Time sheet

Hello,
This is quite complicated to explain, therefore, I hope I don't confuse you. I am doing out timesheets. The criteria is as follows:

Time period: 07:00hrs to 22:00hrs, employee will be paid single rate hour i.e. if he/she works 8 hours, its 8 hours x 1 pay

Time period: 22:00hrs to 07:00hrs, employee will be paid double rate hour i.e. if he/she works 8 hours between these times, its 8 hours x 2 pay

Any ideas how to work this out

Cell C4 contains the start time of work and cell D4 contains the finish time of work.
If C4 = 21:00hrs, and D4 = 23:30hrs then the total time worked is 2hrs 30mins, however, the time after 22:00hrs is considered double time so this means the employee will get 4hours pay.

Could you help me out with doing an if function in excel?

Thanks, Karl