This helpful tutorial is also applicable to Bootstrap: Customizing Input Type Range in Various Browsers.
If you access bootstrap.css from the most recent version, you can search for "range" and leverage the available code as a guide:
.form-range {
width: 100%;
height: 1.5rem;
padding: 0;
background-color: transparent;
-webkit-appearance: none;
-moz-appearance: none;
appearance: none;
}
.form-range:focus {
outline: 0;
}
.form-range:focus::-webkit-slider-thumb {
box-shadow: 0 0 0 1px #fff, 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
}
.form-range:focus::-moz-range-thumb {
box-shadow: 0 0 0 1px #fff, 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
}
.form-range::-moz-focus-outer {
border: 0;
}
.form-range::-webkit-slider-thumb {
width: 1rem;
height: 1rem;
margin-top: -0.25rem;
background-color: #0d6efd;
border: 0;
border-radius: 1rem;
-webkit-transition: background-color 0.15s ease-in-out, border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
transition: background-color 0.15s ease-in-out, border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
-webkit-appearance: none;
appearance: none;
}
@media (prefers-reduced-motion: reduce) {
.form-range::-webkit-slider-thumb {
-webkit-transition: none;
transition: none;
}
}
.form-range::-webkit-slider-thumb:active {
background-color: #b6d4fe;
}
.form-range::-webkit-slider-runnable-track {
width: 100%;
height: 0.5rem;
color: transparent;
cursor: pointer;
background-color: #dee2e6;
border-color: transparent;
border-radius: 1rem;
}
.form-range::-moz-range-thumb {
width: 1rem;
height: 1rem;
background-color: #0d6efd;
border: 0;
border-radius: 1rem;
-moz-transition: background-color 0.15s ease-in-out, border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
transition: background-color 0.15s ease-in-out, border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
-moz-appearance: none;
appearance: none;
}
@media (prefers-reduced-motion: reduce) {
.form-range::-moz-range-thumb {
-moz-transition: none;
transition: none;
}
}
.form-range::-moz-range-thumb:active {
background-color: #b6d4fe;
}
.form-range::-moz-range-track {
width: 100%;
height: 0.5rem;
color: transparent;
cursor: pointer;
background-color: #dee2e6;
border-color: transparent;
border-radius: 1rem;
}
.form-range:disabled {
pointer-events: none;
}
.form-range:disabled::-webkit-slider-thumb {
background-color: #adb5bd;
}
.form-range:disabled::-moz-range-thumb {
background-color: #adb5bd;
}