JSFiddle - React, Tailwind, and code Playground

HTML

<div class="scroll-indicator">
    scroll down
    <div class="scroll-arrow-container">
        <div class="scroll-arrow"></div>
    </div>
</div>

SCSS

.scroll-indicator {
    position: absolute;
    bottom: 10%;
    right: 5%;
    z-index: 10;
    color: black;
    text-align: center;
    line-height: 1;
    transition: opacity 0.5s ease-in-out;
}
.scrolled .scroll-indicator {
    opacity: 0;
}
.scroll-arrow-container {
    position: relative;
    overflow: hidden;
    height: 23px;
}
.scroll-arrow {
    width: 100%;
    height: 100%;
    animation: slideOutIn 4s ease-in-out infinite;
}

$bigPercent: 15;
$percentLeft: 100 - $bigPercent;
@keyframes slideOutIn {
    0%, #{$percentLeft / 2}%, #{$percentLeft}%, 100% {
        transform: translateY(0);
    }
    #{$percentLeft / 3}%, #{$percentLeft * 2 / 3}% {
        transform: translateY(15%);
    }
    #{100 - $bigPercent / 2}% {
        transform: translateY(100%);
    }
    #{100 - $bigPercent / 2 + 0.0001}% {
        transform: translateY(-100%);
    }
}
.scroll-arrow::before,
.scroll-arrow::after {
    content: '';
    position: absolute;
    left: 30%;
    top: 35%;
    width: 19%;
    height: 18%;
    background-color: black;
    transform: skewY(25deg);
}
.scroll-arrow::after {
    transform: translateX(92%) skewY(-25deg);
}

JavaScript

function animateThings(currTime) {
	if(window.pageYOffset  != 0) {
		document.body.classList.add("scrolled");
	} else {
		document.body.classList.remove("scrolled");
	}
}

window.requestAnimationFrame(animateThings);