:root {
  --bg: #f5f7fb;
  --card: #ffffff;
  --text: #1c1f26;
  --muted: #5b6475;
  --accent: #1a5fd6;
  --rule: #e2e6ee;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1324;
    --card: #121c31;
    --text: #e8ecf4;
    --muted: #9aa5ba;
    --accent: #6ea6ff;
    --rule: #22304d;
  }
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.55 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}
main {
  max-width: 680px;
  margin: 32px auto;
  padding: 28px 24px 20px;
  background: var(--card);
  border-radius: 20px;
}
@media (max-width: 720px) {
  main { margin: 0; border-radius: 0; padding: 24px 16px; }
}
header { display: flex; align-items: center; gap: 16px; margin-bottom: 8px; }
header img { border-radius: 16px; flex: none; }
h1 { margin: 0; font-size: 28px; line-height: 1.2; }
.sub { margin: 2px 0 0; color: var(--muted); font-size: 15px; }
.lead { font-size: 18px; }
h2 { margin: 28px 0 6px; font-size: 20px; }
h3 { margin: 18px 0 2px; font-size: 17px; }
p, li { color: var(--text); }
ul { padding-left: 22px; }
a { color: var(--accent); }
.button {
  display: inline-block;
  padding: 12px 22px;
  border-radius: 12px;
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  text-decoration: none;
}
@media (prefers-color-scheme: dark) { .button { color: #0b1324; } }
footer {
  margin-top: 32px;
  padding-top: 14px;
  border-top: 1px solid var(--rule);
  font-size: 15px;
}