:root {
  --ink: #16202b;
  --muted: #5c6b7a;
  --line: #dde4ea;
  --bg: #ffffff;
  --accent: #1f6feb;
  --panel: #f6f8fa;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

.wrap {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 24px;
}

.site-header {
  border-bottom: 1px solid var(--line);
  background: #fff;
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 64px;
  gap: 16px;
  flex-wrap: wrap;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 650;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: -0.01em;
}

nav a {
  color: var(--muted);
  text-decoration: none;
  margin-left: 20px;
  font-size: 15px;
}

nav a:hover { color: var(--ink); }

.hero {
  padding: 64px 0 32px;
  max-width: 720px;
}

h1 {
  font-size: clamp(28px, 4vw, 40px);
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: 0 0 16px;
}

.lead {
  color: var(--muted);
  font-size: 18px;
  margin: 0 0 28px;
}

.button {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  padding: 12px 20px;
  border-radius: 8px;
  font-weight: 600;
}

.button:hover { filter: brightness(1.07); }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  padding: 24px 0 8px;
}

.cards article {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 22px;
}

h2 {
  font-size: 18px;
  margin: 0 0 10px;
  letter-spacing: -0.01em;
}

.cards p, .note p, .page p { margin: 0; color: var(--muted); }

.note {
  margin: 32px 0 56px;
  padding: 24px;
  border-left: 3px solid var(--accent);
  background: var(--panel);
  border-radius: 0 12px 12px 0;
}

.page { padding: 48px 0 64px; max-width: 720px; }
.page p + p { margin-top: 14px; }

dl { margin: 0; }
dt { font-weight: 600; margin-top: 18px; }
dd { margin: 4px 0 0; color: var(--muted); }

.site-footer {
  border-top: 1px solid var(--line);
  padding: 22px 0;
  color: var(--muted);
  font-size: 14px;
}

.site-footer .wrap {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.site-footer a { color: var(--muted); }