Round buttons are one of the components of Material Design, click to discover more...
Material Design Lite (MDL) is a library of components for web developers based on Google's Material Design Philosophy: "A visual language for our users that synthesizes the classic principles of good design with the innovation and possibility of technology and science." Understanding the goals and principles of Material Design is critical to the proper use of the Material Design Lite components.
Editing the CSS
Cut down the amount of code by removing unused classes from the unminified file then minify again.