body{
    position: relative;
}
body:after{
    content: '';
    pointer-events: none;
    z-index: 99999;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;

    background: linear-gradient(
        to bottom,
        rgba(255,0,0, 0),
        rgba(255,0,0, 0) 50%,
        rgba(255,0,0, 0.05) 50%,
        rgba(255,0,0, 0.05)
    );
    background-size: 100% 3rem;
}