In contrast to the outline, the element's borders can each be of different widths. The border width can take a predefined value — thin, medium, or thick — or a more specific one using pixels (px), points (pt), centimeters (cm), or ems, like in the example.

You can specify the property in 3 ways:

• Using the border shorthand property and setting the same width for all sides
• Using the border-width shorthand property and setting the same or various widths for each side
• Using individual properties for each side (border-bottom-width, border-left-width, border-right-width, and border-top-width)