{
"background.fullscreen": {
"image": "https://pathtoimage.png", // url of your image
// "image": ["https://pathtoimage.png"], // An array may be useful when set interval for carousel
"opacity": 0.91, // 0.85 ~ 0.95 recommended
"size": "cover", // also css, `cover` to self-adaption (recommended)，or `contain`、`200px 200px`
"position": "center", // alias to `background-position`, default `center`
"interval": 0 // seconds of interval for carousel, default `0` to disabled.
}
}