:root {
  color-scheme: light dark;
  --bg: #f7f8fb;
  --surface: #ffffff;
  --text: #1b2533;
  --muted: #526174;
  --line: #d9e0ea;
  --accent: #126b5f;
  --accent-strong: #0d4f47;
  --soft: #eef6f4;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.55;
  background: var(--bg);
  color: var(--text);
}
a { color: var(--accent-strong); }
.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}
.nav {
  max-width: 980px;
  margin: 0 auto;
  padding: 18px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.brand {
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}
.nav-links {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}
.nav-links a {
  color: var(--muted);
  text-decoration: none;
}
.nav-links a[aria-current="page"] {
  color: var(--accent-strong);
  font-weight: 700;
}
main {
  max-width: 980px;
  margin: 0 auto;
  padding: 42px 20px 64px;
}
.hero {
  display: grid;
  gap: 16px;
  margin-bottom: 28px;
}
h1 {
  margin: 0;
  font-size: 34px;
  line-height: 1.15;
  letter-spacing: 0;
}
.lede {
  margin: 0;
  max-width: 760px;
  color: var(--muted);
  font-size: 18px;
}
.panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 22px;
  margin: 18px 0;
}
h2 {
  margin: 0 0 10px;
  font-size: 22px;
  line-height: 1.25;
}
ul { padding-left: 22px; }
li + li { margin-top: 6px; }
.callout {
  background: var(--soft);
  border-color: #b9d9d3;
}
.meta {
  color: var(--muted);
  font-size: 14px;
}
.button-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 16px;
}
.button {
  display: inline-block;
  border: 1px solid var(--accent);
  border-radius: 6px;
  padding: 10px 14px;
  color: #ffffff;
  background: var(--accent);
  text-decoration: none;
  font-weight: 700;
}
.button.secondary {
  color: var(--accent-strong);
  background: transparent;
}
.footer {
  border-top: 1px solid var(--line);
  color: var(--muted);
  background: var(--surface);
}
.footer-inner {
  max-width: 980px;
  margin: 0 auto;
  padding: 20px;
  font-size: 14px;
}
@media (max-width: 640px) {
  main { padding-top: 30px; }
  h1 { font-size: 28px; }
  .lede { font-size: 16px; }
  .panel { padding: 18px; }
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111821;
    --surface: #172231;
    --text: #ecf2f8;
    --muted: #b7c4d2;
    --line: #304154;
    --accent: #20a08f;
    --accent-strong: #7ad7cb;
    --soft: #15352f;
  }
  .button { color: #071916; }
}