Padding and Retina: For some time i couldn't find the reason why some (but just very few) elements on my project appear slightly different on PC and Mac. Same browsers. Finally I fixed that by applying retina media query that divided at least my mac from rest. Could you explain maybe why it happens? I found it specially happens with padding.

The scenario is like this, say I have padding-top:5px; on element. Same element would display good on one (PC/Mac) and will be few (but not neccesarily 5) pixels shifted on others..

So padding and retina.. :) IDK, if that interests you I may do a PoC for this.