Display thumbnail beside title of posts in scroll

I really like your plugin. But how can i show thumbnail beside title of posts in scroll?
I see: Please select if you want to display post’s thumbnail.
You may add a CSS rule to class vsrp_thumb to style the thumbnails
by default the size is same as post title’s height

I write the code as follows .vsrp_thumb{ in CSS :
float: left;
margin-right: 12px;
padding-top: 4px;
width: 65px;
height: 65px;
But do not run. Please help me!