html, body, #bloc_page
    {
	background-color: White;
    height:100%;
    margin:0;
    padding:0;
    text-align:center;
    }
 
#invisible
    {
    height:100%;
    display:inline-block;
    vertical-align:middle;
	horizontal-align:middle; 
    }
     
#logointro
    {
    display:inline-block;  
    vertical-align:middle;
	horizontal-align:middle; 
    }