.cd-top {
    display: inline-block;
    height: 40px;
    width: 40px;
    position: fixed;
    bottom: 2px;
    right: 50%;
    box-shadow: 0 0 10px rgba(0,132,255, 0.05);
    border-radius: 40px;
    /* image replacement properties */
    overflow: hidden;
    text-indent: 100%;
    white-space: nowrap;
    background: #6cbd45 url(../img/cd-top-arrow.svg) no-repeat center 50%;
    visibility: hidden;
    opacity: 0;
    -webkit-transition: opacity .3s 0s, visibility 0s .3s;
    -moz-transition: opacity .3s 0s, visibility 0s .3s;
    transition: opacity .3s 0s, visibility 0s .3s;
}

    .cd-top.cd-is-visible, .cd-top.cd-fade-out, .no-touch .cd-top:hover {
        -webkit-transition: opacity .3s 0s, visibility 0s 0s;
        -moz-transition: opacity .3s 0s, visibility 0s 0s;
        transition: opacity .3s 0s, visibility 0s 0s;
    }

    .cd-top.cd-is-visible {
        /* the button becomes visible */
        visibility: visible;
        opacity: 1;
    }

    .cd-top.cd-fade-out {
        /* if the user keeps scrolling down, the button is out of focus and becomes less visible */
        opacity: .5;
    }

    .cd-top:hover {
        background-color: #0084ff;
        opacity: 1;
    }