body {margin: 0px;
font-family: Arial, Helvetica, sans-serif;
}

#kopf{
    width: 100%;
    padding-bottom: 36px;
    text-align: center;
    background-color: black;
    }
#kopf a {
    color: #ecf0f1;
    text-decoration: none;
    font-size: 200%;
    font-weight: bold;
    display: inline-block;
    margin-top: 50px ;
}
#nav a {
    width: 20%;
    float:left;
    text-align: center;
    text-decoration: none;
    color: black;
    padding-top: 8px;
    padding-bottom: 8px;
}

#nav a:hover {
    background-color: #ecf0f1;
    font-weight: bolder; 
}
#gruen {
    border-top: solid 5px green;
}
#rot {
    border-top: solid 5px red;
}
#orange{
    border-top: solid 5px orange;
}
#blau {
    border-top: solid 5px blue;
}
#pink {
    border-top: solid 5px pink;
}

#main {
    max-width: 800px;
    margin: auto;
    padding: 16px;
}

#footer {
    text-align: center;
    color: grey;
    padding: 16px;
}