JSFiddle - React, Tailwind, and code Playground

HTML

<div class="background">
    <a href="top" class="b-to-top">to&nbsp;top</a>
</div>

CSS

.background {
    background: black;
    height: 300px;
}


.b-to-top {
    -webkit-transition: all linear .25s;
       -moz-transition: all linear .25s;
        -ms-transition: all linear .25s;
         -o-transition: all linear .25s;
            transition: all linear .25s;
    display: block;
    position: absolute;
    left: 50%;
    top: 20px;
    width: 70px;
    height: 70px;
    margin-left: -35px;
    border: 1px solid #b5b5b5;
    -webkit-border-radius: 50%;
       -moz-border-radius: 50%;
            border-radius: 50%;
    z-index: 999;
    background: #fd0;
    text-align: center;
    line-height: 70px;
    font-size: 18px;
    color: #5c5c5c;
    text-decoration: none
    }
    .b-to-top:after {
        content: "";
        position: absolute;
        width: 0;
        height: 0;
        left: 50%;
        top: 15px;
        margin-left: -10px;
        border-bottom: 10px solid #5c5c5c;
        border-left: 10px solid transparent;
        border-right: 10px solid transparent;
        z-index: 1000
        }
    .b-to-top:hover {
        background: #ff0;
        color: #000
        }
        .b-to-top:hover:after {
            border-bottom-color: #000
            }