.slider-container {
  width: 100%;
  max-width: 500px;
  margin: auto;
  text-align: center;
}
.slider-container .slider {
  width: 100%;
  -webkit-appearance: none;
  -moz-appearance: none;
       appearance: none;
  height: 15px;
  background: #ddd;
  outline: none;
  border-radius: 5px;
  -webkit-transition: background 0.3s ease;
  transition: background 0.3s ease;
}
.slider-container .slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 25px;
  height: 25px;
  background: #4CAF50;
  border-radius: 50%;
  cursor: pointer;
}
.slider-container .slider::-moz-range-thumb {
  width: 25px;
  height: 25px;
  background: #4CAF50;
  border-radius: 50%;
  cursor: pointer;
}
.slider-container #sliderValue {
  font-size: 1.2em;
  font-weight: bold;
}