Stylo

{
    "update_url": "https:\/\/clients2.google.com\/service\/update2\/crx",
    "name": "Stylo",
    "version": "2.0",
    "description": "Allows you to apply and persist custom CSS to any web page.",
    "manifest_version": 2,
    "browser_action": {
        "default_popup": "popup.html",
        "default_icon": {
            "16": "images\/icon16.png",
            "32": "images\/icon32.png",
            "48": "images\/icon48.png"
        }
    },
    "icons": {
        "16": "images\/icon16.png",
        "32": "images\/icon32.png",
        "48": "images\/icon48.png"
    },
    "content_scripts": [
        {
            "matches": [
                "https:\/\/mail.google.com\/*"
            ],
            "css": [
                "gmail.css"
            ]
        }
    ],
    "content_security_policy": "script-src 'self' https:\/\/mail.google.com\/*; object-src 'self'"
}