我想更改用户按下按钮时的背景颜色。
我有两个主要职能：darkTheme()用于暗模式，lightTheme()用于亮模式。

JavaScript语言

function changeAppearence() {
  let themeForPage = localStorage.getItem('theme');
  if (themeForPage === 'light'){
    lightTheme();
  } else if (themeForPage === 'dark'){
    darkTheme();
  } else {
    darkTheme();
  }
}

function darkTheme() {
  localStorage.setItem('theme', 'dark');

  document.getElementById('headerMainMenu').style.backgroundColor = '#212529';
  document.body.style.backgroundColor = '#343a40';
  document.body.style.color = 'white';

}

function lightTheme() {
  localStorage.setItem('theme', 'light');

  document.getElementById('headerMainMenu').style.backgroundColor = 'white';
  document.body.style.backgroundColor = 'white';
  document.body.style.color = 'white';

}

但在键入npm start命令后，我得到以下错误：

错误消息：

App threw an error during load
ReferenceError: document is not defined
    at darkTheme (/Users/user/Documents/#4_Website_ Development/Electron/electron-app/main.js:76:3)
    at changeAppearence (/Users/user/Documents/#4_Website_ Development/Electron/electron-app/main.js:15:5)
    at Object.<anonymous> (/Users/user/Documents/#4_Website_ Development/Electron/electron-app/main.js:8:1)
    at Module._compile (internal/modules/cjs/loader.js:1078:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1108:10)
    at Module.load (internal/modules/cjs/loader.js:935:32)
    at Module._load (internal/modules/cjs/loader.js:776:14)
    at Function.f._load (electron/js2c/asar_bundle.js:5:12913)
    at loadApplicationPackage (/Users/user/Documents/#4_Website_ Development/Electron/electron-app/node_modules/electron/dist/Electron.app/Contents/Resources/default_app.asar/main.js:110:16)
    at Object.<anonymous> (/Users/user/Documents/#4_Website_ Development/Electron/electron-app/node_modules/electron/dist/Electron.app/Contents/Resources/default_app.asar/main.js:222:9)

我还尝试在JavaScript文件中创建一个简单的document.body.style.color = 'white';，但没有任何函数，但我得到了同样的错误。