Splunk 8 UI Themes

[shocko]

Guys, loving the dark theme built-in option in Splunk 8. I was wondering though if this can be extended or modified? Say I want to change a font color:

• Is there a CSS file I can edit?
• If so is that global CSS file or per app (i.e. when you select Dark Theme for an app/dashboard does it copy a CSS file into the app folder or the like) ?

Beyond that is there a reference to create one's own themes?

[efavreau]

@shocko 
I love the question. The answers are complicated.  I'll respond below for Simple XML Dashboards. For Dashboard Studio, please submit a different and detailed question to the Splunk Community.

1) themes out of the box are light and dark. You can look through the docs on how to create your own, if you wish: https://dev.splunk.com/enterprise/docs/developapps/createapps/buildapps/adduithemes/
2) If you search your Splunk filesystem for bootstrap-dark.css, you'll find the file that provides dark theme.
2.5) If you don't have access to the filesystem, you can use your browser dev tools to get the URL to bootstrap-dark.css.
2.7) Be warned. It's a BIG file. Formatted pretty, it comes to >7300 lines
3) You're better off to change the font, IMHO, to use CSS overrides. To read more:
https://docs.splunk.com/Documentation/Splunk/latest/AdvancedDev/UseCSS
https://docs.splunk.com/Documentation/Splunk/9.1.2/Viz/PanelreferenceforSimplifiedXML

Finally, note in that last example, you can include css style inside an HTML panel within a dashboard. Searching through this larger Splunk Answers Community for "html css style dashboard panel", should yield you plenty of examples.
Here's a great one from my friend Niket to get you started with nearly ready copy/paste code: https://community.splunk.com/t5/Dashboards-Visualizations/How-to-add-style-to-panel-titles-in-my-das...