header{
 border-top: 35px solid #659B9A;
box-shadow: -2px 2px 2px silver;
 
  width:100%;
  height:auto;
  background:#ffffff;
  color: #000;
  padding-bottom: 10px;
}

header .wrapper {display: flex; justify-content: center;flex-direction: column }

.startseite header{z-index:100;}