Hi,

You want to make header white or whole website?

If 2nd answer, please use below Custom CSS

body.site {
  background-color: white;
  color: black; }

I'd like to have the original themist backround color as i can see it here: https://www.joomshaper.com/joomla-templates/themis however it's not working on my xampp.

How can I upload a picture here?

How can I upload a picture here? For example using:

• https://imgbb.com/
• https://postimages.org/
• Or your own hosting

Support doesn't include help on Xampp, I can help only if you have site on server where we can logging and check etc. Support Policy rules!

I can understand this. I'm going to upload the website soon, so if you have any tips for now, please help.