Bourbon

By default your stylesheets include Bourbon. This css library gives you lots of useful functionality that you’d otherwise have to write by hand. Read up on this library and get instant rounded corners across all browsers, typography features, reset, and much much more. As just one simple example

CSS

section {
  @includelinear-gradient(totop,red,orange);
}

will give you the following output

CSS

section {
  background-color:red;
  background-image:-webkit-linear-gradient(bottom,red,orange);
  background-image:linear-gradient(totop,red,orange);
}

without having to remember to put Opera, webkit, Mozilla and html5 elements into your css. You don’t need to use bourbon, but it can help you keep your site consistent across browsers more easily and save you time with common css blocks.

Read the docs for Bourbon.