#vb {
    display: flex;
    align-items: center;
    justify-content: center;
}

video {
    max-width: 100%;
    height: auto;
}

section {
    background-color: #000;
}

footer {
    position: absolute;
    bottom: 0;
}

@media screen and (max-width: 500px) {
    video {
        width: 100%;
    }
}