body {
  position: relative !important;
}

.intro {
    background: url("../img/intro.jpg")no-repeat center center fixed;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}
.navbar {
  background-color: transparent;
  transition: background-color 0.7s ease;
}

.top-nav-collapse {
        background-color: #263238;
        transition: background-color 0.7s ease;
    }
    @media only screen and (max-width: 768px) {
        .navbar {
            background-color: #263238;
            transition: background-color 0.7s ease;
        }
    }