Stylesheet

You should be able to redownload the theme from here, and then you can reupload the stylesheet to your server.

Hello Watson,
When making changes to your themes css its best to either make a child theme or install a plugin that allows custom css such as the Jetpack Plugin. If you’d like to learn how to make a child theme(its really very easy) just click here https://codex.www.ads-software.com/Child_Themes

Making a child theme or installing a plugin guarantees you wont lose your original css code when working on it or by your themes next update.

And to fix your current predicament simply re install your theme or upload the stylesheet like Stephen said.

If you need anything else feel free to ask.

Thats great many thanks both, got it back to how it was. Yes ill make a child theme now, dont want to go through that again!

Thanks again!