Hi @mano,
You can edit the obsidian.css
file in the root of your Vault.
Each Vault has a different css file, and every time you select a new theme, this file is replaced.
I use Sublime Text with a few add-ons for previewing color codes, and picking new colors.
I think this is the section that needs changed to replace the monospace font:
.markdown-source-view {
font-family: 'roboto mono', monospace;
color: white;
}
If you screw up the template, just change the theme back to Red Graphite to get the original file back. And once you have the edited version the way you want, be sure to make a backup so you don’t lose it next time the theme is changed!