body{background-color:#000000; text-align:center;}
.logoinicio{  position:absolute;  
     top: 50%;  
     left: 50%;  
     width:30em;  
 
     margin-top: -9em; /*set to a negative number 1/2 of your height*/  
     margin-left: -15em; /*set to a negative number 1/2 of your width*/  
}
.logoinicio img{border:0;}
.aenorq{position:absolute; bottom:10px; right:10px;}