.wave3{
    position: relative;
    width: 100%;
    z-index: 5;
    display: block;
    background: #000;
}
footer{
    z-index: 5;
    background: #fff;
}

#main > img.wave4,
.timelinesvg,
.timeline,
.wave3,
footer {
    margin-top: -1px;
}