The border-color property works just like all the other color properties:
But just for the sake of completeness, here's the syntax:
| Property | Value Type | Example | Result |
| border-color: | color name | red | Border set to the named color |
| border-color: | hex value | #ffffff | Border set to the specified color |
| border-color: | rgb() value | rgb(10%, 80%, 0) | Border set to the specified color |