Every block used to draw from one fixed scale: the same air above every heading, the same column width, the same button, everything centred. A theme changed the colours, the typeface and the corners, but never the proportions, so eighty pages on eighty themes still stood on one skeleton. Different clothes, one body.

A design control is one of those proportions, made variable. Ten dials, each with three to five honest positions and none of them a pixel: density is the vertical rhythm, measure the column width, type the size of the headings, buttons and buttonShape the call to action, align whether copy sits left or centred, headingCase and headingWeight the voice of the headings, gutter the side margins, gap how tightly cards pack. Every position is still a fluid clamp() over the page width, so a phone and a desktop each get their own end of the range.

They reach the blocks as CSS variables on the page root. The shared scale reads each value as var(--pk-…, fallback), so a block written against fluid.title gets the dial for free and a root that sets nothing renders exactly as before. A page wears a preset, recommended from its theme's moods and its seed or picked by the owner under Layout in the editor. A section may override any dial for itself alone, through its style: a hero that wants vast air on a compact page, a strip that must sit flush under the hero, one band forced onto the brand colour.