Power css to little modify twenty twelve theme

body .site,
footer[role="contentinfo"]
{
box-shadow:none;
margin:0px auto;
padding:0px;
width:100%;
max-width:1600px;
}

body
{
background:#000;
}

hgroup,
.nav-menu,
.wrapper,
#primary,
.site-info
{
margin:auto;
max-width:1024px;
padding:0px 10px;
}

.main-navigation ul.nav-menu, .main-navigation div.nav-menu > ul,
.site-content article
{
border:0px;
}

.main-navigation
{
border-top:1px solid #d7d7d7;
border-bottom:1px solid #d7d7d7;
}
#secondary
{
display:none;
}