.apst-wrapper,
.apst-wrapper::before,
.apst-wrapper::after,
.apst-wrapper *,
.apst-wrapper *::before,
.apst-wrapper *::after {
    -webkit-box-sizing: border-box;
       -moz-box-sizing: border-box;
        -ms-box-sizing: border-box;
         -o-box-sizing: border-box;
            box-sizing: border-box;
}

.apst-wrapper {
    display: none;
    position: fixed;
    z-index: 99999;
    cursor: pointer;
    box-sizing: border-box;

    /* No blue highlight when clicking on element on mobile devices */
    -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
    -webkit-tap-highlight-color: transparent;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
       -moz-user-select: none;
        -ms-user-select: none;
            user-select: none;
}

    .apst-top {
        top: 20px;
    }

    .apst-bottom {
        bottom: 20px;
    }

    .apst-left {
        left: 20px;
    }

    .apst-center {
        left: 50%;
        margin-left: -40px;
    }

    .apst-right {
        right: 20px;
    }

    .apst-button {
        display: block;
        opacity:0.85;
        position: relative;
        width: 50px;
        height: 50px;
        background-color: #555;
        -webkit-border-radius: 50%;
           -moz-border-radius: 50%;
            -ms-border-radius: 50%;
             -o-border-radius: 50%;
                border-radius: 50%;
        -webkit-transition: all 0.2s;
           -moz-transition: all 0.2s;
            -ms-transition: all 0.2s;
             -o-transition: all 0.2s;
                transition: all 0.2s;
    }

    .apst-button::before {
        content: "";
    display: block;
    position: relative;
    left: 16px;
    top: 21px;
    width: 18px;
    height: 18px;
    border-right: 6px solid white;
    border-top: 6px solid white;
    -webkit-transform: rotate(-45deg);
    -moz-transform: rotate(-45deg);
    -ms-transform: rotate(-45deg);
    -o-transform: rotate(-45deg);
    transform: rotate(-45deg);
    -webkit-transition: all 0.2s;
    -moz-transition: all 0.2s;
    -ms-transition: all 0.2s;
    -o-transition: all 0.2s;
    transition: all 0.2s;
    }

    .lt-ie9 .apst-button {
        background: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEAAAABABAMAAABYR2ztAAAAG1BMVEUAAAD////////////////////////////////rTT7CAAAACHRSTlMAOfJhxAy4AkQzkWYAAACBSURBVEjH7cyxCYBAFIPhiIituIGdpaULCJYWDmHpDCpyYwvhIcLxYq3c3wXCh1Tq62UVdHXzArRbpYEQGg2EQEIAJBRAQgAkFLD3JHygy0n4AEDCBwASAjDCB4wQgBEe4BMLgZs4o8NM4CaG6FCMBIw4JsQEASMGxJXPsSKV+m8XlKczI6Hk6gkAAAAASUVORK5CYII=') no-repeat scroll 8px 7px transparent;
    }

    .apst-button:hover {
        background-color: #333;
    }

    .apst-button:hover::before {
        border-color: white;
    }

    @media only screen and (max-width: 640px) {
        .apst-center {
            margin-left: -35px;
        }

        .apst-button {
            width: 70px;
            height: 70px;
        }

        .apst-button::before {
            left: 25px;
            top: 27px;
            width: 20px;
            height: 20px;
        }
    }

    @media only screen and (max-width: 400px) {
        .apst-center {
            margin-left: -30px;
        }

        .apst-button {
            width: 60px;
            height: 60px;
        }

        .apst-button::before {
            left: 21px;
            top: 23px;
            width: 18px;
            height: 18px;
            border-width: 5px;
        }
    }