The border-color Property

The color of the border can also be specified using RGB values:

A solid red border

A solid blue border

A solid grey border

The internal stylesheet embedded in the head of this page

<style>
p.one {
  border-style: solid;
  border-color: rgb(255, 0, 0); /* red */
}

p.two {
  border-style: solid;
  border-color: rgb(0, 0, 255); /* blue */
}

p.three {
  border-style: solid;
  border-color: rgb(187, 187, 187); /* grey */
}
</style>