As mentioned in the logo thread, I'm not too happy with the secondary colour of the dark theme. I think it is too close to the main colour and the hue too green. When viewing the main page on PC, the secondary headers are not visible, only the menu in the upper left corner. The slightly different colour than the three big main headings made me think the menu colour is a mistake and should be the same as the primary colour.
I think there are two options: use the same colour for both, primary and secondary headings or make the secondary colour more distinct.
Btw, I can easily change the colour of the logo - if necessary, we could even have different colours for light and dark theme.