flexbox - button sticks to bottom

Solved by Flexbox — Cleaner, hack-free CSS

How would I push the button to the bottom of the CSS flexbox in such case? - The freeCodeCamp Forum

CSS Flexible Box Layout Module Level 1

flexbox Archives - WP Beaches

Aligning Last Item to the Bottom of a Container in Flexbox - WP Beaches

CSS Flexbox Tutorial: Learn About CSS Flex With Flexbox Examples

CSS Flexbox Tutorial: Learn About CSS Flex With Flexbox Examples

How to align flexbox columns left and right using CSS ? - GeeksforGeeks

4. Flexbox Examples - Flexbox in CSS [Book]