style.css

body {
    background: #141414;
}

#rate {
    -webkit-appearance: none;
    height:4px;
    background: white;
    outline: none;
}

#rate::-webkit-slider-thumb {
    -webkit-appearance: none; 
    appearance: none;
    width: 20px; 
    height: 20px; 
    background: #007BFF;
    cursor: pointer; 
}

#rate::-moz-range-thumb {
    width: 20px; 
    height: 20px; 
    background: #007BFF;
    cursor: pointer; 
}
#pitch {
    -webkit-appearance: none;
    height:4px;
    background: white;
    outline: none;
}

#pitch::-webkit-slider-thumb {
    -webkit-appearance: none; 
    appearance: none;
    width: 20px; 
    height: 20px; 
    background: #007BFF;
    cursor: pointer; 
}

#pitch::-moz-range-thumb {
    width: 20px; 
    height: 20px; 
    background: #007BFF;
    cursor: pointer; 
}