Responsive login being responsive at wrong browser width

I've got a tough one here. I have (quite literally) been pulling my hair out over this for the past week. I finally broke down and decided to ask for help here. I even learned how to use EGit so I could get the project up on Github if anyone cares enough to try navigating that maze to find where my problem is.

Following along with the code used in Vaadin's recent Best Practices webinar, I tried integrating it into the web app I am creating. At the same time, however, I am attempting to using the nice, responsive version of the Dashboard demo's login page. (I like it much better.)

The problem I'm running into is that the login panel resizes when the browser is reduced to about 500px wide instead of the 800px that it's supposed to do. I do not know why this is happening and was hoping someone might have some ideas for me to try. Barring that, if someone really doesn't mind trying to run my code and navigating the myriad of files to find the culprit, it's available. I do hope someone can help me with this.

Thanks.

Now it has gotten worse.

It's been a few months since I've had an opportunity to work on this app. I started up Eclipse, updated it, updated the Vaadin plug-in via ivy.xml to 7.6.1, and gave it a test run. I got the login screen, as expected, but when I adjusted the browser width to less than 800px, Chrome gives me the "Aw, Snap!" error message. What possibly could have changed in the last few months to break my responsive design!?