How to hide "All" category in Flatiron Template

Site URL: https://danielhaskett.com/shop

Hi there

I am looking to remove the "All" category in my shop, so that I only have the categories that I have created. 

Can someone help me with the Custom CSS for this in Flatiron?

Thanks

Daniel

Add to Home > Design > custom CSS

li.active-link.all {
    display: none !important;
}