This is an adaptation of Sarah Drasner's Night Owl theme for Roam Research.
- Create a new page called roam/css. It has to be that name exactly.
- Enter some text in one block, this could be used as the name of the theme
- Add another block and indent it, add a code block here using
/code block
- Paste the styles from roam.css
- Set the code block language to
css
in the top right
The graph should now be using the Night Owl theme! There is also this video which describes how to setup a theme.