/**
* @typedef {object} Phaser.Types.Loader.FileTypes.CSSFileConfig
*
* @property {string} key - The key of the file. Must be unique within the Loader.
* @property {string} [url] - The absolute or relative URL to load the file from.
* @property {string} [extension='css'] - The default file extension to use if no url is provided.
* @property {Phaser.Types.Loader.XHRSettingsObject} [xhrSettings] - Extra XHR Settings specifically for this file.
*/