.wave {
    position: fixed;
    width: 200%;
    height: 12em;
    bottom: 0;
    left: 0;
    background: rgba(255, 255, 255, 0.25);
    border-radius: 1000% 1000% 0 0;
    opacity: 0.8;
    animation: wave 10s linear infinite;
    transform: translate3d(0, 0, 0);
    z-index: -1;
}

    .wave:nth-of-type(2) {
        bottom: -1.25em;
        animation-duration: 18s;
        animation-direction: reverse;
        opacity: 0.8;
    }

    .wave:nth-of-type(3) {
        bottom: -2.5em;
        animation-duration: 20s;
        animation-direction: reverse;
        opacity: 0.9;
    }

@keyframes wave {
    0%, 100% {
        transform: translateX(0);
    }

    50% {
        transform: translateX(-50%);
    }
}