Choosing colors for a new Squarespace site challenges me. There are 16+ million colors to choose from, times the number of elements in the Style Editor that I'm able to colorize. That's some scary math right there, and it helps a lot to reduce my options.
Drawing from Preexisting Artwork
Figures 1 and 2 show recent sites that I've stood up on Squarespace, and I'm pretty happy with their color schemes. Figure 1 is the "easy" case, a redesign for a cycling club's website. There was a logo in play that had been designed by a professional graphic artist. She'd done a good job in choosing colors, and all the club members were more than happy her work.