Range Slider

RangeSlider selects a start and an end on one track with two thumbs. Use it for filters where both bounds are meaningful: a price band, a QA score window, a time slice, a search radius range. Name the group and both thumbs. The group needs a visible label, aria-label or aria-labelledby; the thumbs need startLabel and endLabel. label, showValue, formatValue, locale and ticks work as they do on Slider. The header's readout shows both ends, start then end, joined with an en dash (20; 80); each thumb's aria-valuetext is its own formatted value, and each thumb has its own value bubble while you drag it or step it with the keyboard. The bubble rolls its digits with the default format and shows formatValue text as plain text. Motion matches Slider: spring for clicks and keys, none while dragging, a stretch past an end, a coast after a fast release and a bump at a limit, all off under reduced motion. A thumb held back by its neighbor does not stretch toward it. ui-core's showInput is not part of RangeSlider (contract RS-5; Chris approved with Slider SL-4). Compose two NumberFields beside the track and keep min, max, step and the tuple in sync; see the Slider usage doc for a single-value composition example. The slider fills the width of its container. Its track is 6px and its thumbs are 20px, which sets the height of the control; a header row sits above it with a label or showValue, and marks sit below it with ticks. Pointer presses register in a 24px band across the track (44px on coarse pointers); a press on the track moves the nearest thumb.