hovering on text does not show the description properly

Hi everyone,

In sharepoint I am showing the list of titles and on hover it should show me the description. But somehow with my css i cannot see the description properly.

Please find the image on the top and the css below.

CSS:

<style>

span.s开发者_如何学Pythonummary {
        position: relative;
BACKGROUND: none transparent scroll repeat 0% 0%;
}

.ms-vb span.summary a {
background-color: #DFDFDF;
}

span.summary a span {
        display: none;
}

span.summary a:hover {
        font-size: 100%;
        font-color: #000000;
}

span.summary a:hover span { 
        display: block; 
        position: absolute; 
        margin-top: 10px; 
        margin-left: -10px; 
    width: 275px; padding: 5px; 
        z-index: 900; 
        color: #001A49; 
        background:  #DFDFDF; 
        font: 12px "Helvetica";
        text-align: left; 
        text-decoration: none;
}

.ms-alternating .ms-vb {
background-color:  #DFDFDF;
}
</style>

Try the solution provided in below link Getting :hover to Work in IE7

If this does not work as well you would to apply IE hack script for hover which is readily available over net