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 as for 'border-width' above.

If no color value is specified, the value of the 'color' property of the element itself will take its place:

      P { 
      color: black; 
      background: white; 
      border: solid;
      }
      

In the above example, the border will be a solid black line.