Strong spring
Stiffness k = 130 with light damping 9.5 creates that over-shoot "boing" as each button settles back to its post.
Buttons lean toward the pointer the closer it gets, then spring back to rest the moment you leave. Organic, elastic, alive.
Each button measures its own centre. When the pointer is within 240px, it applies a force proportional to distance squared; an underdamped spring integrator returns it smooth and elastic.
Stiffness k = 130 with light damping 9.5 creates that over-shoot "boing" as each button settles back to its post.
The label and meta shift in the opposite direction to the button shell — a subtle stretch that makes the whole element feel like one mass.
Physics are frame-rate independent via dt-scaled integration.