When setting duplicate properties for a number of elements, CSS allows you to group those elements within your CSS Style Sheet or <style> section. You simply use commas to separate the elements in a single line.

For example, you wish that all of your heading tags are of a particular font and color.

h1 {color: #882200; font-family: 'Courier New',  monospace;}
h2 {color: #882200; font-family: 'Courier New',  monospace;}
h3 {color: #882200; font-family: 'Courier New',  monospace;}

The line below is equivalent to the three lines above:

h1, h2, h3 {color: #882200; font-family: 'Courier New', 'Courier New', monospace;}