:root{
  /* Motion is mechanical: short, linear-ish, no bounce, no overshoot. */
  --dur-instant:80ms; /* @kind other */
  --dur-fast:120ms; /* @kind other */
  --dur-base:180ms; /* @kind other */
  --dur-slow:320ms; /* @kind other */
  --dur-reveal:520ms; /* @kind other */

  --ease-mech:cubic-bezier(.2,0,.2,1); /* @kind other */      /* default: quick out, hard settle */
  --ease-out:cubic-bezier(.16,1,.3,1); /* @kind other */
  --ease-linear:linear; /* @kind other */

  --transition-control:background-color var(--dur-fast) var(--ease-mech),color var(--dur-fast) var(--ease-mech),border-color var(--dur-fast) var(--ease-mech),box-shadow var(--dur-fast) var(--ease-mech),transform var(--dur-fast) var(--ease-mech); /* @kind other */
  --transition-surface:border-color var(--dur-base) var(--ease-mech),background-color var(--dur-base) var(--ease-mech),transform var(--dur-base) var(--ease-mech); /* @kind other */

  /* Press = 1px mechanical nudge toward the shadow, never a scale-down */
  --press-translate:translate(2px,2px); /* @kind other */
}