Align Items in CSS using Flexbox
https://pupli.net/2017/06/14/align-items-in-css-using-flexbox/
CSS flexbox float right
https://pupli.net/2017/07/13/css-flexbox-float-right/
How to make a div 100% height of the browser window
https://pupli.net/2019/05/18/how-to-make-a-div-100-height-of-the-browser-window/
Absolute Positioning Inside Relative Positioning
https://pupli.net/2019/06/14/absolute-positioning-inside-relative-positioning/