CSS grid layout (from Wikipedia article)
CSS grid layout or CSS grid is a technique in Cascading Style Sheets that allows web developers to create complex responsive web design layouts more easily and consistently across browsers. There have been other webpage layout methods used previously including tables, the box model, and CSS flex box. It is currently a W3C Candidate Recommendation despite already being adopted by most major browsers.
CSS grid can create more asymmetrical layouts than the previous grid and layout options like CSS floats. It also allows for more standardized code that works across browsers. This is in contrast to relying on specific browser hacks or complicated workarounds.
One issue with using floats in CSS is if content gets added to one portion of the page it could disrupt the flow of the page and break the layout. This is due to the varying heights for layout elements. Though CSS flex box supports flexible layouts and provides the flexibility of creating complex layouts, it fails when the need for creating responsive layouts in 2-dimensional space arises. That is where CSS grid layout shines.