Change sidebar width

How can I change the sidebar width?

http://136.144.206.149/~jdvdtol2019/referenties/

Thanks

Hello there,

You could easily achieve it with this simple CSS code:

    @media only screen and (min-width: 992px) {

      #primary.col-md-8 {
        width: 60%; 
      }
      
      #secondary.col-md-4 {
        width: 40%;   
      }
      
    }

Add it to Appearance > Customize > Additional CSS from dashboard.

Regards,
Kharis