.boxgroesse {
    width: 67%;
     margin-bottom:22mm;
    font-size: 30pt;
    color: white;
    background-color: rgba(215, 239, 250, 0.7);
}
#box1 {
    box-shadow: rgb(102, 102, 102) 5px 0px 32px 8px;
    margin:auto;
    top:center;
    left: center;
    font-size: medium;
    color: white;
    margin-bottom:2mm;
    padding-bottom: 15px;
}



#box3 {
     box-shadow: rgb(102, 102, 102) 5px 15px 32px 8px;
     margin:auto;
    font-size: medium;
     border: separate;
     margin-bottom:2mm;
     color: white;
    table-layout:fixed;

}

#box4 {
     box-shadow: rgb(102, 102, 102) 5px 15px 32px 8px;
    margin:auto;
    font-size: medium;
    color: white;
     margin-bottom:3mm;

    table-layout:fixed;
    border: separate;

}
 body {
    background-image:url(stein02.jpg);

}

.container {
background: #CCC;
box-shadow: rgb(102, 102, 102) 0px 0px 0px 1px;
margin: 0 auto;
padding-top: 30px;
width: 68%;
text-align: center;
font-size: x-large;

}

ul {
list-style: none;
margin: 0;
padding: 0;
}

li {
float: left;
text-align: center;
width: 25%;
}

nav {
border: 1px solid #979696;
box-sizing: border-box;
background: #aaa;
margin: 0 -20px;
padding: 20px;
position: relative;
}

nav::before,
nav::after {
border-bottom: 12px solid transparent;
bottom: -13px;
content: "";
display: block;
height: 0;
position: absolute;
width: 0;
}

nav::before {
border-right: 20px solid #666;
left: -1px;
}

nav::after {
border-left: 20px solid #666;
right: -1px;
}

.content {
box-sizing: border-box;
padding: 20px;
}