.header-span {
    background: #000;
    height: 8rem;
    padding: 0 2rem;
    display:flex;
    justify-content:space-between;
    align-items:center;
}

footer {
    background: #000;
    color: #fff
}

.btn-success:hover {
    color: #fff;
    background-color: #e0fd02;
    border-color: #e0fd02;
    box-shadow:0 2px 5px 0 rgba(0, 0, 0, 0.2)
}