[recursivecaveat]

Imagine the universe as a giant balloon. Inside are little miniature balloon stars floating around, tied with string into balloon galaxies. If we heat the air: the big balloon expands, the clusters of mini-balloons spread out from the other clusters, but the clusters don't get any more diffuse. The string is way way too strong to be overpowered by the separating force from the expansion of the gas over short distances.

[Razengan]

I mean, this is tricky to even ask: is there still expansion INSIDE galaxies, BUT it's countered by gravity?

Or is there no expansion within galaxies at all?

i.e. is dark energy or whatever that causes expansion only present in the absence of matter, or is it present everywhere regardless of matter, but because matter also has its own gravity the expansion is not visible/relevant?