<nav class="backNav">
  <button onclick="heelo()"><svg stroke="currentColor" fill="currentColor" stroke-width="0" viewBox="0 0 512 512" height="20px" width="20px" xmlns="http://www.w3.org/2000/svg"><path d="M427 234.625H167.296l119.702-119.702L256 85 85 256l171 171 29.922-29.924-118.626-119.701H427v-42.75z"></path></svg></button>
	<div></div>
</nav>

<style>
  .backNav {
    width: 100%;
    position: fixed;
    top: 0;
    z-index: 999999999;
  	height: 48px;
    display: flex;
    align-content: center;
    justify-content: space-between;
    padding: 0px 12px;
    background-color: #ffffff;
  }
  
  .backNav button{
background: inherit ; border:none; box-shadow:none; border-radius:0; padding:0; overflow:visible; cursor:pointer}
</style>
<script>
function heelo() {
history.back();
}

  if(window.location.pathname === "/"){
  const backNav = document.querySelector(".backNav");
backNav.style.cssText = 
  "display: none";
  }

</script>