body {
    font-family: arial;
    margin: 0;
    padding: 0;
}
h2.introduccion {
    font-size: 49px;
    text-shadow: 0px 3px 4px rgba(0,0,0,.5);
}
#intro {
    background: url(img/parallax.jpg) 50% 0 fixed;
    min-height: 100px;
    margin: 0 auto;
    width: 100%;
    padding: 100px 0;
}
.intro-unit {
    color: #fff;
    padding: 100px;
    text-align: center;
}