Responsively size this CSS monstrosity?

Hey guys, I made this crystal last year and failed to make it 100% responsive. I hardcoded all the widths as percentages and not sure about the best way to go about this?

Here is the site (artistic nude paintings — some NSFW) so you can see what I’m talking about:

And here is the code:

I’m in the process of changing the margins over to absolute positioning, but not sure how I should do the widths? Maybe a calc(100% - x)?

i’d suggest slapping a nice NSFW on there!

Any ideas on this? I’m not sure the best way to go about it?