Do any one know how to use make colour component in block section?

I want to use custom color in the block section I found a make color component but I can’t understand how to use it.

Can we use transparent colour in block section… as we do in design section for layout etc.
Eg: colour optical 10% and 90 transparent.

I found this old reply from Thunkable community. I think it’s still working

That was explained in the doc i gave you. How to use a fourth value for transparent,