body { --accent: var(--purple); }

#nback-stimulus {
  width: 150px;
  height: 150px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border-bright);
  border-radius: 12px;
  color: var(--purple);
  font-size: 78px;
  letter-spacing: 0;
}

.single-response { grid-template-columns: 1fr; }
.single-response .response-key { width: 100%; }

.nback-example {
  display: flex;
  justify-content: center;
  gap: 8px;
  width: 100%;
  margin: 1rem 0;
}

.nback-example span {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border-bright);
  border-radius: 5px;
  color: var(--text);
}

.nback-example .match { border-color: var(--purple); color: var(--purple); }