@import url('https://fonts.googleapis.com/css?family=Poppins&display=swap');

* {
    margin: 0;
    padding: 0;
    font-family: 'Poppins', sans-serif;
}
body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: #151515;
}
div {
    position: relative;
    display: block;
}
#rangeValue {
    position: relative;
    display: block;
    font-size: 8em;
    color: rgba(0,0,0,.8);
    font-weight: 800;
    z-index: 2;
    text-align: center;
}
#rangeValue::after {
    content: '%';
}
#fillRangeValue {
    position: fixed;
    top: 0;
    left: 0;
    width: 0;
    height: 100%;
    background: #00adff;
    z-index: 1;
}
.range {
    position: relative;
    width: 400px;
    height: 15px;
    -webkit-appearance: none;
    background: rgba(0,0,0,.8);
    outline: none;
    border-radius: 15px;
    box-shadow: 0 0 0 2px #151515, inset 0 0 5px #000;
    z-index: 2;
    overflow: hidden;
}

.range::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 15px;
    height: 15px;
    border-radius: 50%;
    background: #00adff;
    border: 4px solid #222;
    z-index: 2;
    box-shadow: -407px 0 0 400px #00adff;
}