twentyeleven theme: Where is the code that handles moving the search bar on resize?

The search field – #s – is floated to the right side, so the following content just moves down when the site is small enough. There are some adjustments to its position in @media blocks at the end of the stylesheet. For example this:

@media (max-width: 650px) {
    /* other stuff */
    /* Make sure the logo and search form don't collide */
    #branding #searchform {
        top: 1.625em !important;
    }
}