I have to create an extension which is fully responsive. But I face an issue. When I open my extension it doesn’t capture full screen. What did I do? [closed]

This is manifest.json file :

{
“manifest_version”: 3,
“name”: “Flixxit”,
“version”: “3”,
“permissions”: [“activeTab”],

"action": {
  "default_popup": "Plugin.html",
  "default_icon": "logo.png"
},
"icons": {
    "128": "logo.png"
},
"permissions": [
    "activeTab",
    "contextMenus",
    "storage"
  ]     

}

I have to build up an extension which is fully responsive and capture whole window screen.