Have you played around with the new CSS Flexbox or Grid specs?
Importance
High
Quiz Topics
CSS
Flexbox is mainly meant for 1-dimensional layouts while Grid is meant for 2-dimensional layouts.
Flexbox solves many common problems in CSS, such as vertical centering of elements within a container, sticky footer, etc. famous CSS frameworks like Bootstrap and Bulma are based on Flexbox, and Flexbox is still the tested and proven way to create layouts.
Grid is by far the most intuitive approach for creating grid-based layouts but browser support is not that wide at the moment. Many layout problems can already be solved with Flexbox, so there's not a huge need for Grid.