Marketo's mobile styles are actually not very pretty. Does anyone have the CSS to override them? I just want to unset all CSS for max 240px widths.
It you are talking about email, you should probably try to get your own template. You may want to use services from Knak.io or hoosh marketing.
If it's about landing pages, are you using a guided LP or an free-form ? If you are using a guided, you can also have your own one being developped. If you are using a free-form, you should consider moving to a guided one, that will provide all flexibility you need on mobile design.
See Guided Landing Page Templates - Marketo Docs - Product Docs the library of guided LP's from Marketo.