Hello,

In order to change the height of the divider, please change the row height and the divider would be 100% height. https://xtemos.com/docs/woodmart/header-builder/header-rows-columns-configuration/

If the color does not change try this CSS:

body .whb-color-light .whb-divider-element:before {
    border-color: red;
}

Best Regards