CSS Property - Border Color
Initial: the value of the 'color' property
Applies to: all elements
Percentage values: N/A
The "border-color" property sets the color of the four borders. "border-color" can have from one to four values, and the values are set on the different sides like "border-width".
This property also applies to all of the following border colour elements:
If no color value is specified, the value of the "color" property of the element itself will take its place.
The following example will have a black solid border as it takes on the "color" property.
Using the following example you can specify all four border colours in one tag.
border-color: red blue black red;