body {
    font-family: "Meiryo", sans-serif;
    background: #ffffff;
    color: #333;
    font-size: 18px;
    line-height: 1.8;
    padding: 40px 20px;
    max-width: 950px;
    margin: 0 auto;
  }
  
  h1 {
    font-size: 36px;
    font-weight: bold;
    margin-bottom: 30px;
    border-bottom: 2px solid #444;
    padding-bottom: 10px;
    text-align: center;
  }
  
  h2 {
    font-size: 24px;
    font-weight: bold;
    margin-top: 40px;
    margin-bottom: 15px;
    border-left: 5px solid #007bff;
    padding-left: 10px;
    color: #222;
  }
  
  p {
    margin-bottom: 20px;
  }
  
  ul {
    padding-left: 1.5em;
    margin-bottom: 20px;
  }
  
  ul li {
    margin-bottom: 10px;
    list-style: disc;
  }
  
  footer {
    text-align: center;
    margin-top: 60px;
    font-size: 14px;
    color: #777;
  }
  
  /* ───── レスポンシブ ───── */
  @media screen and (max-width: 768px) {
    body {
      font-size: 18px;
      padding: 30px 15px;
      max-width: 800px;
    }
  
    h1 {
      font-size: 32px;
    }
  
    h2 {
      font-size: 20px;
    }
  }

  .back-to-index {
    text-align: center;
    margin-top: 50px;
  }
  
  .back-to-index a {
    display: inline-block;
    background: #007bff;
    color: #fff;
    text-decoration: none;
    padding: 12px 25px;
    font-size: 18px;
    border-radius: 6px;
    transition: 0.3s ease;
  }
  
  .back-to-index a:hover {
    background: #0056b3;
  }