;
  --success: #1F9D6B;
  --warn: #C98A12;
  --error: #D2343F;
  --tint-sky: #CFE6F8;
  --tint-orchid: #F5DDF0;
  --tint-apricot: #FADCCB;
  --beam-cyan: #2BA9D8;
  --beam-orchid: #B76BD6;
  --ink: #0D1321;
  --ink-hover: #243047;
  --on-ink: #FFFFFF;
  --btn-ghost: #E3EAF2;
  --btn-ghost-hover: #D7E1EB;
  --success-ring: rgba(31, 157, 107, 0.16);
  --glow-ice: rgba(190, 222, 247, 0.78);
  --glow-white: rgba(255, 255, 255, 0.9);
  --band-glass: rgba(255, 255, 255, 0.55);
  --veil: rgba(13, 19, 33, 0.22);
  --shadow-float: 0 1px 2px rgba(13, 19, 33, 0.04), 0 10px 28px -18px rgba(13, 19, 33, 0.18);
  --device-cyan-hi: #A9E2F4;
  --device-cyan-side: #17698C;
  --device-orchid-hi: #F5CBEB;
  --device-orchid-side: #8C47AE;
  --device-sky-hi: #F8FCFF;
  --device-sky: #B5DAF4;
  --device-sky-side: #8CC0E5;
  --device-coral-hi: #F7A47F;
  --device-coral-side: #93321A;
  --code-key: #A9E2F4;
  --code-value: #F5CBEB;
  --code-comment: #B5C4D5;
  --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;
  --radius: 6px;
  --radius-sm: 4px;
  --radius-round: 50%;
  --gutter: clamp(20px, 3.9vw, 56px);
  --wrap-max: 1440px;
  --read-max: 820px;
  --space-section: 96px;
  --motion-fast: 180ms;
  --motion-reveal: 550ms;
}
*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 32px;
}
html.nav-open { overflow: hidden; }
body {
  margin: 0;
  background: var(--bg-panel);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
[hidden] { display: none !important; }
a { color: inherit; text-decoration: none; }
a:hover { color: var(--accent-dark); }
img, svg { max-width: 100%; vertical-align: middle; }
img { height: auto; }
button, input, select, textarea { font: inherit; }
button, a, summary { -webkit-tap-highlight-color: var(--success-ring); }
button { cursor: pointer; }
button:disabled { cursor: not-allowed; }
button, input, select, textarea { max-width: 100%; }
:focus-visible {
  outline: 2px solid var(--accent-dark);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}
::selection { background: var(--tint-sky); color: var(--text); }
h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--text);
  line-height: 1.25;
  text-wrap: balance;
  overflow-wrap: break-word;
}
h1 { font-size: clamp(34px, 3.4vw, 48px); font-weight: 800; letter-spacing: -0.02em; }
h2 { font-size: clamp(24px, 2.4vw, 34px); font-weight: 800; letter-spacing: -0.02em; }
h3 { font-size: 22px; font-weight: 700; }
p { margin: 0 0 1.25em; }
ul, ol { padding-left: 1.4em; }
dl, dd { margin: 0; }
code, pre, kbd { font-family: var(--font-mono); }
code { overflow-wrap: anywhere; font-size: 0.88em; }
pre {
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  padding: 24px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-panel-2);
  color: var(--text);
  line-height: 1.8;
  tab-size: 2;
}
pre code { white-space: pre; overflow-wrap: normal; word-break: normal; }
hr { border: 0; border-top: 1px solid var(--border); margin-block: 32px; }
.wrap {
  width: 100%;
  max-width: var(--wrap-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.reading { max-width: var(--read-max); margin-inline: auto; min-width: 0; }
.section { padding-top: var(--space-section); padding-bottom: var(--space-section); }
.section-soft { background: var(--bg); color: var(--text); }
.grid { display: grid; gap: 24px; }
.grid-two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid > *, .hero-grid > *, .topbar-inner > *, .footer-grid > *, .feature-panel > * { min-width: 0; }
.mono { font-family: var(--font-mono); font-weight: 500; }
.muted { color: var(--text-muted); }
.keep { white-space: nowrap; }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}
.skip-link {
  position: fixed;
  z-index: 100;
  top: 12px;
  left: var(--gutter);
  padding: 12px 18px;
  transform: translateY(-160%);
  background: var(--ink);
  color: var(--on-ink);
  border-radius: var(--radius);
}
.skip-link:focus { transform: none; color: var(--on-ink); }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 48px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 13.5px;
  font-weight: 600;
  letter-spacing: 0.08em;
  line-height: 1.6;
  text-transform: uppercase;
  text-align: center;
  transition: background-color var(--motion-fast), color var(--motion-fast), border-color var(--motion-fast);
}
.btn svg { width: 15px; height: 15px; flex-shrink: 0; }
.btn-primary { background: var(--ink); color: var(--on-ink); }
.btn-primary:hover, .btn-primary.is-hover { background: var(--ink-hover); color: var(--on-ink); }
.btn-primary:active { background: var(--text-muted); color: var(--on-ink); }
.btn-ghost { background: var(--btn-ghost); color: var(--text); }
.btn-ghost:hover, .btn-ghost.is-hover { background: var(--btn-ghost-hover); color: var(--accent-dark); }
.btn-outline { background: var(--bg-panel); color: var(--text); border-color: var(--border-strong); }
.btn-outline:hover { background: var(--bg); color: var(--accent-dark); border-color: var(--accent-dark); }
.btn:disabled, .btn[aria-disabled="true"] { background: var(--bg-panel-2); color: var(--text-muted); border-color: var(--border); }
.btn[aria-disabled="true"] { pointer-events: none; }
.btn.is-focus { outline: 2px solid var(--accent-dark); outline-offset: 3px; }
.card, .panel {
  min-width: 0;
  padding: 28px;
  background: var(--bg-panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.card h3 { margin-top: 0; }
.panel-sky { background: var(--tint-sky); color: var(--text); }
.panel-orchid { background: var(--tint-orchid); color: var(--text); }
.panel-apricot { background: var(--tint-apricot); color: var(--text); }
.prose { min-width: 0; }
.prose h2 { margin-top: 2.3em; margin-bottom: 0.8em; scroll-margin-top: 32px; }
.prose h3 { margin-top: 1.8em; }
.prose p, .prose li { color: var(--text-muted); }
.prose strong { color: var(--text); }
.prose a { color: var(--accent-dark); text-decoration: underline; text-underline-offset: 3px; }
.prose li + li { margin-top: 8px; }
.prose :not(pre) > code {
  background: var(--bg-panel-2);
  color: var(--text);
  border-radius: var(--radius-sm);
  padding: 2px 5px;
}
.reveal { opacity: 1; transform: none; }
.reveal-ready .reveal:not(.shown) { opacity: 0; transform: translateY(16px); }
.reveal-ready .reveal {
  transition: opacity var(--motion-reveal) ease, transform var(--motion-reveal) ease;
}
.reveal.shown { opacity: 1; transform: none; }

/* 独立的宽页头；品牌、桌面导航、工具区、抽屉为同级。 */
.topbar, #site-header { position: relative; z-index: 40; padding-top: 16px; }
.topbar-inner {
  position: relative;
  display: flex;
  align-items: center;
  gap: 24px;
  width: 100%;
  max-width: min(100%, calc(1280px + var(--gutter) * 2));
  margin-inline: auto;
  padding-inline: var(--gutter);
  min-height: 60px;
}
.topbar-inner::before {
  content: "";
  position: absolute;
  inset: 0 calc(var(--gutter) + 152px) 0 var(--gutter);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-panel);
  color: var(--text);
  box-shadow: var(--shadow-float);
  z-index: -1;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
  padding-left: 16px;
  font: 700 17px/1.4 var(--font-display);
  letter-spacing: -0.01em;
  color: var(--text);
}
.brand img { width: 30px; height: 30px; flex-shrink: 0; }
.desktop-nav { margin-left: auto; min-width: 0; }
.nav-list {
  display: flex;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 0;
}
.nav-list li { display: flex; align-items: center; white-space: nowrap; }
.nav-list li + li::before { content: "·"; color: var(--text-muted); margin-inline: 14px; }
.nav-list a { color: var(--text-muted); font-size: 14.5px; }
.nav-list a:hover { color: var(--accent-dark); }
.nav-list a[aria-current="page"] {
  color: var(--text);
  font-weight: 600;
  text-decoration: underline;
  text-decoration-color: var(--accent);
  text-decoration-thickness: 1.5px;
  text-underline-offset: 7px;
}
.header-tools {
  position: relative;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  min-width: 142px;
  height: 60px;
  margin-left: 22px;
  padding-inline: 6px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-panel);
  color: var(--text);
  box-shadow: var(--shadow-float);
}
.lang, .menu-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding-inline: 12px;
  border: 0;
  border-radius: var(--radius);
  background: var(--bg-panel);
  color: var(--text);
  font-size: 14px;
}
.lang:hover, .menu-toggle:hover { background: var(--bg-panel-2); color: var(--text); }
.lang svg { width: 15px; height: 15px; flex-shrink: 0; }
.lang-short { display: none; }
.lang-caret { color: var(--text-muted); font-size: 12px; }
.lang-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  width: 190px;
  max-width: calc(100vw - var(--gutter) * 2);
  padding: 6px;
  list-style: none;
  margin: 0;
  background: var(--bg-panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-float);
}
.lang-menu a { display: flex; align-items: center; min-height: 44px; padding: 10px 14px; }
.lang-menu a:hover, .lang-menu a[aria-current] { background: var(--bg-panel-2); color: var(--text); }
.menu-toggle { display: none; min-width: 44px; }
.menu-toggle svg { width: 20px; height: 20px; }
.mobile-drawer, .menu-veil { display: none; }
.site-footer {
  background: var(--bg);
  color: var(--text);
  border-top: 1px solid var(--border);
  padding-top: 64px;
  padding-bottom: 28px;
}
.footer-grid { display: grid; grid-template-columns: 1.2fr 0.8fr 1.4fr 0.7fr; gap: 40px; }
.site-footer .brand { padding-left: 0; }
.footer-intro { margin-top: 20px; max-width: 25em; color: var(--text-muted); font-size: 14px; }
.footer-heading { margin: 0 0 16px; font-size: 14px; font-weight: 700; }
.footer-links { list-style: none; padding: 0; margin: 0; display: grid; gap: 9px; }
.footer-links a { font-size: 14px; color: var(--text-muted); overflow-wrap: anywhere; }
.footer-links a:hover { color: var(--accent-dark); }
.copyright {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
  border-top: 1px solid var(--border);
  margin-top: 40px;
  padding-top: 22px;
  font-size: 12px;
  color: var(--text-muted);
}
.copyright p { margin: 0; }

/* 拍板首屏：冰蓝渐白、46/54 分栏、双色标题、独立平台行。 */
.first-screen {
  position: relative;
  isolation: isolate;
  overflow-x: clip;
  display: grid;
  grid-template-rows: auto 1fr auto;
  min-height: calc(100svh - 44px);
  background: linear-gradient(180deg, var(--bg) 0%, var(--bg) 74%, var(--bg-panel) 100%);
  color: var(--text);
}
.first-screen::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background: radial-gradient(58% 52% at 20% 42%, var(--glow-white), transparent 72%);
  color: var(--text);
  pointer-events: none;
}
.hero { display: grid; align-content: center; padding-top: 12px; padding-bottom: 8px; }
.hero-grid { display: grid; grid-template-columns: 46fr 54fr; gap: 32px; align-items: center; }
.hero-copy { position: relative; z-index: 1; display: flex; flex-direction: column; align-items: flex-start; }
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  padding: 6px 14px 6px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-panel);
  color: var(--text-muted);
  font-size: 13px;
  line-height: 1.4;
}
.hero-badge b { color: var(--text); font-size: 12.5px; }
.badge-dot { width: 8px; height: 8px; flex-shrink: 0; border-radius: var(--radius-round); background: var(--success); color: var(--text); box-shadow: 0 0 0 4px var(--success-ring); }
.hero h1 {
  margin: 24px 0 0;
  font-weight: 800;
  font-size: clamp(28px, calc(3.2vw + 2px), 48px);
  line-height: 1.14;
  letter-spacing: -0.02em;
}
.h1-line { display: block; }
.h1-sub { color: var(--text-dim); }
.hero-desc { margin: 22px 0 0; max-width: 31em; font-size: 17px; line-height: 1.72; color: var(--text-muted); }
.hero-desc strong { color: var(--text); font-weight: 600; }
.hero-chips { display: flex; flex-wrap: wrap; gap: 8px; list-style: none; padding: 0; margin: 18px 0 0; }
.hero-chips li {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 28px;
  padding: 3px 11px 3px 8px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--band-glass);
  color: var(--text-muted);
  font-size: 12.5px;
}
.hero-chips svg { width: 14px; height: 14px; color: var(--success); flex-shrink: 0; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }
.platforms { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 26px; }
.plat {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 36px;
  padding: 6px 13px 6px 11px;
  background: var(--bg-panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 13.5px;
  font-weight: 500;
}
.plat svg { width: 15px; height: 15px; flex-shrink: 0; }
.plat:hover { color: var(--accent-dark); border-color: var(--accent); }
.hero-visual { position: relative; min-width: 0; }
.hero-visual::before {
  content: "";
  position: absolute;
  inset: 32% -8% -6% 28%;
  background: radial-gradient(closest-side, var(--glow-ice), transparent 74%);
  color: var(--text);
  pointer-events: none;
}
.rule-tower { position: relative; display: block; width: 100%; height: auto; max-height: calc(100svh - 236px); margin-inline: auto; }
.tower-top-cyan { fill: url(#wafer-cyan); stroke: var(--bg-panel); stroke-width: 1; }
.tower-side-cyan { fill: var(--device-cyan-side); }
.tower-top-orchid { fill: url(#wafer-orchid); stroke: var(--bg-panel); stroke-width: 1; }
.tower-side-orchid { fill: var(--device-orchid-side); }
.tower-top-sky { fill: url(#wafer-sky); stroke: var(--bg-panel); stroke-width: 1; fill-opacity: 0.86; }
.tower-side-sky { fill: var(--device-sky-side); }
.tower-top-coral { fill: url(#wafer-coral); stroke: var(--bg-panel); stroke-width: 1; }
.tower-side-coral { fill: var(--device-coral-side); }
.stop-cyan-hi { stop-color: var(--device-cyan-hi); }
.stop-cyan { stop-color: var(--beam-cyan); }
.stop-orchid-hi { stop-color: var(--device-orchid-hi); }
.stop-orchid { stop-color: var(--beam-orchid); }
.stop-sky-hi { stop-color: var(--device-sky-hi); }
.stop-sky { stop-color: var(--device-sky); }
.stop-coral-hi { stop-color: var(--device-coral-hi); }
.stop-coral { stop-color: var(--accent); }
.tower-etch { fill: none; stroke: var(--bg-panel); stroke-width: 2; opacity: 0.6; stroke-linecap: round; }
.tower-groove { stroke: var(--device-coral-side); stroke-width: 2; stroke-linecap: round; }
.tower-label { font: 500 11px var(--font-mono); letter-spacing: 0.14em; fill: var(--ink); }
.tower-engrave { font: 600 11px var(--font-mono); letter-spacing: 0.13em; fill: var(--ink); }
.tower-annotation { fill: none; stroke: var(--ink); stroke-width: 1; opacity: 0.5; }
.tower-square { fill: var(--ink); }
.tower-beam-halo { fill: none; stroke: var(--beam-cyan); stroke-width: 11; opacity: 0.16; stroke-linecap: round; }
.tower-beam { fill: none; stroke: var(--accent); stroke-width: 1.7; stroke-linecap: round; }
.tower-node { fill: var(--bg-panel); stroke: var(--accent); stroke-width: 1.6; }
.factband { border-top: 1px solid var(--border); background: var(--band-glass); color: var(--text); }
.factband-inner { display: flex; align-items: center; gap: 28px; min-height: 60px; }
.fact-title { flex-shrink: 0; font: 600 11px var(--font-mono); letter-spacing: 0.16em; }
.facts { flex: 1; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); }
.fact { display: flex; align-items: baseline; gap: 12px; padding-inline: 24px; border-left: 1px solid var(--border); }
.fact dt { font: 400 11px var(--font-mono); letter-spacing: 0.14em; color: var(--text-muted); }
.fact dd { font: 500 14px var(--font-mono); }
.features { background: var(--bg-panel); color: var(--text); padding-top: 18px; padding-bottom: 96px; }
.eyebrow { display: flex; justify-content: center; align-items: center; gap: 10px; margin: 0; font: 500 11.5px var(--font-mono); letter-spacing: 0.16em; color: var(--text-muted); }
.eyebrow::before { content: ""; width: 7px; height: 7px; background: var(--accent); color: var(--text); flex-shrink: 0; }
.section-heading { margin: 40px 0 0; text-align: center; }
.feat-lead { margin: 14px auto 0; max-width: 36em; text-align: center; font-size: 17px; color: var(--text-muted); }

@media (max-width: 1279px) {
  .desktop-nav { display: none; }
  .topbar-inner { gap: 12px; }
  .topbar-inner::before { right: calc(var(--gutter) + 196px); }
  .header-tools { margin-left: auto; min-width: 184px; }
  .menu-toggle { display: inline-flex; }
  .menu-veil:not([hidden]) { display: block; position: fixed; inset: 0; z-index: 41; border: 0; background: var(--veil); color: var(--text); }
  .nav-open .first-screen { z-index: 50; }
  .nav-open #site-header, .nav-open .topbar { z-index: 50; }
  .nav-open .topbar-inner { z-index: 52; }
  .mobile-drawer:not([hidden]) {
    display: block;
    position: absolute;
    z-index: 52;
    top: calc(100% + 10px);
    left: var(--gutter);
    right: var(--gutter);
    max-height: calc(100dvh - 110px);
    overflow-y: auto;
    overscroll-behavior: contain;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--bg-panel);
    color: var(--text);
    box-shadow: var(--shadow-float);
  }
  .mobile-drawer ul { list-style: none; margin: 0; padding: 0; }
  .mobile-drawer a { display: flex; align-items: center; width: 100%; min-height: 44px; padding: 11px 14px; }
  .mobile-drawer a:hover, .mobile-drawer a[aria-current] { background: var(--bg-panel-2); color: var(--text); }
  .drawer-label { padding: 16px 14px 8px; margin: 8px 0 0; border-top: 1px solid var(--border); color: var(--text-muted); font-size: 12px; }
}
@media (max-width: 1120px) {
  .hero-grid { grid-template-columns: minmax(0, 1fr); gap: 12px; }
  .hero { padding-top: 40px; padding-bottom: 24px; }
  .hero-visual { max-width: 640px; width: 100%; margin-inline: auto; }
  .rule-tower { max-height: none; }
  .facts { grid-template-columns: repeat(2, minmax(0, 1fr)); row-gap: 12px; }
  .factband-inner { padding-top: 14px; padding-bottom: 14px; }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 768px) {
  h1, .hero h1 { font-size: clamp(24px, 5vw, 30px); }
  .grid-three { grid-template-columns: minmax(0, 1fr); }
}
@media (max-width: 640px) {
  :root { --gutter: 20px; --space-section: 56px; }
  .topbar-inner { gap: 8px; }
  .topbar-inner::before { right: calc(var(--gutter) + 112px); }
  .brand { gap: 7px; padding-left: 10px; font-size: 14px; }
  .brand img { width: 26px; height: 26px; }
  .header-tools { min-width: 104px; padding-inline: 2px; height: 56px; gap: 0; }
  .lang { padding-inline: 8px; gap: 5px; }
  .lang svg { display: none; }
  .lang-full { display: none; }
  .lang-short { display: inline; }
  .hero-desc { font-size: 15.5px; }
  .hero-cta { gap: 8px; }
  .hero-cta .btn { padding-inline: 16px; }
  .hero-chips { flex-direction: row; }
  .platforms { gap: 6px; }
  .plat { padding-inline: 9px; font-size: 12px; }
  .factband-inner { flex-direction: column; align-items: flex-start; gap: 12px; }
  .facts { width: 100%; }
  .fact { flex-wrap: wrap; gap: 4px 8px; padding-inline: 12px; }
  .fact dd { font-size: 12px; }
  .grid-two, .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .card, .panel { padding: 22px; }
  .tilt, [data-tilt] { transform: none !important; }
  pre { padding: 18px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal-ready .reveal:not(.shown) { opacity: 1; transform: none; }
}