Thanks for such a quick response, guys. I wasn't familiar with "responsive design" so thanks for filling me in on that. I'm hesitant just yet to try alienneila's advice until I verify with you a couple of things.
Does TwentyEleven always stretch the sidebar across the content area when it's minimized? Because if not, if possible I'd like to fix whatever I did wrong in the child css instead of putting more code in.
Could I bother you to take a peek at my child theme's CSS?
I hope I'm doing this right; I've just created a pastebin account. Here is the child's style.css, as you'll see, I've borrowed code to make a second side-bar, added a featured slider, and dropped my entire page down so the background is the header. It's all well labeled: