.redes { 
}
.redes a{ 
    background-image : url(../img/sprite.png); 
    background-color : transparent; 
    background-repeat: no-repeat; 
    height: 48px; 
    width : 48px;
    float : left;
    display : block;
    margin : 0 5px 0 0;
} 

#twitter_png { 
    background-position  : 0px 0px; 
} 

#twitter_png:hover { 
    background-position  : 0px -48px; 
} 

#facebook_png { 
    background-position  : -48px 0px; 
} 

#facebook_png:hover { 
    background-position  : -48px -48px; 
} 

#google_png { 
    background-position  : -96px 0px; 
} 

#google_png:hover { 
    background-position  : -96px -48px; 
} 

#youtube_png { 
    background-position  : -144px -0px; 
} 

#youtube_png:hover { 
    background-position  : -144px -48px; 
} 


#bloc_png { 
    background-position  : -192px -0px; 
} 

#bloc_png:hover { 
    background-position  : -192px -48px; 
} 


#linkedin_png:hover { 
    background-position  : -192px 0px; 
}