:root {
  --bg: #f4f5f7;
  --surface: #ffffff;
  --text: #1a1d26;
  --muted: #6b7280;
  --border: #e8eaed;
  --primary: #4ade80;
  --primary-dark: #22c55e;
  --max-width: 720px;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}

a {
  color: var(--primary-dark);
}

a:hover {
  text-decoration: none;
}

.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 16px 20px;
}

.site-header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
  font-weight: 800;
  font-size: 18px;
  letter-spacing: -0.02em;
}

.logo-mark {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  font-size: 14px;
  font-weight: 600;
}

.nav a {
  color: var(--muted);
  text-decoration: none;
}

.nav a:hover,
.nav a.active {
  color: var(--primary-dark);
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 32px 20px 64px;
}

article {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 32px 28px;
}

h1 {
  margin: 0 0 8px;
  font-size: 28px;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.2;
}

.updated {
  margin: 0 0 28px;
  color: var(--muted);
  font-size: 14px;
}

h2 {
  margin: 28px 0 10px;
  font-size: 18px;
  font-weight: 700;
}

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

p,
ul {
  margin: 0 0 14px;
}

ul {
  padding-left: 22px;
}

li {
  margin-bottom: 6px;
}

.site-footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px 40px;
  text-align: center;
  color: var(--muted);
  font-size: 13px;
}

.hero {
  text-align: center;
  padding: 48px 20px 24px;
}

.hero h1 {
  font-size: 36px;
}

.hero p {
  color: var(--muted);
  font-size: 18px;
  max-width: 480px;
  margin: 12px auto 24px;
}

.card-grid {
  display: grid;
  gap: 16px;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px 48px;
}

.card {
  display: block;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s ease;
}

.card:hover {
  border-color: var(--primary);
}

.card h2 {
  margin: 0 0 6px;
  font-size: 18px;
}

.card p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 480px) {
  article {
    padding: 24px 18px;
  }

  h1 {
    font-size: 24px;
  }
}