Hide background image in certain media query values

I'm trying to hide the background image I'm using only in mobile view.

html{
background: #fff url('//www.xxxxxxxxx.xxx/gray.jpg') center top no-repeat;
background-attachment: initial;
background-size: contain;
background-position-y: 0;
}

But when I do this:

@media (max-width: 425px){
background: transparent !important;
}

The background doesn't recognize the query rule set for HTML. How can I do this? What am I doing wrong?