* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}

body{
    margin: 0px;
    overflow: hidden;
}

.arrow {
    position: absolute;
    background: none;
    width: 3em;
}

#uArrow {
    top: 0px;
    width: 100%;
}

#dArrow{
    bottom: 0px;
    width: 100%;
}

#lArrow{
    left: 0px;
    height: 100%;
}

#rArrow{
    right: 0px;
    height: 100%;
}