[css-forms-1] The pseudo elements for the "slider" controls do not support multiple thumbs

[mfreed7]

See https://open-ui.org/components/enhanced-range-input.explainer/ for an exploration of the concept (and use case) for multiple thumbs. That's particularly relevant to <input type=range> but perhaps it applies to other "slider" controls? Seems like maybe not.

Having more than one thumb is quite common. Many shopping filters use ranges, e.g. price range, number of bedrooms, time of day ranges, etc. And having more than one thumb introduces the need for more pseudo elements, or functional forms of the proposed pseudos (e.g. ::thumb(2)?).

[nt1m]

This needs work on the HTML side first but yeah I agree it would be cool to address.