CSS grid tutorial
Alex Chan in The Good, the Bad, and the Gutters:
To help me understand how this layout works, I’m going to step through it and explain how I built the new version of the page.
You won't find a clearer and more understandable walkthrough of how to set up and style a CSS grid than this one from Alex. Making a note of their trick for fixed height for the cover images for my reading log which is crying out for exactly that.
Update: Inspired by Alex, I've updated the reading log CSS to use fixed height instead of fixed width. Looks much better!