.slider {
  min-height: 15px;
}

/* input range slider */
.slider input[type="range"] {
  --value: 0%;
  --lower: var(--primary);
  --upper: rgba(255, 255, 255, 0.5);
  --size: 5px;
  --active-size: 8px;
  --thumb-size: 7px;
  --thumb-active-size: 10px;
  --thumb-color: #fff;

  cursor: pointer;
  background: linear-gradient(
    to right,
    var(--lower) 0%,
    var(--lower) var(--value),
    var(--upper) var(--value),
    var(--upper) 100%
  );
  border-radius: var(--size);
  height: var(--size);
  width: 100%;
  outline: none;
  touch-action: manipulation;
  -webkit-appearance: none;
  -moz-appearance: none;
  transition: height ease-in-out 0.1s;
}
.slider input[type="range"]:hover,
.slider input[type="range"]:active {
  height: var(--active-size);
}

/* thumb */
/* strangely I have to separate them, otherwise non of them recognizes the rule */
.slider input[type="range"]::-moz-range-thumb {
  width: var(--thumb-size);
  height: var(--thumb-size);
  background-color: var(--thumb-color);
  border-radius: 100%;
  cursor: pointer;
  transition: width ease-in-out 0.1s, height ease-in-out 0.1s;
}
.slider input[type="range"]:hover::-moz-range-thumb,
.slider input[type="range"]:active::-moz-range-thumb {
  width: var(--thumb-active-size);
  height: var(--thumb-active-size);
}

.slider input[type="range"]::-webkit-slider-thumb {
  width: var(--thumb-size);
  height: var(--thumb-size);
  background-color: var(--thumb-color);
  border-radius: 100%;
  cursor: pointer;
  -webkit-appearance: none;
  transition: width ease-in-out 0.1s, height ease-in-out 0.1s;
}
.slider input[type="range"]:hover::-webkit-slider-thumb,
.slider input[type="range"]:active::-webkit-slider-thumb {
  width: var(--thumb-active-size);
  height: var(--thumb-active-size);
}

.slider input[type="range"]::-ms-thumb {
  width: var(--thumb-size);
  height: var(--thumb-size);
  background-color: var(--thumb-color);
  border-radius: 100%;
  cursor: pointer;
  transition: width ease-in-out 0.1s, height ease-in-out 0.1s;
}
.slider input[type="range"]:hover::-ms-thumb,
.slider input[type="range"]:active::-ms-thumb {
  width: var(--thumb-active-size);
  height: var(--thumb-active-size);
}

/* edge */
.slider input[type="range"]::-ms-track {
  background: transparent;
  border-color: transparent;
  border-width: var(--size) 0;
  color: transparent;
  width: 100%;
  height: var(--size);
  cursor: pointer;
  transition: width ease-in-out 0.1s, height ease-in-out 0.1s;
}

.slider input[type="range"]::-ms-fill-lower,
.slider input[type="range"]:focus::-ms-fill-lower {
  background: var(--lower);
  border-radius: var(--size);
}

.slider input[type="range"]::-ms-fill-upper,
.slider input[type="range"]:focus::-ms-fill-upper {
  background: var(--upper);
  border-radius: var(--size);
}