html - Flexbox column align items same width but centered without wrapper ( css-only) - Stack Overflow

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

Equal Columns With Flexbox: It's More Complicated Than You Might Think

How the Bootstrap Grid Really Works, by Carol Skelly, WDstack

A Guide to CSS Flexbox - CoderPad

Grid

html - Flexbox layout - aligning element at the edge of one another - Stack Overflow

How to align an element to bottom with flexbox in CSS ? - GeeksforGeeks

A Complete Guide to Flexbox

A Guide to CSS Flexbox - CoderPad

Equal height layouts with flexbox - Webflow University Documentation

html - How can I make my flexbox grid have 2 rows and 3 columns, but still be centered? - Stack Overflow

Ordering flex items - CSS: Cascading Style Sheets

css - flex setting items below each other - Stack Overflow

Flexbox - Webflow University Documentation

Controlling ratios of flex items along the main axis - CSS: Cascading Style Sheets