Update to 2.0 lost custom.css - problem with footer and social icons

Hello guys,
today I updated to version 2.0 and now my social Icons are gone and my footer looks weird, There stands: “Fatal error:…” I used a child theme and wanted to check for the custom.css. So I searched for theme options but I can not find it. Did they change something within wordpress because I can not find theme options and custom css now. That is the first problem. So it seems like my customization of the footer is lost. But also how can I get back to that and at least get my custom.css back. Also, when I would go to look at my site, while logged in, there were always above the header a menu with option, like “Modify Post/Page” or something like that and this entire menu is gone. I do not know what happened.

Hope someone can help me.

Thanks

EDIT: So I figured it out with the social icons but there is still one problem. It recognized the Facebook and Twitter links but the Google+ one is just a blank icon what can I do there?
Also I would still like to have the custom.css back because I would atleast like to know the color I used for the icons.

Also I found the text I had written for the footer in the same customization menu but there still seems to be a problem.
Right now there is the following when looking at my site in the footer:
Fatal error: Call to undefined function sparkling_social() in /www/htdocs/w013175f/xn–bcherdiemanlesenmuss-pec.de/wp-content/themes/Sparkling-Child/footer.php on line 25

Hi @dssl,

I hope you are well today and thanks for posting here.

Regarding custom CSS option, all theme options are now moved to WordPress customizer that you can find in the admin area under Appearance >> Customize. All settings are still there but now you can tweak everything on a live preview.

The Google+ icon is getting displayed for me using the Google plus URL like https://plus.google.com/+Freewptp in the custom URL menu item.

Please try using this URL and let me know whether it works for you or not.

If it doesn’t work for you then please share your site URL where it doesn’t work so that i can troubleshoot it.

The fatal error ‘Call to undefined function sparkling_social’ is resolved in the latest released version of Sparkling theme so please try updating your theme to the latest version.

Best Regards,
Movin

Right everything works now. The one thing that I just cannot get is, how to change each social icon color individually. I can only change it to one color for every icon.