html {
    scroll-behavior: smooth;
  }

  body {
    margin: 0;
    font-family: "Hiragino Sans", "Yu Gothic", sans-serif;
    font-weight: 500;
    color: #222;
    line-height: 1.8;

    /* 背景画像を繰り返し */
    background-image: url("banner.jpg");
    background-repeat: repeat;
    background-size: 700px auto;
  }

  /* 中央の白い帯 */
  .page {
    width: min(75%, 1200px);
    min-height: 100vh;
    margin: 0 auto;
    background: rgba(255, 255, 255, 0.90); /* ← 透明度 */
    padding: 60px 50px;
    box-sizing: border-box;
  }

  header {
    text-align: center;
    padding: 40px 0;
  }

  h1 {
    font-size: 35px;
    font-weight: 500;
  }

  h2 {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-top: 55px;
    font-weight: 500;
    border-bottom: none;
  }

  h2::after {
    content: "";
    flex: 1;
    height: 1px;
    background: #a0a0a0;
  }

  /* ハンバーガーボタン */
  .hamburger {
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 1000;
    background: rgba(255,255,255,0.9);
    border: 1px solid #ddd;
    padding: 10px 12px;
    cursor: pointer;
    font-size: 32px;
  }

  .hamburger:hover {
    background: #f7f7f7;
  }

  /* メニュー：左からスライド */
  nav {
    position: fixed;
    top: 0;
    left: -260px;
    width: 220px;
    height: 100vh;
    background: rgba(255, 255, 255, 0.95);
    border-right: 1px solid #ccc;
    padding: 80px 20px;
    box-sizing: border-box;
    transition: left 0.3s ease;
    z-index: 999;
  }

  nav.open {
    left: 0;
  }

  nav a {
    display: block;
    margin: 15px 0;
    color: #333;           /* 青をやめる */
    text-decoration: none; /* 下線を消す */
    font-size: 18px;
  }

  nav a:hover {
    color: #666;
  }

  /* トップに戻るボタン：矢印を太く */
  .top-button {
    position: fixed;
    right: 25px;
    bottom: 25px;
    background: rgba(255,255,255,0.9);
    color: black;
    text-decoration: none;
    padding: 10px 15px;
    border-radius: 4px;
    font-size: 20px;
    font-weight: bold;
  }

  .top-button:hover {
    background: #555;
  }

  /* スマホ対応 */
  @media (max-width: 800px) {
    .page {
      width: 90%;
      padding: 50px 25px;
    }
  }