The border-right-color property is used in CSS and certain HTML elements. This property controls the color of the right side of the border of an element's rendering box. If no border-color is specified for an element's border, the value of the color property is used instead. To specify the border color for all the sides, use border-color. To specify the border color for the other three sides, use border-top-color, border-bottom-color, and border-left-color.