Building a CSS Grid Overlay

Let's take a look at what it takes to build a grid overlay with CSS. It will be responsive, easily customizable and make heavy use of CSS variables (known more accurately as "CSS custom properties"). If you aren't familiar with custom properties, I'd highly recommend reading What is the difference between CSS variables and preprocessor variables? and watching Lea Verou's enlighting talk on using them.

This grid overlay that we're building will consider a developer tool, as in, a tool …

Building a CSS Grid Overlay is a post from CSS-Tricks