I'm trying to make my code
<div style="margin-top: 120px; margin-bottom: 10px; margin-left: 250px; text-align: center;">
<a href="/products"><img width="420" height="42" style="vertical-align:middle;" src="https://i.imgsafe.org/52c5068376.png" alt="PAF ENTRY"></a>
</div>
appear in the middle of the screen on both browser and mobile so it works on both, since when i try to go to my webpage on mobile it doesn't show up since it's not right in the middle. if that isn't possible a way to make two versions of the code 1 mobile only view and 1 browser only, since everything I've searched for this doesn't work.
link to the page: http://pafclub.bigcartel.com/entry
