Configure theme (e.g. primary color?)

[cboettig]

Hi folks,

Loving jupyter-book (migrating here from quarto) but I am struggling to customize the theme, e.g. by setting the primary color. I've tried various ways I've seen suggested for doing this:

• custom css variables
• I've trying to add a custom _sass/theme.scss redefining $primary

but haven't had any luck overriding this.

It seems that some sphinx themes provide a mechanism to set colors in the conf.py; it would be great to be able to do something similar in jupyterbook configuration yaml or with a custom sass. (compare to quarto theming). I'm only familiar with how other static site generators have handled this, I'm not experienced enough in css, sass or sphinx to figure out how to alter the behavior here though!