SCSS mixin to convert Photoshop drop shadows to CSS3 box-shadow
An Introduction to CSS Preprocessing - Speaker Deck
Create a CSS mixin in React using styled-components | egghead.io
Layered box-shadows via Sass mixin
CSS box-shadow support / sciter
css - Box-shadow only on div corners - Stack Overflow
Deep dive into sass
box-shadow inset problem · Issue #13 · matthieua/sass-css3-mixins · GitHub
Battle of the LESS Mixin Libraries: LESS Elements vs. LESS Hat vs. Bootstrap | Design Shack
Getting Deep Into Shadows | CSS-Tricks - CSS-Tricks
Bootstrap on Twitter: "We'll be bringing CSS variables to more components in each minor v5 release to make customization easier and even reduce file size in some cases. Consider this before and