Can I use a field in an html tag?

I tried this formula in a text formula field, but the background color does not change when I use the text field called Calendar Color in the html tag. I don't get any syntax errors, but the background color doesn't change.  In this example, the Calendar Color field has a value of #0040ff.

"<div style=\"color:white;background-color:[Calendar Color];\"> " &[Calendar Color]& "<div>"

Please let me know if I'm missing something to use a field in an html tag, or if that's just not possible.