* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Segoe UI", Roboto, sans-serif;
  color: #1d1d1f;
  background: #fbfbfd;
  line-height: 1.7;
}
header {
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
  color: #fff;
  padding: 60px 24px;
  text-align: center;
}
header h1 { font-size: 36px; font-weight: 700; margin-bottom: 12px; }
header p { font-size: 18px; color: #c8d6e5; max-width: 600px; margin: 0 auto; }
nav {
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid #e0e0e0;
  padding: 12px 24px;
  text-align: right;
  position: sticky;
  top: 0;
  z-index: 10;
}
nav a { color: #0066cc; text-decoration: none; font-size: 14px; margin-left: 16px; }
nav a:hover { text-decoration: underline; }
main { max-width: 800px; margin: 0 auto; padding: 48px 24px; }
section { margin-bottom: 48px; }
section h2 {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid #0f3460;
  color: #0f3460;
}
ul { padding-left: 24px; margin-top: 8px; }
li { margin-bottom: 6px; }
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  margin-top: 16px;
}
.feature-card {
  background: #fff;
  border: 1px solid #e8e8e8;
  border-radius: 12px;
  padding: 20px;
}
.feature-card h3 { font-size: 16px; margin-bottom: 8px; color: #0f3460; }
.feature-card p { font-size: 14px; color: #555; }
.btn {
  display: inline-block;
  background: #0066cc;
  color: #fff;
  padding: 12px 28px;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 500;
  margin-top: 8px;
  margin-right: 8px;
}
.btn:hover { background: #0055aa; }
.btn-secondary {
  background: transparent;
  color: #0066cc;
  border: 1px solid #0066cc;
}
.btn-secondary:hover { background: #f0f4ff; }
footer {
  text-align: center;
  padding: 32px 24px;
  color: #888;
  font-size: 13px;
  border-top: 1px solid #e8e8e8;
}
footer a { color: #666; }
.license-note { font-size: 14px; color: #666; margin-top: 8px; }
.markdown-body h1 { font-size: 24px; font-weight: 600; margin-bottom: 16px; padding-bottom: 8px; border-bottom: 2px solid #0f3460; color: #0f3460; }
.markdown-body h2 { font-size: 20px; font-weight: 600; margin-top: 32px; margin-bottom: 12px; color: #1d1d1f; }
.markdown-body ul { padding-left: 24px; margin-top: 8px; }
.markdown-body li { margin-bottom: 6px; }