Failing Gridception

I have a grid, with grids inside. I cannot make it responsive. At all. In fact, strange FR units appear, that are different sizes to other FRs.

Maybe grid isn’t the right thing to be doing here. But I am determined to learn grid. And gridception.

Can you help me figure out how to change the grid(s) to work at different breakpoints?

Here is my site Read-Only:
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