Made an adaptive grid, what can be improved? What's wrong with her?

Question

css

I wrote just such a grid on flexbox.
I decided to make the names a multiple of the number of columns. That is, if you have 4 columns in your layout, then set the class .col-4 for each column. Well, under different permissions, I wrote different behavior of these same columns. So far 3 resolutions: >600, >1024, <1024
There is also the possibility of a percentage, for example, you need a block of 2/3 and a second block of 1/3. We put the classes .col70 and col30, and everything works (but they do not support adaptability).
What do you recommend adding? What do you think, is there any point in such a grid or are there simpler tools?
thanks for answers

Answer 1

Bootstrap is just the opposite. The benefits of this are only to confuse. Breakpoints are neither fish nor fowl. Virtually no flexibility.