A simple but effective micro-interaction design for download buttons by Aaron Iker. When you click on one of the download buttons the down icon , the down line jumps up and pulls down a progress indicator kinda like pulling down a shutter and the download icon changes to a tick mark and the download text changes to open file.
If you are having trouble with the pen, try the archived copy on GitHub
See the Pen
Download Button Animation by Aaron Iker (@aaroniker)