.bg-azul {
    background-color: #000;
    color: #fff;
}
.logo
{
    width: 539px;
    height: 500px;
    background: url(../Imagenes/login_welcome.jpg);
    background-position:center center;
    background-repeat:no-repeat;
}

.signin-box {
    padding: 20px;
    background-color: #000;
    border: 1px solid #212529;
    border-radius: 5px;
}
.signin-box h3 {
    text-align:center;
}
.btn{
    border:solid 1px #fff;    
    min-width:39.3%;
}
.form-control{
    width:80%;
    margin:auto;
}