A border is a line that surrounds an element, like a frame around a painting. Borders can be set with a specific width, style, and color:

• width—The thickness of the border. A border’s thickness can be set in pixels or with one of the following keywords: thin, medium, or thick.
• style—The design of the border. Web browsers can render any of 10 different styles. Some of these styles include: none, dotted, and solid.
• color—The color of the border. Web browsers can render colors using a few different formats, including 140 built-in color keywords.

p {
  border: 3px solid coral;
}

In the example above, the border has a width of 3 pixels, a style of solid, and a color of coral. All three properties are set in one line of code.

The default border is medium none color, where color is the current color of the element. If width, style, or color are not set in the CSS file, the web browser assigns the default value for that property.

p.content-header {
  height: 80px;
  width: 240px;
  border: solid coral;
}

In this example, the border style is set to solid and the color is set to coral. The width is not set, so it defaults to medium.