Responsive Tip Calculator built with Semantic HTML, Nested CSS & JS

I have gone a little off the path here. I decided to rework my html to adjust the flow of the UI. I have changed it so the user first inputs the bill total, selects the number of people, and then adds the tip amount. I find that it makes more sense, rather than the original design. I have also made to overall design smaller, to create a compact, sharper looking UI.