packages/theme/templates/index.build.html

<!doctype html>
<html lang="{{ lang }}" data-theme="{{ themeMode }}">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width,initial-scale=1" />
    <meta name="generator" content="VuePress {{ version }}" />
    <meta name="theme" content="VuePress Theme Hope {{ themeVersion }}" />
    <style>
      html {
        background: var(--bg-color, #fff);
      }

      html[data-theme="dark"] {
        background: var(--bg-color, #1d1e1f);
      }

      body {
        background: var(--bg-color);
      }
    </style>
    <script>
      const userMode = localStorage.getItem("vuepress-theme-hope-scheme");
      const systemDarkMode =
        window.matchMedia &&
        window.matchMedia("(prefers-color-scheme: dark)").matches;

      if (userMode === "dark" || (userMode !== "light" && systemDarkMode)) {
        document.documentElement.setAttribute("data-theme", "dark");
      }
    </script>
    <!--vuepress-ssr-head-->
    <!--vuepress-ssr-styles-->
    <!--vuepress-ssr-preload-->
    <!--vuepress-ssr-prefetch-->
  </head>
  <body>
    <div id="app"><!--vuepress-ssr-content--></div>
    <!--vuepress-ssr-scripts-->
  </body>
</html>