.section {
    margin: 0 auto;
    width: 100%;
    background-color: red;
    position: fixed;
    left: 0;
}
#simulation {
    top: 0;
    height: 85vh;
}
#timeline {
    bottom: 0;
    height: 10vh;
}
hr {
    border: 0;
    height: 1px;
    background-image: linear-gradient(to right, rgba(0, 0, 0, 1), rgba(0, 0, 0, 1));
}