A Heading in Green

Just some text here. This bit is emphasized.

A Nested list

  1. Breakfast
    1. Cereal
    2. Toast
    3. Coffee
  2. Lunch
  3. Dinner

This gives you a basic idea of how to use style sheets and how they "cascade". There are a great many elements of style that can be specified with style sheets. Niederst's Web Design in a Nutshell is a good place to start to learn more about what you can do.