discourse/app/assets/stylesheets/mobile/select-kit/category-drop.scss

.select-kit {
  &.combo-box {
    &.category-drop {
      .category-drop-header {
        font-size: $font-0;

        .d-icon {
          font-size: $font-0;
        }
      }

      .select-kit-row {
        font-weight: normal;
      }
    }
  }
}