header{ position:absolute; z-index:3; left:0; top:0;}
header > a > span{ color:#fff; }
section > div.main1{ width:100%; height:420px; background-position:center center; background-size:auto 100%; background-repeat:no-repeat; background-repeat:no-repeat;}
section > div.main2{ width:100%; display:block; max-width:800px; margin:auto; margin-top:4em; margin-bottom:4em;}