/* 共通スタイル：common.css */
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", sans-serif;
  margin: 0;
  padding: 2rem 1rem;
  background: #f9f9f9;
  color: #333;
  line-height: 1.8;
  font-size: 16px;
}

header {
  background: #333;
  color: white;
  padding: 1.5rem 1rem;
  text-align: center;
}

header h1 {
  margin: 0;
  font-size: 1.6rem;
}

nav {
  margin-top: 0.5rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
}

nav a {
  color: #fff;
  text-decoration: none;
  font-weight: bold;
  font-size: 0.95rem;
}

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

main {
  max-width: 800px;
  margin: 2rem auto;
  background: white;
  padding: 2rem 1.5rem;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.05);
}

h2 {
  font-size: 1.25rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
}

p,
li {
  margin-bottom: 1rem;
}

ul {
  padding-left: 1.5rem;
}

code {
  background-color: #f0f0f0;
  padding: 0.2em 0.4em;
  border-radius: 4px;
  font-size: 0.95em;
}

a {
  color: #007acc;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

footer {
  margin-top: 4rem;
  padding: 1rem;
  text-align: center;
  color: #888;
  font-size: 0.85rem;
}

/* モバイル対応（幅600px以下） */
@media screen and (max-width: 600px) {
  body {
    font-size: 15px;
    padding: 1rem;
  }

  main {
    padding: 1.5rem 1rem;
    margin: 1rem auto;
  }

  header h1 {
    font-size: 1.4rem;
  }

  nav {
    flex-direction: column;
    align-items: center;
  }

  nav a {
    margin: 0.3rem 0;
  }

  h2 {
    font-size: 1.15rem;
  }
}