:root {
  /* The source is a still image; these are the system's conventions.
     Rule: opacity and background tint only. Nothing bounces, nothing slides far. */
  --dur-instant: 80ms; /* @kind other */
  --dur-fast: 120ms; /* @kind other */
  --dur-base: 180ms; /* @kind other */
  --dur-slow: 260ms; /* @kind other */
  --dur-chart: 520ms; /* @kind other */   /* bars/areas growing in on mount */

  --ease-out: cubic-bezier(0.22, 0.61, 0.36, 1); /* @kind other */
  --ease-standard: cubic-bezier(0.4, 0, 0.2, 1); /* @kind other */
  --ease-in: cubic-bezier(0.4, 0, 1, 1); /* @kind other */

  --transition-control: background-color var(--dur-fast) var(--ease-out), color var(--dur-fast) var(--ease-out), border-color var(--dur-fast) var(--ease-out), box-shadow var(--dur-fast) var(--ease-out);
  --transition-surface: background-color var(--dur-base) var(--ease-out), box-shadow var(--dur-base) var(--ease-out);
}