Excel - Basic project planner

Dear Experts,

Could you please have a look on the attached Excel file,

BasicProjectPlanner.xlsx BasicProjectPlanner.xlsx

basically would like to have a basic project planner.

Briefly there is a kind of control sheet in columns A-B with defining when the project starts as 'Starting week', while there are three phases 'Design', 'Validation', 'Execution' with a number that how many weeks they need to complete:


The target would be what can be seen in columns I-AH with colors,so depending on the numbers in column B, that many cells should be colored by Excel with some automatic logic:

Just an example to see the logic, so if the 'Starting week' would be 12, the 'Design' 2, 'Validation' 3 and 'Execution' 4, then the timeline should be a following:


Being not sure technically how that could be executed, in some other files have seen that such solutions are often based on Name manager and Conditional formatting (of course welcoming any suggestion, except macros as would like to avoid the use of them in this case)

Thanks in advance,