Well, 4k is the size of the library after it’s been minified and gzipped. After running a fresh build of pure from their github repo, the base.css file which you’re importing and not referencing weighs in at 8.57k unminified/uncompressed.

If you were to reference that import, you’d see the bytes peel off, but I imagine you included that file in total because you wanted to get all those defaults.

If you’re not already crunching your compiled output down, try pasting it into here. Do you get better results? If you are, try turning it off and doing the same just to make sure there’s not something that can be further refined.