.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;
    -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;
    position: relative;
    width: 40px;
    height: 40px;
    background-color: #555;
    -webkit-border-radius: 15%;
    -moz-border-radius: 15%;
    -ms-border-radius: 15%;
    -o-border-radius: 15%;
    border-radius: 15%;
    -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: 13px;
    top: 17px;
    width: 15px;
    height: 15px;
    border-right: 4px solid white;
    border-top: 4px 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;
}

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

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