Define Several Items at Once.

For example, to display all the headings from <h1> to <h4> in a sans-serif font you could enter four separate lines, or you could group them together on one line like this:

This: h1 {font-family:sans-serif} h2 {font-family:sans-serif} h3 {font-family:sans-serif} h4 {font-family:sans-serif}

is the same as this: h1,h2,h3,h4 {font-family:sans-serif}