I've set the default theme to Mayo which I think is the one most like the previous theme. If you go to your User Account you can select this theme and the color scheme you wish to use. Please test them out and find one which suits you best.
There have been some comments about font. I will make it so that you can select between serif and non serif and apply bigger font.
If you have feedback on other aspects of the site, please be specific about what the problem is and exactly where to find it.