1. Customizable Select element

    Customization of the `<select>` element's appearance. Previously envisioned as a separate element (`<selectlist>` or `<selectmenu>`).

  2. css property: appearance: base-select

  3. css property: appearance: base-select: base styling for list box: `<select multiple>` or `<select size="3">`

  4. css property: appearance: base-select: base styling for multiple dropdown: `<select multiple size="1">`

  5. css property: appearance: base-select: base styling for single dropdown: `<select>`