/* ============================================================
   集中の持続 (SART) — page-local styles. Linked after lab.css on
   lab/sart/ only. Digit stimulus + mask (ring), sized to match the
   Stroop word's clamp scale so the stage feels consistent across
   tests.
   ============================================================ */
.sart-digit {
  min-height: 1.15em;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--mono, var(--font-mono));
  font-variant-numeric: tabular-nums;
  font-size: clamp(64px, 13vw, 108px);
  font-weight: 700;
  line-height: 1;
  color: var(--ink, var(--color-ink));
}
.sart-mask {
  width: 0.85em;
  height: 0.85em;
  box-sizing: border-box;
  border: 6px solid var(--ink-soft, var(--color-ink));
  border-radius: 999px;
}
@media (max-width: 420px) {
  .sart-mask { border-width: 5px; }
}