Resizing youtube window on smartphones

Hey guys, I got my wordpress site up and running successfully. The ease is absolutely amazing, you can go by without even knowing any html! I noticed the site even displays great for smartphones (twenty eleven theme) without any extra work needed. One thing however is when I posted something with a youtube link, it embedded automatically which is awesome. However when viewed on the smartphone it distorts the width and makes the embedded video go through the design.

Any tips on what I could do to prevent this? Thanks!