.v_slider {
    -webkit-appearance: slider-vertical;
    height: 100px;
    width: 50px;
    background: #d3d3d3;
    outline: none;
    opacity: 0.7;
    -webkit-transition: .2s;
    transition: opacity .2s;
}

.v_slider:hover {
    opacity: 1;
}

.v_slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 25px;
    height: 25px;
    background: #4CAF50;
    cursor: pointer;
}

.v_slider::-moz-range-thumb {
    width: 25px;
    height: 25px;
    background: #4CAF50;
    cursor: pointer;
}