Number fields are confusing; use input[type=number]/input[type=range] instead of custom sliders

[cvan]

It took me a good minute or so to discover that by horizontally dragging in a numeric text field that the value changes. It's neat. But wasn't discoverable. Perhaps make that more obvious or require the field to be focussed first (that's what Dev Tools do, anyway). And possibly consider using the native browser ones: input[type=number], input[type=range].

[cvan]

With input[type=number]:

Which also gives you free up/down keyboard navigation - which is super powerful (and something familiar to those using similar tools).