.jumbotron-extend {
    position: relative;
    height: 100vh;
    min-height: 300px;
    background: url(../images/top.jpg) no-repeat center center;
    background-size: cover;
}
.jumbotron-container {
    position: relative;
    top: 30%;
    transform: translateY(-30%);
}
.site-name {
    margin-bottom: 30px;
}
.btn-black {
    border-radius: 10;
    background-color: #000;
    color: #fff;
    font-family: 'Avenir', serif;
}