#slider {
    -webkit-appearance: none;
    width: 100%;
    height: 10px;
    border-radius: 5px;
    background: #d3d3d3;
    outline: none;
    opacity: 0.7;
    -webkit-transition: .2s;
    transition: opacity .2s;
}

#slider:hover {
    opacity: 1;
}

    #slider::-webkit-slider-thumb {
        -webkit-appearance: none;
        appearance: none;
        width: 20px;
        height: 20px;
        border-radius: 50%;
        background: lightseagreen;
        cursor: pointer;
    }

    #slider::-moz-range-thumb {
        width: 20px;
        height: 20px;
        border-radius: 50%;
        background: lightseagreen;
        cursor: pointer;
    }
#sliderContainer {
    width: 100%;
    box-sizing: border-box;
}