Simple Parametric Theme aims to change the colors of the default dark theme with minimal modifications. Pre-set colors are roughly based on Google.com, but you can change them to whatever you like!
You can edit the following variables to change the colors of the theme.
--primary-hue: 220;
--bg-saturation: 7%;
--bg-lightness: 13%;
--secondary-hue: 216;
--link-saturation: 87%;
--link-lightness: 75%;
This theme was put together hastily and I don't plan to maintain it actively, but I hope you find it useful. Pull-requests very welcome.