html,body{
   margin:0;
   padding:0;
}
body{
    background:#f1f0e5;
}
header{
   background:url("http://alicex.jp/data/ilyet/img/ilyet_upld_1.png");
   margin:0;
   padding:0;
}
header div{
   margin:0 0 0 50vw;
   padding:10% 0 0;
   height:50vh;
   background:#fff;
   text-align:center;
}
h1{

}
nav{
   position:flex;
   top:0px;
   left:50%;
   index:1;
   text-align:center;
   background:#fff;
   border-top:1px solid #fff;
   border-bottom:1px solid #f1f0e5;
}
nav ul{
   list-style-type: none
}
nav ul li{
   display:inline-block;
   margin:.3em 1em;
}

#flexbox {
    display: -webkit-flex;
    display: flex;
    background:#f1f0e5;
    max-width:700px;
    margin:2em auto;
}
#flexbox div{
    margin: 10px;
    padding: 10px;
    flex: 1;
    justify-content:space-between;
    align-items:stretch;
    align-content:space-between;
    background:#fff;
}