html {
     height: 100%;
 }
 body {
     font: 200% sans-serif;
     background-color: #dddddd;
     height: 100%;
     display: -webkit-box;
     display: -webkit-flex;
     display: -ms-flexbox;
     display: flex;
     -webkit-box-align: center;
     -webkit-align-items: center;
     -ms-flex-align: center;
     align-items: center;
     -webkit-box-pack: center;
     -webkit-justify-content: center;
     -ms-flex-pack: center;
     justify-content: center;
 }
 .zentriert {
     background-color: #dddddd;
     color: rgba(182, 236, 230, 0.93);
     padding: 1em;
     border: 1px solid #dddddd;
     border-radius: 4px;
 }