Extensão do Chrome Adicione CSS à página

{
  "name": "Extension Name,
  "description": "description",
  "version": "1.0",
  "manifest_version": 3,
  "icons": {
    "48": "/icons/48.png",
    "128": "/icons/128.png"
	},
  
  "content_scripts": [{
    "matches": ["<all_urls>"],
    "css": ["mystyle.css"]
	}]
}
Button