How to get 'dn' to work for mobile devices with tachyons and preact

Question

I am using tachyons in preact to style my app but having problems with the 'dn' (display none). I am trying to get my header imagine not to display on mobile but it doesn't work. 'dn' does nothing. However, if I try 'dn-ns' (for display none - not small), it works. So I ought to be able to do the logical opposite of that but nothing so far has worked.

Here's the component I'm trying to style. Any thoughts? I have tried every combination I could think of and looked around for anything that might be overriding to no avail.

import { ReactComponent as UMLogo } from '../assets/umlogo.svg'

import seaGif from '../assets/images/Sea.gif'

const Header = () => { return(

)

}

export default Header;