new background color for blockquotes

Please help. I’m new to WP. I’m using the theme Simple Style 1.10.1 by TemplateLite.com. I want my blockquotes to have a different background color from the rest of each post. My theme came like this:

blockquote {
clear: left;
text-align: justify;
padding: 0px 0px 0px 10px;
margin: 20px 20px 10px 20px;
border-left: 2px solid #666666;
}

I tried changing it to this:

blockquote {
background: #E8E8E8;
clear: left;
text-align: justify;
padding: 0px 0px 0px 10px;
margin: 20px 20px 10px 20px;
border-left: 2px solid #52665F;
}

I tried it again after deleting the “clear: left;” and switching a couple other things around, but nothing has changed the background color.

Any ideas?