Formatting for Mobile

I created an email that is done in HTML. The recipients will receive on desktop and mobile. I cannot use embedded CSS to style it because the email program does not support it so I am stuck using inline CSS. The desktop version looks great, but on mobile it looks awful. I used percentages for the images and widths hoping that would help, but there must be something I am missing. Could someone help please? Thank you.
center-div.html