Hi Behzad. The way to fix this issue is to change your variant to 400px. I make all mobile variants this size and they display perfectly. I call the variant : Smartphon 400px
It will display on a tablet the same way it does on a laptop or desktop, and will display correctly on any phone also. As you have already made the variant 480px, you will need to resize your page elements to fit the amended 400px width.