Maybe I am late on this...
Media Queries are out.
Thanks! price wise it seems similar to hubspot basic plan but at least they have a lot more contact slots so Ill look into this.
I notice this as well espescially if the email account is not from outlook.com/hotmail.com
I tested this email which I design and built and sent a test to my personel hotmail account and the other to my company office 365 account and it seems the 365 account absolutely does not support any responsiveness at all while the hotmail.com account works fine still
Office 365 (no responsiveness)
hotmail account (responsive)
No idea why is outlook doing this it was rendering responsive perfect before on android on both accounts.
The native email client for samsung s4 i remember I had two email accounts one for work which was an Exchange server and another just normal smtp. All i know the exchange email account just did not support the responsive at all while my SMTP rendered just fine on the native app.
And i sent your email a direct test to my samsung s4 native client SMTP email and it shows the responsive working fine. See the screenshot
So I am guessing it could be the exchange server that is probably removing the media querie or soemthing.