Sass Helpers for Older Browsers

Nate goes through what’s needed to support older versions of IE and how Sass can help fix them easily. Not the helpers themselves, but contain links to other resources. Source: Sass Helpers for Older Browsers

Understanding and Using rem Units in CSS

Adrian Sandu explains some of the history of techniques using em and rem units in CSS, and shows some practical uses for the rem unit. More about rem. And default font-size turns out 16px. Source: Understanding and Using rem Units in CSS

A Look at Length Units in CSS

Gajendar Singh explains and demonstrates the different length units available in CSS, including absolute, relative, and viewport-relative units. Turns out there are many length units. Although not all recommended for development. Also discover the mystery behind em and getting to know with rem. Source: A Look at Length Units in CSS