Learn how to create CSS layouts that are self-governing, using Flexbox and Grid.
*IMPORTANT:* The code at 4.02 is incomplete. You need to add `flex-basis: 0` to the `.not-sidebar` element. Combined with `flex-grow: 666` this essentially means "grow from 0 to an absurdly high proportion of the available space".
Transcript (includes all the code samples): https://gist.github.com/Heydon/c0b1d088461c64370d6fe1a19bff4b9f