Flexbox
The parent (flex container) is responsible for controlling the layout of all its immediate children (flex items), rather than each child controlling its own layout.
There are 2 axes: the main axis and the cross axis.
https://vudav.github.io/flexbox-cheatsheet
https://yoksel.github.io/flex-cheatsheet
https://css-tricks.com/snippets/css/a-guide-to-flexbox
https://www.joshwcomeau.com/css/interactive-guide-to-flexbox/
https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Flexible_Box_Layout
https://developer.mozilla.org/en-US/docs/Learn/CSS/CSS_layout/Flexbox
flex-basis
https://every-layout.dev/blog/sidebar-flex-basis-clamp/