[Twentyeleven] Changing search bar color

[ Moderator note: please use backticks or the code button for code snippets instead of blockquote. ]

#branding .only-search #s {
background-color: #666;
border-color: #000;
color: #222;
}

style.css line 659

I’ve not checked the CSS but more precisely with a child theme, place that new CSS in your child theme’s wp-content/themes/child/style.cssstyle.css file.

Don’t edit the parent’s style.css file.