CSS で数値型の入力フィールド用に、視覚的に魅力的なカスタムの増分ボタンと減分ボタンを作成するにはどうすればよいですか?

<div class="input-group inline-group">
  <div class="input-group-prepend">
    <button class="btn btn-outline-secondary btn-minus">
      <i class="fa fa-minus"></i>
    </button>
  </div>
  <input class="form-control quantity" min="0" name="quantity" value="1" type="number">
  <div class="input-group-append">
    <button class="btn btn-outline-secondary btn-plus">
      <i class="fa fa-plus"></i>
    </button>
  </div>
</div>

$('.btn-plus, .btn-minus').on('click', function(e) {
  const isNegative = $(e.target).closest('.btn-minus').is('.btn-minus');
  const input = $(e.target).closest('.input-group').find('input');
  if (input.is('input')) {
    input[0][isNegative ? 'stepDown' : 'stepUp']()
  }
})

.inline-group {
  max-width: 9rem;
  padding: .5rem;
}

.inline-group .form-control {
  text-align: right;
}

.form-control[type="number"]::-webkit-inner-spin-button,
.form-control[type="number"]::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}