border shorthands

In most cases you want to define several border properties (border-width, border-style and border-color) for all sides of an element.

Instead of writing:

border-width: 1px;
border-style: solid;
border-color: #000;

You can simply write:

border: 1px solid #000;

These shorthands are also available for every side of an element: border-top, border-left, border-right and border-bottom. So you can do:

border-top: 2px double #aaaaaa;