metamask-extension/ui/components/app/custom-spending-cap/index.scss

.custom-spending-cap {
  &__input-value-and-token-name {
    display: contents;
  }

  &__max-button {
    position: relative;
  }

  &__input {
    width: 100%;

    &--button {
      background: none;
      color: var(--color-primary-default);
    }

    &--max-button {
      color: var(--color-text-alternative);
      background: none;
      position: absolute;
      margin-top: 55px;
      margin-inline-start: -75px;
      z-index: 1;
    }
  }

  #custom-spending-cap-input-value {
    color: var(--color-error-default);
    padding-inline-end: 60px;
  }

  input[type='number']::-webkit-inner-spin-button,
  input[type='number']:hover::-webkit-inner-spin-button {
    -webkit-appearance: none;
    display: none;
  }
}