:root {
  --bg: #f7f8fb;
  --surface: #ffffff;
  --text: #1c2230;
  --muted: #5b6472;
  --accent: #1e3a8a;
  --accent-soft: #eef1fb;
  --border: #e3e6ee;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14171f;
    --surface: #1b1f2a;
    --text: #eef0f5;
    --muted: #a2a9b8;
    --accent: #8fa8f2;
    --accent-soft: #212745;
    --border: #2a2f3d;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  line-height: 1.6;
}

.wrap {
  max-width: 720px;
  margin: 0 auto;
  padding: 3rem 1.5rem 5rem;
}

header.hero {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 2rem;
}

header.hero .mark {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--accent);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
  flex-shrink: 0;
}

header.hero h1 {
  font-size: 1.35rem;
  margin: 0;
}

header.hero p {
  margin: 0.15rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

nav.top {
  display: flex;
  gap: 1.25rem;
  margin-bottom: 2.5rem;
  font-size: 0.95rem;
}

nav.top a {
  color: var(--muted);
  text-decoration: none;
  padding-bottom: 2px;
  border-bottom: 2px solid transparent;
}

nav.top a.active, nav.top a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

h2 {
  font-size: 1.15rem;
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
}

h2:first-of-type { margin-top: 0; }

h3 {
  font-size: 1rem;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

p, li { color: var(--text); }

ul { padding-left: 1.25rem; }
li { margin-bottom: 0.35rem; }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1.25rem 1.5rem;
  margin-bottom: 1.25rem;
}

.card h3 {
  margin-top: 0;
}

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

.effective {
  color: var(--muted);
  font-size: 0.9rem;
  margin-top: -0.5rem;
  margin-bottom: 2rem;
}

footer {
  margin-top: 3.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.85rem;
}

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

.button {
  display: inline-block;
  background: var(--accent);
  color: white !important;
  text-decoration: none;
  padding: 0.6rem 1.1rem;
  border-radius: 10px;
  font-size: 0.95rem;
  font-weight: 600;
}

.muted { color: var(--muted); }