On small screens (max-width: 600px) the admin bar doesn't stick to the top of the page, this is because at this breakpoint the admin bar switches from
position: fixed to
position: absolute and since the theme uses
position: relative for the
body the bar positions itself at the top of the
body element not the
I'm not sure why position relative is used on the
body but I removed it on my installation and it works fine so far.