YouTube dark mode

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "YouTube dark mode",
  "version": "1.0.0",
  "description": "This is my very first cool extension",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "https://*.youtube.com/*"
      ],
      "exclude_matches": [
        "https://*.youtube.com/watch*"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "bookmarks"
  ],
  "icons": {
    "16": "hello_extensions.png",
    "32": "hello_extensions.png",
    "128": "hello_extensions.png"
  },
  "browser_action": {
    "default_title": "udemy extension online course",
    "default_popup": "popup.html"
  }
}