https://stackoverflow.com/questions/33451683/pen-highlighter-effect-in-css
https://www.lynda.com/CSS-tutorials/Adding-Font-Awesome-your-project/372808/413151-4.html
https://stackoverflow.com/questions/6382023/changing-the-color-of-an-hr-element
https://stackoverflow.com/questions/19254411/how-do-i-set-vertical-space-between-list-items
https://www.w3schools.com/cssref/pr_dim_line-height.asp
http://flexboxgrid.com/