So, I took the suggestion of a comment writer, and Connect! now supports themes.
Of course, at this point the themes consist of the original color scheme, and now a new, totally pink and purple theme called “lovey-dovey”!
Yay! Lovey-Dovey!
Later I can always put in all sorts of other themes, now that the support is there.
As far as what sort of value this adds… it actually allows me to address the color-blind issue, by handling it with themes.
I’m also starting to notice the creeping complexity and size of the UI buttons on the side. When I first wrote the game, I wrote it with no buttons at all, and to start a new game, you actually had to refresh the page. It also had zeros in nodes with no connections. It also had all black nodes and connections.
Actually, blogging the development of this game has been pretty cool. Already I can look back (a whole week and a half) and see the various permutations it has gone through. It goes to show that even a game as simple as Connect! goes through a refining process.
And now that there are more than two colors on the board, it is really getting to be time to put in some instructions. I think I need to do that before anything else.
The Grumpy GameDev 
Nice work 🙂