The border-color Property

The border-color property can have from one to four values (for the top border, right border, bottom border, and the left border):

A solid multicolor border

The internal stylesheet embedded in the head of this page

<style>
p.one {
  border-style: solid;
  border-color: red green blue yellow; /* red top, green right, blue bottom and yellow left */
}
</style>