This is for a mobile menu, which of course needs to be responsive. The longest child should set the width for all the other children .index needs to be full width and height with a background-color
i.stack.imgur.com/AJHct.png
Build Smart CSS-only Layouts with Flexbox
How to align an element to bottom with flexbox in CSS ? - GeeksforGeeks
How to center an element in CSS without adding a wrapper in HTML - Bejamas
html - How to prevent flexbox row from MOVING UP when other items are wrapped - Stack Overflow
A Complete Guide to Flexbox
A Guide to CSS Flexbox - CoderPad
Flexbox - Learn web development
Laying Out Views, Using Designer, Designer, Tools
How to align an element to bottom with flexbox in CSS ? - GeeksforGeeks
Center elements with flexbox - Webflow University Documentation