Grey out areas when i select dates from a drop down

Hi I would really like your help.

The function is want is on one sheet you select a day and on the next it grey out that day. Iv changed it for the sheets to show what i want it to look like.

The test is what i want it to look like and the sheet i need doing is well, what i would like to add the function too.

So on team leader core hours you pick date in C16 and D16

I would like all the days so C16 has Monday and D16 has Wednesday on the Jan sheet to be greyed out.

So if they pick a new set of days it just greys out that day

hope this makes sense.

That's excellent thank you so much