When it comes to styling the border of an element on a web page, the CSS border-color property is one of the most commonly used properties. The border-color property allows you to specify the color of the border of an element.

The border-color property can be used to set the color of all four sides of an element’s border at once. To do this, you would use the following syntax:

border-color: red;

This would set the color of all four sides of the element’s border to red.

If you want to set the color of each side of an element’s border individually, you can use the following syntax:

border-top-color: red;
border-right-color: green;
border-bottom-color: blue;
border-left-color: purple;

This would set the top side of the element’s border to red, the right side to green, the bottom side to blue, and the left side to purple.