Most themes, especially dark ones, have very high-contrast which makes them tiring for the eyes. Squirrelsong themes are low-contrast but still provide enough color and style variety to distinguish various elements of the code and avoid long chains of code printed in the same style.
big applause for sticking to your vision for seven years and then refining it! 🙌 I get what you mean about the bright themes being a tad distracting. Quick Q: Have you considered or maybe even developed a version that's tailored for video editing software UIs? That would be such a neat addition for us video creators.