div{ 
  height: 650px; 
  background:#ccc; 
  /*the magic happens here*/
  border-top:42px solid #fff;
}
ul{
  top: 0; 
  width: 100%; 
  height:20px; 
  position: fixed; 
  background: deeppink; 
  margin:0;
  padding:10px; 
}
li{
  float:left;
  list-style:none;
  padding-left:10px;
}
div:first-of-type{ 
  margin-top:0; 
}