How to correctly set classes in BEM?

Question

css

Please help me figure it out, I would be very grateful. There is a specific question below , but in general, tell me where the errors are . at the bottom there are links to snippets of code + made a schematic ... open the picture with the right mouse button in a new window (it is large)
b- this is a block
l- this is a layout
here html
here css excerpt
the point is that I set a modifier to the block and through the block I have to use inheritance to reach the children, on the one hand it’s not right but on the other hand, I don’t want to assign another class to each children ... how to be all the same?