[deleted] Yes, tested at https://devflarum.xyzz.work/ and the happens the same. Not sure if that is a bug or if it's done intentionaly.
Anyway, if the background is viewed on desktop it should be also viewed and mobile. Seems that the white background appears when width is lower than 767px:
@media (max-width: 767px)
So a possible fix for you will be:
body {
background-image: url("http://i.imgur.com/A9RUUBc.gif");
background-color: transparent;
}
@media (max-width: 767px) {
.App-content {
background: none;
}
}
And a personal suggestion, that background is terrible. I can't keep reading a forum with it for more than 3 seconds ?