Highlight cells in calendar based on date ranges in another table

After selecting B3 in the calendar, use this formula to create your conditional formatting, select the color of your choice.
=--(MEDIAN(B$2,OFFSET(PODACI!$B$1:$C$1, MATCH($A3, PODACI!$A:$A, 0)-1, , , ))=B$2)

Also, while B3 is selected you should also click on VIEW > FREEZE PANES > FREEZE. This will lock your headers in row 1 and your IDs in column A so they are always onscreen as you scroll.

Ah, I just noticed you have MULTIPLE entries for each ID in the data sheet. So this wont' work. You would have evaluate EVERY row of the data sheet for every individual cell of your calendar. That's 28k calculations PER CELL on your calendar. There are 3736650 cells in your calendar. That's 104 trillion calculations.

This is not a formula project. That will kill your workbook. You would need a macro that can go through each cell in your calendar ONE TIME and check the values in your data sheet to determine if the cell should be colored or not.

Can you explain the value of a sheet as large as your calendar? It cannot be viewed or even reviewed in any efficient manner.