body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background-color: #f7f7f7;
  color: #222;
}

header {
  background-color: #ffffff;
  border-bottom: 1px solid #ddd;
  padding: 1rem 0;
}

.container {
  width: 95%;
  max-width: 980px;
  margin: 0 auto;
}

h1 {
  margin: 0 0 0.25rem;
  font-size: 1.8rem;
}

.subtitle {
  margin: 0 0 0.75rem;
  color: #555;
}

h2, h3 {
  margin-top: 1.4rem;
  margin-bottom: 0.6rem;
}

p {
  line-height: 1.6;
  margin-bottom: 0.8rem;
}

nav a {
  margin-left: 0.75rem;
  text-decoration: none;
  color: #0366d6;
  font-size: 0.95rem;
}

nav a:hover {
  text-decoration: underline;
}

main {
  padding: 1.5rem 0 2.5rem;
}

ul {
  padding-right: 1.2rem;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.95rem;
}

table th, table td {
  border: 1px solid #ddd;
  padding: 0.5rem;
  vertical-align: top;
}

table th {
  background-color: #f0f0f0;
}

.notice {
  background-color: #fffbe6;
  border: 1px solid #ffe58f;
  padding: 0.75rem;
  border-radius: 4px;
  font-size: 0.9rem;
}

footer {
  border-top: 1px solid #ddd;
  background-color: #fafafa;
  padding: 1rem 0;
  font-size: 0.85rem;
  color: #555;
  margin-top: 1rem;
}