chromium/chrome/browser/resources/side_panel/reading_list/reading_list.html

<!doctype html>
<html dir="$i18n{textdirection}" lang="$i18n{language}">
<head>
  <meta charset="utf-8">
  <title>$i18n{title}</title>
  <link rel="stylesheet" href="chrome://theme/colors.css?sets=ui,chrome">
  <link rel="stylesheet" href="chrome://resources/css/text_defaults_md.css">
  <style>
    html,
    body {
      background: var(--color-side-panel-content-background);
      margin: 0;
    }
  </style>
</head>
<body>
  <reading-list-app></reading-list-app>
  <script type="module" src="reading_list_app.js"></script>
  </script>
</body>
</html>