<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <link rel="stylesheet" href="popup.css">
</head>
<body>
  <section id="title_section">
    タイトル
    <p id="page_title"></p>
    <button type="button" id="copy_title">コピー</button>
  </section>

  <section id="url_section">
    URL
    <p id="page_url"></p>
    <button type="button" id="copy_url">コピー</button>
  </section>

  <hr>
  <section id="all_section">
    <button type="button" id="copy_all">全てコピー</button>
  </section>

  <script src="popup.js"></script>
</body>
</html>

<!DOCTYPE html>
<html lang="ja">
<head>
  <meta charset="UTF-8">
  <link rel="stylesheet" href="popup.css">
</head>
<body>
  <table>
    <tr>
      <td>タイトル</td>
    </tr>
    <tr>
      <td>
        <p id="page_title"></p>
      </td>
      <td>
        <button type="button" id="copy_title">コピー</button>
      </td>
    </tr>
    <tr>
      <td>URL</td>
    </tr>
    <tr>
      <td>
        <p id="page_url"></p>
      </td>
      <td>
        <button type="button" id="copy_url">コピー</button>
      </td>
    </tr>
    <tr>
      <td></td>
      <td>
        <button type="button" id="copy_all">全てコピー</button>
      </td>
    </tr>
  </table>

  <script src="popup.js"></script>
</body>
</html>

Change structure of html from sections to table
Change structure of html from sections to table
