JSON Schema Property 'css'

The list of CSS files to be injected into matching pages. These are injected in the order they appear in this array, before any DOM is constructed or displayed for the page.

"css": {
    "type": "array",
    "description": "The list of CSS files to be injected into matching pages. These are injected in the order they appear in this array, before any DOM is constructed or displayed for the page.",
    "uniqueItems": true,
    "items": {
        "$ref": "#/definitions/uri"
    }
}

• /properties/content_scripts/items[0]