How to centralize image logo

Hello, please I need help centralizing my logo on https://www.thenetng.com

style.css

.header-content{padding:10px 15px;}

.logo {float: center;}
.logo h1#site-title{font:bold 32pt arial;}

header.php

</div><!– .logo /–>
<?php tie_banner(‘banner_top’ , ‘<div class=”ads-top”>’ , ‘</div>’ ); ?>
<div class=”clear”></div>
</div>

My programming skill is below average. I will appreciate your help. Thank you