tansparent background affecting color of text

tansparent background affecting color of text

I have a box with transparent background color, below is the CSS & HTML
CSS
#box{color:black; text-align:center; margin:50px auto;
background:blue; opacity:0.1; border-radius:11px;
box-shadow:1px 1px 1px #656565; padding:20px; font-size:25px; }
HTML
<div id="box" class="center">
I need this text to be black.
</div>
Or you can see online demo http://jsfiddle.net/jrmXh/
As you can see, the color of the text despite being black is not being
show, and I would like to know why this is happening, and how to fix it.
thanks