The new theme is called “Inanis Glass”. You can change the background by clicking on the little bubble at the left end of the bottom of the page, and selecting the background from the list. The last time I tried this type of thing, several features of wordcurrents stopped working. I hope for better luck this time.
Note December 28: I had a problem, but Inanis, the theme designer helped me figure out that the problem was actually in the WordPress software, not in the theme.
Note December 24, 2018 For some years, the theme has been Twenty-Ten, a stock WordPress theme.