Okay fag nuts first go to acp>themes>templates>expand templates>main theme>index templates>index

Find {$headerinclude} under that put this code

<style type="text/css">
.you suck penis:D {
    background: #CCCCFF;
    border-top: 2px solid #000033;
    border-bottom: 2px solid #000033;
    border-left: 2px solid #000033;
    border-right: 2px solid #000033;
    text-align: center;
    margin: 10px auto;
    padding: 5px 20px;
    font-weight: bold;
}
</style>

Now after you do that we need to call the css class we just created so under {$header} or wherever you prefer put this

<p class="you suck penis:D">Welcome to blackninja! Where dicks are our thing!</p>

Hope you enjoy i'm a boss I know