footer {
    position: fixed;
    left: 0;
    bottom: 0;
    width: 100%;
    color: black;
    text-align: center;
}

.mt-1{margin-top: 1em}
.mt-2{margin-top: 2em}
.mt-3{margin-top: 3em}
.mt-4{margin-top: 4em}
.mt-5{margin-top: 5em}

.mb-1{margin-bottom: 1em}
.mb-2{margin-bottom: 2em}
.mb-3{margin-bottom: 3em}
.mb-4{margin-bottom: 4em}
.mb-5{margin-bottom: 5em}

.list-group > .list-group-item.active > a,
.list-group > .list-group-item > a:hover,
.list-group > .list-group-item > a:focus {
    color: white;
    background: #337ab7;
}