/* https://codepen.io/ewayma/pen/AJFzG */
.nav-tab {
    height: 50px;
    margin: 10px;
    position: absolute;
    right: 0px;
    bottom: 0px
}

.box {
    padding: 10px 20px;
    position: absolute;
    color: white;
    font-weight: bold;
    text-decoration: none;
    height: 40px;
    background: #5BADDE;
    width: 80px;
    cursor: pointer;
}

    .box:after {
        content: "";
        display: block;
        border-width: 20px 20px 0;
        border-style: solid;
        border-color: #5BADDE transparent transparent;
        margin-left: -20px;
        position: absolute;
        bottom: -20px;
        left: 50%
    }

    .box.prev-tab {
        right: 100px;    
    } 

    .box.prev-tab:after {
        border-width: 20px;
        border-left-color: transparent;
        border-left-width: 0;
        border-top-color: transparent;
        border-right-color: #5BADDE;
        margin: -20px 0 0;
        left: -20px;
        right: auto;
        top: 50%;
        bottom: auto
    }

    .box.next-tab {
        right: 10px;
    }

    .box.next-tab:after {
        border-width: 20px;
        border-right-width: 0;
        border-top-color: transparent;
        border-left-color: #5BADDE;
        margin: -20px 0 0;
        left: auto;
        right: -20px;
        top: 50%;
        bottom: auto
    }