.bm-lang{
    display: block;
    position: absolute;
    width: 50px;
    min-height: 30px;
    list-style: none;
    padding: 0;
    left: 50%;
    top: 50%;
    cursor: pointer;
}
.bm-lang li{
    position: relative;
    opacity: 0;
    visibility: hidden;
    transition: .25s linear;
    height: 0;
}
.bm-lang:hover li{
    opacity: 1;
    visibility: visible;
    height: 30px;
}
.bm-lang li > svg,
.bm-lang > svg{
    width: 30px;
    height: 30px;
}
.bm-lang li:nth-of-type(1){
    margin-top: 5px;
}
.bm-lang a{
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 2;
    cursor: pointer;
}
.bm-lang__arrow{
    width: 7px;
    height: 7px;
    overflow: hidden;
    position: absolute;
    display: block;
    top: 6px;
    margin: auto;
    right: -5px;
}
.bm-lang__arrow::before{
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 7px;
    height: 7px;
    transition: .25s linear;
    background-image:url(../lang/triangle.png);
    background-position: center center;
    background-size: contain;
    background-repeat: no-repeat;
    transform: rotate3d(1, 0, 0, -180deg);
}
.bm-lang:hover .bm-lang__arrow::before{
    transform-origin: 50% 50%;
    transform: rotate3d( 1, 0, 0, 0deg);
}