Conditional Formatting Dates

Hello,

I'm looking to do the following & I have not found a post or instruction on how to accomplish this task.

I have a 3 Col (A, B, C) Task Description, Target Date, Completion Date.

If no date in Col C, & the date in Col B is 3 weekdays or less than today. Format Red. If there is a date in Col C. Format Gray
If no date in Col C, & the date in Col B is between 4-7 weekdays less than today. Format Amber. If there is a date in Col C. Format Gray
If no date in Col C, & the date in Col B is greater than 7 weekdays less than today. Format Green. If there is a date in Col C. Format Gray

I have attached a simple workbook if that helps.

Thank you.