Font Family for email on Outlook Windows not applying

I know this has been asked everywhere online and I've exhausted most of the solutions I've come across. I am trying to set the font-family on all of the elements within the body of an email.

It works across everything fine (Outlook Mac, Gmail, Yahoo) using this CSS:

<style>
    body, table, td {font-family: Arial, Helvetica, sans-serif !important;}
</style>

but not on Outlook Windows...

I tried to set the font-family inline on every single element in my email like the snippet below and it's still reverting to Times New Roman. Any advice on this would be much appreciated.

<h2><span style="font-family: arial, helvetica, sans-serif;">EMAIL HEADING TEXT&nbsp;GOES HERE</span></h2>

Many thanks.