Help - Conditional Formatting

Condition 1 - If cell K is not blank:

1) cell A should show how many days diference from expiration date (cell B) to today
2) If between 95 - 91 color of Cell A should be green
3) If 90th day - color red
4) If cell P (dispatch Date) is not empty ie any date is shown the above 3 condition should not be satisfied

Condition 2 - If cell K is blank:

1) cell A should show how many days diference from expiration date (cell B) to today
2) If between 76 - 80 color of Cell A should be Blue
3) If 75th day - color Yellow
4) If cell P (dispatch Date) is not empty i.e. any date is shown the above 3 condition should not be satisfied


Thanks in advance for your help.