I thought you wanted to change the background where the usernames are listed?
HTML Code:
<td class="alt1" style="background-color: yellow" width="100%">
<div class="smallfont">
<div style="white-space: nowrap"><phrase 1="$recordusers" 2="$recorddate" 3="$recordtime">$vbphrase[most_users_ever_online_was_x_y_at_z]</phrase></div>
<div>$activeusers</div>
</div>
</td>