body {
 padding: 0;  
 margin: 0;
 background: rgb(14, 186, 238);
 text-align: center ;
 font-family: Arial;
 color: rgb(0, 0, 0);
}

header {

}

.mitte {
    display: flex;
    justify-content:  center;
    align-items: center;
}

#teaser {
    width: 100%;
    height: 300px;
}

#teaser img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

@media screen and (min-width: 500px) {
    #teaser {
        height: 500px;
    }
}

nav ul {
  list-style: none;
}

 nav ul li a {
    font-weight: 700px;
   
}

section {
margin-left: auto;
margin-right: auto;
}

nav ul li a {
    padding: 24px;
}

section {
max-width: 1200px;
margin-left: auto;
margin-right: auto;
}