You can customize how your filesystem looks. The colours chosen here apply to the directory you're currently in and all files and directories in this directory. Colours which you do not want to modify can be left empty. Then the default theme colour will be used.

Button
Highlighted button
Danger button
Background
Body
Card
You can choose an image to show above or behind the files in this directory. The image will be picked from your filesystem. The image will get a shared file link. You can move and rename the file like normal, but if you remove the shared file property your branding will stop working.
Header image ID
Header image link
Background image ID

Below is an example of what the site looks like with these colours:

The background
The content body. A link!
The top layer, for highlighted things