:root {
  --color-bg: #FAF7F1;
  --color-surface: #ffffff;
  --color-ink: #0F2A22;
  --color-ink-muted: #5A6B62;
  --color-primary: #1FB89B;
  --color-primary-hover: #168F78;
  --color-border: rgba(15, 42, 34, 0.08);
}
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0B0F0D;
    --color-surface: #141A17;
    --color-ink: #F0EDE5;
    --color-ink-muted: #9AA8A1;
    --color-primary: #3DD9BC;
    --color-primary-hover: #5DE3CB;
    --color-border: rgba(240, 237, 229, 0.08);
  }
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { min-height: 100vh; }
body {
  font-family: 'Satoshi', system-ui, sans-serif;
  background: var(--color-bg); color: var(--color-ink);
  line-height: 1.6; -webkit-font-smoothing: antialiased;
}
h1, h2, h3 {
  font-family: 'Clash Display', 'Satoshi', sans-serif;
  font-weight: 600; letter-spacing: -.01em;
}
a { color: var(--color-primary); text-decoration: underline; text-underline-offset: 3px; }
a:hover { color: var(--color-primary-hover); }

header {
  border-bottom: 1px solid var(--color-border); padding: 24px 0; margin-bottom: 48px;
}
.header-inner {
  max-width: 780px; margin: 0 auto; padding: 0 24px;
  display: flex; justify-content: space-between; align-items: center;
}
.brand {
  font-family: 'Clash Display', sans-serif; font-weight: 700; font-size: 20px;
  color: var(--color-primary); letter-spacing: .02em; text-decoration: none;
}
.back-link {
  color: var(--color-ink-muted); font-size: 14px; text-decoration: none;
  display: inline-flex; align-items: center; gap: 6px;
}
.back-link:hover { color: var(--color-primary); }

main {
  max-width: 780px; margin: 0 auto; padding: 0 24px 80px;
}
h1 { font-size: clamp(28px, 4vw, 40px); margin-bottom: 8px; }
.meta { color: var(--color-ink-muted); font-size: 14px; margin-bottom: 40px; }
h2 { font-size: 22px; margin: 40px 0 14px; }
h3 { font-size: 17px; margin: 28px 0 10px; }
p, ul, ol { margin-bottom: 16px; color: var(--color-ink); }
ul, ol { padding-left: 22px; }
li { margin-bottom: 6px; }
strong { font-weight: 600; }
small { color: var(--color-ink-muted); font-size: 13px; }

.callout {
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: 14px; padding: 18px 20px; margin: 20px 0;
}

footer {
  border-top: 1px solid var(--color-border); padding: 28px 0;
  font-size: 13px; color: var(--color-ink-muted); text-align: center;
}