How do you adjust site margins for a tablet iPad device

The margins on my site look fine for desktop and mobile. However on a tablet device like an iPad they are reduce to zero. Can anyone offer any advice or CSS code to fix this please? Image grabs attached for reference. Please do request access to my site should that help. Thanks

https://brucemytton.co.uk/work

Add to Website Tools > Custom CSS

@media screen and (min-width:768px) and (max-width:1024px) {
div#gridThumbs {
    padding-left: 3vw !important;
    padding-right: 3vw !important;
}
}

Thank you @tuanphan, I have set the 'Site Margin Spacing' in the 'Site Styles' to 0vw, and added the code you've supplied, but that hasn't worked.

When viewed on an iPad only, the margins for all pages reduce to zero margin, no doubt because the overall site margins are set to 0vw. I would like the same margin, around 7vw, on all pages, are you able to supply the code for that please? 

https://brucemytton.co.uk/work 

A few other things...

1. The 'Targeted Solutions' logo in the footer looks a lot smaller on an ipad. Can this be made bigger with code?

2. The slide show on the homepage doesn't show /play on an ipad – any ideas why not?
https://brucemytton.co.uk/ 

3. Similarly, this page has mp4 videos added to it but they don't show on an ipad
https://brucemytton.co.uk/work/rn

It's an old ipad air, software version 12.5.7, it won't update to a newer version unfortunately.

Thanks for your help!

Can you add & keep code in CSS box? I can check it again easier