Simple button hover and click animation
Tutorial by Mirko Zovko | 14. Mar. 2019.
The most important thing in style is to add to btn class width, height, display block, and transition. After that add display block to both of <span> elements and add them transition too, and put them with style float next to each other. After we hover btn element we need to move away first <span>element and give full width to second <span> element.