Inspired by watching this Kevin Powell video about trigonometry in CSS, I made this pure-CSS orrery. (There's Sass here, does that still count as pure CSS? There's certainly no JavaScript). Also, I've now refined all of the trig out of it
In order to fit this on the screen in a way that makes any kind of sense, some scaling choices have had to be made:
1vw
There are some further shenanigans for the moons[2]: on top of the scalings above, we also apply a weighting to each metric:
In addition, the Sun's radius is scaled by 3x106km to 1vw, putting it completely out-of-whack with everything else