:root {
  --radius-none: 0px;
  --radius-sm: 0.25rem;   /* 4px  — badges, checkboxes */
  --radius-md: 0.5rem;    /* 8px  — buttons, inputs (interactive default) */
  --radius-lg: 0.75rem;   /* 12px — cards (surface default) */
  --radius-xl: 1rem;      /* 16px — modals, marked sections */
  --radius-2xl: 1.5rem;   /* 24px — hero blocks */
  --radius-full: 9999px;  /* pills, avatars, round buttons */

  /* Overridable per project: interactive elements read this first. */
  --radius-default: var(--radius-md);
}