3D Transformations are applied here in CSS3 to buttons in muscular fashion. But the CSS3 3D coding is truly long and garrulous [think error prone]. Thus the attraction of CSS preprocessors like LESS and SCSS.
So LESS available in the Codepen test environ was applied to the Buttons with a resulting drop from 182 lines of CSS to 157 in LESS. More important by using a LESS variable @colored we can change the color of the popup in one place – go into the CSS panel and change it and see all the colors in the panel change accordingly.