.jahresbox {
    height: auto;
    width: auto;
    background-color: #303030;
    border:1px solid #000000;
    box-shadow: 0 0px 10px #000000;
   background-image: url("./images/obenlinks.png"), url("./images/obenrechts.png"), url("./images/obenmitte.png");
    background-position: left, right, top;
    background-size: 10px 84px;
    background-repeat: repeat-y, repeat-y, repeat-x;	
}

.imgadv {
 margin-left: 28%;
}

#blo1 {
display: block; 
position: relative; 
width: 30%; 
height: auto;
border: none;
}

.imgbild {
position: absolute;
top: 50%;
left: 50%;
margin-left: -15%;
margin-top: 5%;
}

.centered-element {
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}

#blo2 {
display: block; 
position: relative; 
width: 40%; 
height: auto;
border: none;
}

#blo3 {
display: block; 
position: relative; 
width: 30%; 
height: auto;
border: none;
}

#winter {
	margin: auto;
}