CSS Grid Inspector in Firefox Nightly, July 2017

CSS Grid is changing how layout is done on the web. It can be hard to write CSS using Grid without being able to see a visual representation of what’s happening. Our team at Mozilla created the Grid Inspector Tool to make it possible to see the grid lines, and shipped that tool in Firefox 52. Now we are taking things to the next level — adding a new Layout Panel to the Firefox Developer Tools, with the ability to change the color of the grid lines, to see the positive line numbers, to see grid area names, and refine other ways in which the Grid Inspector works. In this video, Jen Simmons gives a tour of what’s new and how to use it.