Add banner stretched across header

[Greek76]

I'm trying to make my banner stretch across the whole forum but its not working with the code I'm adding. Can someone point out what I'm doing wrong? Thanks!

<!-- logo -->
<a name="top"></a>
<table border="0" width="$stylevar[outertablewidth]" cellpadding="0" cellspacing="0" align="center">
<td align="left"><a href="https://www.example.com/forum/forum.php"/><img src="/index/we3.gif" border="0" width="100%"/></a></td>
</td>
</tr>
</table>
<div class="above_body"> <!-- closing tag is in template navbar -->
<div id="header" class="floatcontainer doc_header">

<!-- content table -->

--------------- Added [DATE]1602274406[/DATE] at [TIME]1602274406[/TIME] ---------------

Wow this forum really is dead.. What a shame. It used to be so busy.