Any way to add colour to DT3 groups etc

I prefer the look of DT2, with blue coloured groups, a red delete icon, blue Info icon etc etc.
I find DT3 very bland with all the greys. Is there any way to get the coloured icons etc DT2 had? I know I can change the icon for a group, however I don’t want to have to do this for every group.
I tried changing the preferences - labels to classic etc, but but doesn’t seem to do anything.

You can actually change the icon of multiple selected groups via the Info inspector/popover.

Can you expand a little upon this please? Are you saying that we can change more than one folder icon in the Navigation sidebar at a time?

Also, I notice that when in Widescreen view, the second navigation pane shows all groups (and the inbox) in colour. Can you add a preference to replicate this in the Navigation pane, and thereby save those of us who prefer to add some colour as a visual aid from having to do it all manually? The current look of the Navigation pane is so very dull.

Not in the sidebar (as it doesn’t support multiple selections yet) but by selecting multiple groups in the view and changing the icon in the Info inspector/popover. This might also be of useful for you: Can we color the project icon?

Thank you, yes, I have seen (and taken advantage of) @valente’s lovely work. I was looking for a preference to save me having to reverse engineer the look of previous databases, and also to have to manually change each icon in future databases.