50% Opaque background for entries? Options

[willum89]

I wanna know how you can make the background color for entries 50% opaque so that you can still see the image in the background. I tried

<style type="text/css">table.blogbody {
/* this edits the other the place where the blog is */
border: 1px dashed #FF8080;
background-color: #990000;
filter:alpha(opacity=50%);}
</style>

but it also makes the text semi-transparent and I only want the background transparent so how do i do that?