Laws of UX
Law of Proximity
Objects near each other are perceived as a group (Gestalt). Use spacing to create visual relationships — related form fields close together, unrelated sections further apart. Replaces the need for borders.
In plain terms
Things placed close together look related. Use spacing to group what belongs together.
Why this matters
Spacing alone tells people what belongs together. Get it wrong and a form or page reads as a jumble — a real problem for users with cognitive or low-vision needs trying to scan it.