The column-rule-color CSS property sets the color of the rule between columns.
column-rule-color: value;
object.style.columnRuleColor = "value";
<'column-rule-color'> = <color>
<color>
Specifies the color using a keyword or a numerical specification.
currentcolor
column-rule
column-rule-style
column-rule-width
World Wide Web Consortium (W3C)