I accidentally changed something in the style.css source code and am now getting an error. Is it possible to get a copy of the original source code to get my website back up?

Try downloading the theme from this site, and you should be able to use the downloaded style.css that is included. I am assuming you installed the theme through WordPress last time.

Hello there,

You can get it here on WordPress theme repository. Please don’t do code modification on the main theme’s files. Use a child theme instead, please. We have a premade child theme for Sydney already which can be downladed from here.