val-web4

- let minor = 1, major = 6*minor, max = 6*major;
- let s = min || 0;
- let e = (max === 0 || max) ? max : 100;
- let v = (val === 0 || val) ? val : .5*(s + e);

// put all in a wrapper:
.wrap(role='group' aria-label='slider with ruler' style=`--min: ${s}; --val: ${v}; --max: ${e}`)
	// slider:
	input#r(type='range' list='l' min=min value=val max=max)
	// value display: