.clearfix:after {
content: ".";
display: block;
height: 0;
clear: both;
visibility: hidden;
}
.clearfix {display: inline-block;}
.clearfix {display: block;}

.izquierda{float: left}
.derecha{float: right}
.txtIzq{text-align: left}
.txtDer{text-align: right}
.txtCen{text-align: center}
.absoluta {position: absolute}
.oculta {display: none}
.muestra {display: block}
.alinea{display: inline}

:active, :focus{ outline:none;}

.message {
        text-align:center;
    color:yellow;
    font-size:14px;
}

.logo_roland {
        display:block;
        height:50px;
        left: 15px;
        position:relative;
        top:10px;
        width:180px;
}
     
#introducir_num_serie {
        /*width:200px;*/
        text-align:center;
        margin:0 auto;
        padding:20px;
        border: 1px solid #7CDDFF;
}