Changing the underline color of a hyperlink cannot be done with straight HTML. To do this, we take the regular hyperlink code and add an inline CSS style to it. The underline first has to be removed with the text-decoration property value of none and then we add the border-bottom property with 3 short-hand CSS values of 1px solid #999999.
1px = Variable border width in pixels which in this case is used as the hyperlink underline width. solid = Border style. #999999 = Color code. Use this variable to change the underline color. Replace this value with your choice of color codes.