:root{
  /* Radii are small and nearly uniform. Vehicles and sign panels are
     square; this system is not a rounded-card system. */
  --r-0:0; /* @kind radius */
  --r-1:2px;
  --r-2:4px;
  --r-3:6px;
  --r-pill:999px;

  --r-panel:var(--r-2);
  --r-control:var(--r-2);
  --r-media:var(--r-2);
  --r-badge:var(--r-1);

  --bw-hair:1px; /* @kind spacing */
  --bw-rule:2px; /* @kind spacing */
  --bw-accent:3px; /* @kind spacing */

  /* The cyan section rule: 40px of volt above every section heading. */
  --rule-w:40px; /* @kind spacing */
  --rule-h:2px; /* @kind spacing */
}