chromium/chrome/browser/resources/tab_search/tab_search.html

<!doctype html>
<html dir="$i18n{textdirection}" lang="$i18n{language}">
<head>
  <meta charset="utf-8">
  <title>Tab Search</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 {
      --white-rgb: 255, 255, 255;
    }

    html,
    body {
      width: 320px;
    }

    body {
      /* Using a var here for the background color is not currently an issue for
         Tab Search UI as it is shown asynchronously after the onload handler of
         the main frame has completed. */
      background-color: var(--color-tab-search-background);
      margin: 0;
    }
  </style>
</head>
<body>
  <tab-search-app></tab-search-app>
  <script type="module" src="tab_search.js"></script>
</body>
</html>