body {
      font-family: 'Segoe UI', sans-serif;
      background: #fdfdfd;
      padding: 1em;
      margin: 0;
      display: flex;
      flex-direction: column;
      align-items: center;
    }
    header {
      text-align: center;
      margin-bottom: 1em;
    }
    header img {
      width: 80px;
      height: auto;
    }
    h1 {
      margin: 0.2em 0;
      font-size: 1.5em;
    }
    .quiz-box {
      background: white;
      padding: 1em;
      border-radius: 12px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.1);
      max-width: 500px;
      width: 100%;
    }
    .question {
      font-size: 1.1em;
      margin-bottom: 1em;
    }
    .options button {
      display: block;
      margin: 0.5em 0;
      padding: 0.8em;
      width: 100%;
      border: none;
      border-radius: 8px;
      background: #e0e0e0;
      cursor: pointer;
      font-size: 1em;
    }
    .options button.correct {
      background: #a5d6a7;
    }
    .options button.wrong {
      background: #ef9a9a;
    }
    #next-btn {
      margin-top: 1em;
      padding: 0.8em;
      width: 100%;
      border: none;
      border-radius: 8px;
      background: #64b5f6;
      color: white;
      font-size: 1em;
      display: none;
    }

    .menu {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 1em;
      margin-top: 2em;
    }
    .menu button {
      padding: 1em 2em;
      font-size: 1.2em;
      border: none;
      border-radius: 8px;
      background-color: #64b5f6;
      color: white;
      cursor: pointer;
    }
    .menu button:hover {
      background-color: #42a5f5;
    }

/*用語集*/
    .term-table {
      width: 100%;
      max-width: 800px;
      border-collapse: collapse;
      margin: auto;
      background: white;
    }
    th, td {
      padding: 0.8em;
      border: 1px solid #ccc;
      text-align: left;
    }
    th {
      background: #e0f2f1;
    }
    .category-heading {
      margin-top: 2em;
      font-size: 1.2em;
      font-weight: bold;
      color: #4caf50;
      text-align: center;
    }

    @media screen and (max-width: 600px) {
      .quiz-box {
        padding: 0.8em;
      }
    }