color section don't work on mobile

Hey Stilecatalini,
Sorry for the very late reply, this sounds like you are experiencing the fixed background limitation of the mobile IOS.
You will need to change the background to scroll for these devices. Please try this css in your General Styling > Quick CSS field or in the WordPress > Customize > Additional CSS field:

@media only screen and (max-width: 1024px) {
.avia-safari #top .avia-full-stretch{
background-attachment: scroll !important;
}
}

Then clear your browser cache and check.
Or you can try this technique.
If this doesn’t help then please link to a page with the issue.

Best regards,
Mike