Help with Traffic Light SharePoint Calculated Formula

I am wanting to create a column called “Traffic Light” on an existing SharePoint Library.

Column Name = Traffic Light

Data Type = Single line of text

Formula:

="<DIV style='font-weight:bold; font-size:24px; color:"&IF([Review Status]="Approaching","Green",IF([Review Status]="OverDue,"Red","Yellow"))&";'>•</DIV>" 

Despite my best endeavors I can’t seem to get the correct syntax for this formula.

Help needed please.