some css styling for a custom slider

slider.css

.audio-player-loudnesshead {
    width: var(--font-size-small);
    height: var(--font-size-small);
    background: var(--color-5);
    border-radius: 50%;
    z-index: 1;
    position: absolute;
    left: 50%;
    transform: translateY(-50%) translateX(-50%) translateY(var(--font-size-small));
    bottom: 20%;
}

.audio-player-scrubbar-buffered {
    background: var(--color-3);
}

.audio-player-scrubbar {
    background: var(--color-5);
    position: absolute;
    height: 3px;
    width: 100%;
    top: 50%;
    left: 0;
    transform: translateY(-50%);
}

.audio-player-loudnessbar {
    background: var(--color-5);
    position: absolute;
    width: 3px;
    height: 100%;
    left: 50%;
    bottom: 0;
    transform: translateX(-50%);
}

.audio-player-scrubbar-buffered {
    background: var(--color-8);
    position: absolute;
    height: 4px;
    top: 50%;
    left: 0;
    transform: translateY(-100%);
    transition: width 1s ease;
}

.play-adjust {
    margin-left: 2px;
}

.pause-adjust {
    margin: 0 1px;
}

.audio-player-controls {
    background: var(--color-4);
    border-radius: 27px;
    border: 1px solid;
}

.loudness-control:hover .loudness-bar {
    display: initial;
}

.loudness-bar {
    position: absolute;
    width: var(--font-size-medium);
    height: 100px;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
}

.audio-player-loudnessbackground {
    position: absolute;
    height: calc(100% + 54px);
    border-radius: 27px;
    left: 0;
    width: calc(100% - 2px);
    bottom: -35px;
}

.loudness-button {
    height: 27px;
    z-index: 1;
    position: relative;
}