More atractive design will be fine (avoid white background) + add some trendy colors: http://colorhunt.co/

Thanks sazers - did you try the different 'Themes' and 'Palettes'? You can toggle through them via the 'Settings' dropdown on top of the page.

Also, do you have any favourites on colorhunt.co?

playok.com might be a good reference. it has all the bases covered and a great balance between simplicity and features, plus an active community. I played your othello bot and it was really easy, maybe you could use some of the open source othello programs like edax to make a more challenging computer? http://abulmo.perso.neuf.fr/edax/4.3/index.htm

Thanks okwme -- I'll check out Edax!

I personally only play chess online against humans. It looks like you can only play against computers. Is there a way to play against other people?

Definitely reefoctopus - if there are other players online, you can challenge them or simply create a match with no bots and allow others to join