#primero {
    margin-left: auto;
    margin-right: auto;
    width: 130px;
    margin-top: 15px;
    display: flex;
    align-items: center;
}

#segundo
{
    margin-top:5%;
    text-align:center;
}

#boton_validar:hover {
	background-color: #8bacb8;	
}

#tercero {
    float: left;
    display: flex;
    align-items: center;
}