Thanks for the heads up re: margin capitalization.
The testing code I used above I sent from Litmus. The emails I usually code I test by sending via Litmus, Responsys, and Silverpop. We add tracking codes for our sends, but the code above did it without any of our tracking pixels on it. I don't know if Litmus adds tracking pixels when I send from Builder.
You're right. When I send tests from putsmail I don't see the pop.
The styles for font-size and text-alignment for the navigation are on the <p> but the class to change them is on the <td>. Move the class to the <p>.
Also, you've got semi-colons before the !important in the .responsive-text class in the style section.
We figured something out. If anyone is having a similar problem, here's our solution:
We added a <span style="display: none; visibility: hidden; font-size: 0; line-height: 0;"> </span> after the @ to disrupt it.