You do not tell where you want to change the color. The solution is sometimes a bit hidden away, but there are plenty of possibilities and combinations, such as:
First you can change the color for the whole website:
Left general menu: Settings: Website UI: Right Tab Color
Set the color per page:
On page left menu: click on gear next to sitePad logo; Close default
open Body and Props tab: on Custom Header Footer Code: Add CSS code in
Header Code input field
In Rich Text widget:
Click on </> button and add CSS style code
In Embed widget:
Add CSS style code
As In-Line CSS:
In for example Title widget.
In a widget itself:
Under Settings or Options menu
With a search like:
Quote
html inline css
you can find enough examples for an inline CSS assignment.