Styles customizer doesn't work properly

Hi,
I was playing around with one of my styles (I changed the font size from 17px to 1.1em and the line hight). When I saved itI got an error message and the customizer shut down and I was back to the "Templates: Edit Style" page. Whe I reopened the customizer I got an error message and could not access this particular style anymore. The page still works.
How do I get the style back?

Greetings
Thomas

www.gabineurohr.com

Hi there,
sorry I dont know what happend.
Please save your customized css and styles and reinstall the theme.
yootheme.com/support/question/75099

Hello,
I'm not sure I understand what you mean. How should I reinstall the theme so that all my content, articles, modules stay the same?
Maybe all my problems with custom css not working (see my other topics) is related to this problem?