metamask-extension/ui/pages/swaps/transaction-settings/index.scss

.transaction-settings {
  &__content {
    @include screen-sm-max {
      height: 100%;
    }
  }

  &__button-group {
    & &-custom-button {
      cursor: text;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
      min-width: 72px;
      margin-right: 0;
    }
  }

  &__custom-input {
    display: flex;
    justify-content: center;

    input {
      border: none;
      width: 64px;
      text-align: center;
      background: var(--color-primary-default);
      color: var(--color-primary-inverse);
      font-weight: inherit;
      outline: none;

      &::-webkit-input-placeholder { /* WebKit, Blink, Edge */
        color: var(--color-primary-inverse);
      }

      &:-moz-placeholder { /* Mozilla Firefox 4 to 18 */
        color: var(--color-primary-inverse);
        opacity: 1;
      }

      &::-moz-placeholder { /* Mozilla Firefox 19+ */
        color: var(--color-primary-inverse);
        opacity: 1;
      }

      &:-ms-input-placeholder { /* Internet Explorer 10-11 */
        color: var(--color-primary-inverse);
      }

      &::-ms-input-placeholder { /* Microsoft Edge */
        color: var(--color-primary-inverse);
      }

      &::placeholder { /* Most modern browsers support this now. */
        color: var(--color-primary-inverse);
      }
    }

    input::-webkit-outer-spin-button,
    input::-webkit-inner-spin-button {
      /* display: none; <- Crashes Chrome on hover */
      -webkit-appearance: none;
      margin: 0; /* <-- Apparently some margin are still there even though it's hidden */
    }

    input[type=number] {
      -moz-appearance: textfield;
    }

    &--danger {
      input {
        background: var(--color-error-default);
      }
    }
  }

  &__percentage-suffix {
    position: absolute;
    right: 5px;
  }
}