#site-navigation {
 display: none;
}

#masthead {
 padding-top: 0;
}

img.header-image {
 margin-top: 0;
}
<style>
hr { 
    display: block;
    margin-top: 0.5em;
    margin-bottom: 0.5em;
    margin-left: auto;
    margin-right: auto;
    border-style: inset;
    border-width: 3px;
} 
</style>