:root {
  --bg: #f7f3ee;
  --surface: #ffffff;
  --text: #1d1d1f;
  --muted: #5b5b63;
  --accent: #1a6fe8;
  --accent-soft: #e3edfc;
  --border: #e4ddd4;
  --radius: 18px;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #141416;
    --surface: #1e1e22;
    --text: #f2f2f4;
    --muted: #a6a6ae;
    --accent: #5b9bff;
    --accent-soft: #1d2a40;
    --border: #2e2e34;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
a { color: var(--accent); text-underline-offset: 2px; }
.wrap { max-width: 880px; margin: 0 auto; padding: 0 20px; }
header.site { padding: 18px 0; }
header.site .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); text-decoration: none; font-weight: 650; font-size: 19px; }
.brand img { width: 32px; height: 32px; }
nav.site { display: flex; gap: 18px; flex-wrap: wrap; font-size: 15px; }
nav.site a { color: var(--muted); text-decoration: none; }
nav.site a:hover, nav.site a[aria-current="page"] { color: var(--text); }
main { padding: 24px 0 64px; }
.hero { text-align: center; padding: 40px 0 24px; }
.hero img { width: 168px; height: 168px; }
.hero h1 { font-size: clamp(34px, 6vw, 52px); line-height: 1.1; margin: 18px 0 12px; letter-spacing: -0.02em; }
.hero p.lead { font-size: 20px; color: var(--muted); max-width: 620px; margin: 0 auto 26px; }
.button { display: inline-block; background: var(--accent); color: #fff; text-decoration: none; font-weight: 600; padding: 12px 22px; border-radius: 999px; }
.button.secondary { background: var(--accent-soft); color: var(--accent); }
.button[aria-disabled="true"] { background: var(--accent-soft); color: var(--muted); pointer-events: none; }
.actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.actions.start { justify-content: flex-start; margin: 20px 0 4px; }
.note { color: var(--muted); font-size: 14px; margin-top: 12px; }
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; margin-top: 40px; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; }
.card h3 { margin: 0 0 6px; font-size: 18px; }
.card p { margin: 0; color: var(--muted); font-size: 15.5px; }
article { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 28px clamp(20px, 4vw, 40px); }
article h1 { margin-top: 0; font-size: 32px; letter-spacing: -0.01em; }
article h2 { font-size: 21px; margin-top: 32px; }
article p, article li { color: var(--text); }
.muted { color: var(--muted); }
footer.site { border-top: 1px solid var(--border); padding: 22px 0 40px; font-size: 14px; color: var(--muted); }
footer.site .wrap { display: flex; gap: 18px; flex-wrap: wrap; justify-content: space-between; }
footer.site nav { display: flex; gap: 16px; flex-wrap: wrap; }
footer.site a { color: var(--muted); }
@media (max-width: 600px) { .hero h1 br { display: none; } .hero img { width: 128px; height: 128px; } }