Within Splash, we give you three units of measure to choose from when styling text elements: pixels, ems and, rems.
When it comes to responsive design, it goes without saying that setting text-size in pixels should be avoided, but whether to use ems and rems is up for debate.
We'll spare you the intricacies of how these units two differ, but it's worth noting that rem stands for root em. Simply put, ems are determined by the font size of the element on which they are being used and rems are determined by the root font size specified for the entire page.
With that in mind, we recommend using rems for text within Splash because doing so allows all type on the page to render based on the same root value.
You may notice that toggling between em and rem within the CMS doesn't seem to have much of a visual effect; but, setting your type in rems is a precaution that ensures proper type rendering no matter the circumstances.