:root {
  color-scheme: light;
  --ink: #10243b;
  --muted: #536880;
  --line: #d0dce8;
  --control: #6f839a;
  --surface: #fff;
  --soft: #eff6fd;
  --page: #f7faff;
  --header: rgba(255,255,255,.94);
  --blue: #0d67bf;
  --link: #0955a0;
  --on-blue: #fff;
  --teal: #08776e;
  --notice: #eaf7f5;
  --notice-ink: #205b59;
  --shadow: 0 20px 56px rgba(28,77,123,.12);
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","PingFang SC","Helvetica Neue",Arial,sans-serif;
}
html[data-theme="dark"] {
  color-scheme: dark;
  --ink: #e7eef8;
  --muted: #afc0d3;
  --line: #33475d;
  --control: #8b9db4;
  --surface: #142337;
  --soft: #1b2e45;
  --page: #0c1727;
  --header: rgba(12,23,39,.94);
  --blue: #85bbff;
  --link: #a1caff;
  --on-blue: #0b2441;
  --teal: #65d2c5;
  --notice: #153732;
  --notice-ink: #c5e9e1;
  --shadow: 0 20px 56px rgba(0,0,0,.14);
}
* { box-sizing: border-box; }
img { max-width: 100%; height: auto; }
html { scroll-behavior: smooth; scroll-padding-top: 112px; }
body { margin: 0; color: var(--ink); background: var(--page); line-height: 1.65; }
a { color: var(--link); text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }
button,input { font: inherit; }
:focus-visible { outline: 3px solid var(--blue); outline-offset: 4px; }
.wrap { width: min(1120px,calc(100% - 40px)); margin: 0 auto; }
.skip-link { position: fixed; top: -100px; left: 20px; z-index: 20; background: var(--surface); padding: 10px 16px; border-radius: 8px; }
.skip-link:focus { top: 12px; }
.site-header { position: sticky; top: 0; z-index: 10; background: var(--header); border-bottom: 1px solid var(--line); }
.nav { min-height: 72px; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 700; letter-spacing: -.02em; color: var(--ink); text-decoration: none; flex-shrink: 0; }
.brand img { width: 32px; height: 32px; border-radius: 8px; }
.nav-links { display: flex; align-items: center; flex-wrap: wrap; gap: 16px; font-size: 14px; }
.nav-links a { color: var(--ink); text-decoration: none; min-height: 44px; display: inline-flex; align-items: center; }
.nav-links a:hover { text-decoration: underline; }
.button,.theme-toggle { display: inline-flex; justify-content: center; align-items: center; min-height: 44px; padding: 8px 16px; border-radius: 10px; border: 1px solid var(--control); font-weight: 600; background: var(--surface); color: var(--ink); text-decoration: none; cursor: pointer; }
.button.primary { background: var(--blue); color: var(--on-blue); border-color: var(--blue); }
.theme-toggle { font-size: 13px; padding: 8px 12px; white-space: nowrap; }
.button:hover { text-decoration: none; filter: brightness(.96); }
.hero { padding: 72px 0 64px; display: grid; grid-template-columns: 1fr 1fr; align-items: center; gap: 48px; }
.eyebrow { color: var(--link); font-size: 13px; font-weight: 700; letter-spacing: .06em; }
h1 { margin: 14px 0 18px; font-size: clamp(36px,5vw,58px); line-height: 1.16; letter-spacing: -.04em; }
.lead { margin: 0; max-width: 640px; color: var(--muted); font-size: 18px; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.hero-card { margin: 0; padding: 12px; border: 1px solid var(--line); border-radius: 16px; background: var(--surface); box-shadow: var(--shadow); }
.hero-card img { width: 100%; display: block; border-radius: 8px; border: 1px solid var(--line); }
.caption { margin: 12px 4px 0; color: var(--muted); font-size: 13px; }
section { padding: 64px 0; }
.section-head { max-width: 700px; margin-bottom: 28px; }
h2 { margin: 0 0 12px; font-size: clamp(28px,4vw,38px); line-height: 1.25; letter-spacing: -.03em; }
.section-head p { margin: 0; color: var(--muted); }
.grid { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: 16px; }
.card { padding: 24px; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; }
.card h3 { margin: 0 0 8px; font-size: 18px; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }
.split { display: grid; grid-template-columns: 1fr 1fr; align-items: center; gap: 40px; }
.split img { width: 100%; border-radius: 12px; border: 1px solid var(--line); }
.checklist { margin: 20px 0 0; padding-left: 20px; color: var(--muted); }
.checklist li { padding: 6px 0; }
.notice { padding: 24px; border-left: 4px solid var(--teal); border-radius: 10px; background: var(--notice); color: var(--notice-ink); }
.prose { max-width: 800px; padding: 64px 0 80px; }
.prose h1 { font-size: clamp(34px,5vw,50px); }
.prose h2 { margin-top: 36px; font-size: 27px; }
.prose h3 { margin-top: 24px; font-size: 20px; }
.prose p,.prose li { color: var(--muted); }
.prose li { margin: 8px 0; }
.prose a { overflow-wrap: anywhere; }
footer { padding: 32px 0 44px; color: var(--muted); font-size: 13px; border-top: 1px solid var(--line); }
.footer-links { display: flex; flex-wrap: wrap; gap: 20px; margin-top: 10px; }
.footer-links a { display: inline-flex; align-items: center; min-height: 44px; }
.kicker { color: var(--link); font-weight: 650; }
.hash,.prose code { overflow-wrap: anywhere; }
.trial-panel { padding: 24px; margin: 32px 0; border: 1px solid var(--control); border-radius: 14px; background: var(--surface); }
.trial-panel label { display: block; margin-top: 20px; font-weight: 650; }
.trial-panel input { display: block; margin-top: 8px; padding: 12px; width: 100%; border: 1px solid var(--control); border-radius: 8px; color: var(--ink); background: var(--soft); font-family: ui-monospace,monospace; font-size: 14px; }
button:disabled { cursor: wait; opacity: .65; }
.qr-grid { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 24px; }
.qr-card { margin: 0; padding: 24px; background: var(--surface); border: 1px solid var(--line); border-radius: 14px; }
.qr-card img { display: block; width: min(100%,280px); height: auto; margin: 20px auto 0; }
.qr-card figcaption { margin-top: 16px; color: var(--muted); font-size: 14px; }
@media (max-width: 820px) {
  .hero,.split { grid-template-columns: 1fr; gap: 32px; }
  .hero { padding-top: 48px; }
  .grid { grid-template-columns: 1fr; }
  .nav { flex-wrap: wrap; padding: 12px 0; gap: 8px; }
  .nav-links { gap: 12px; }
  .nav-links .optional { display: none; }
}
@media (max-width: 520px) { .qr-grid { grid-template-columns: 1fr; } }
@media (max-width: 400px) {
  .wrap { width: calc(100% - 32px); }
  .brand { font-size: 15px; }
  .brand img { width: 28px; height: 28px; }
  .nav-links { gap: 8px; }
  .theme-toggle { padding-inline: 10px; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }