:root {
  --bg: #f4faf8;
  --surface: #ffffff;
  --text: #17201e;
  --muted: #55605d;
  --accent: #006b5f;
  --border: #d7e3df;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1514;
    --surface: #171f1d;
    --text: #e3ebe8;
    --muted: #9fb0ab;
    --accent: #6bd6c3;
    --border: #2a3532;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

header, main, footer {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 16px;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 24px;
  padding-bottom: 8px;
}

.brand {
  font-weight: 700;
  font-size: 20px;
  color: var(--text);
  text-decoration: none;
}

nav a { margin-left: 16px; color: var(--muted); text-decoration: none; }
nav a:hover { color: var(--accent); }

main { padding-top: 24px; padding-bottom: 48px; }

h1 { font-size: 32px; line-height: 1.2; margin: 0 0 16px; }
h2 { font-size: 21px; margin: 32px 0 8px; }

a { color: var(--accent); }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
  margin: 16px 0;
}

.lead { font-size: 19px; color: var(--muted); }
.muted { color: var(--muted); font-size: 15px; }
.check { font-size: 48px; line-height: 1; margin-bottom: 8px; }

ul { padding-left: 22px; }

footer {
  border-top: 1px solid var(--border);
  padding-top: 16px;
  padding-bottom: 32px;
  color: var(--muted);
  font-size: 14px;
}

footer a { color: var(--muted); margin-right: 16px; }

@media (max-width: 480px) {
  h1 { font-size: 26px; }
  nav a { margin-left: 12px; }
}