A family of Microsoft relational database management systems designed for ease of use.
I'm afraid you can't implement conditional formatting this way, because in a continuous form, when you change the properties of a control you change them for all instances of that control, in all the rows displayed on the form. Only true conditional formatting, as understood by Access, will allow format properties to vary from row to row, and then only the set of properties that are supported. Through some trickery, you can usually *hide* a control conditionally, but I don't know a way to do what you're looking for.
That doesn't rule out the possibility that someone has found a cunning workaround, and I'll take a moment to look for one, but I don't hold out much hope.