Working with a Div Overlay, Positioning (w. picture&codes) Options

[lovelyfatale]

I just started making a new Div Overlay.. And I'm trying to re-position this table so it's in the dead center of the page. Here's what it looks like NOW:


And here are my codes so far...
ABOUT ME:

CODE

<hide comments/friends>
<style type="text/css">.comments {visibility:hidden;display:none;}</style>

<style type="text/css">
.Main { position:absolute; left:50%; top:125px; width:800px; z-index:1; margin-left:-400px; padding:0px; border:0px; background-color:transparent;}
</style>

<style>
.content{
width:300px;
float:left;
padding:5px 5px 5px 7px;
margin:5px 0 0 5px;
border:3px solid;
}
</style>

I'D LIKE TO MEET:

CODE

<DIV class="Main"> <table style="width:800px; height:800px; cellpadding:0px; cellspacing:0px; border:2px solid silver; background-color:ffffff;}"> <tr> <td valign="top"><table style="width:300px; height:300px; cellpadding:0px; cellspacing:0px; border:2px solid black; background-color:cccccc;}"> <tr> <td valign="middle">UNDER CONSTRUCTION.</td> </tr> </table> </DIV>