styles.css

:root {
  color-scheme: light dark;
  font-family: ui-sans-serif, system-ui, sans-serif;
}

main {
  max-width: 60rem;
  margin: 0 auto;
  padding: 1.5rem;
}

/* An author `display` rule beats the UA stylesheet's [hidden] { display: none },
   which left #working visible on load. Keep this above any display rules. */
[hidden] {
  display: none !important;
}

textarea {
  width: 100%;
  font: inherit;
  padding: 0.5rem;
}

#status,
#error {
  margin: 0.75rem 0;
}

#highlight {
  line-height: 1.9;
  margin-top: 1rem;
}

.aid-highlight span {
  border-radius: 3px;
  padding: 1px 2px;
}

#report {
  white-space: pre-wrap;
  font-family: ui-monospace, monospace;
  font-size: 0.9rem;
}

#error {
  color: crimson;
}

button {
  margin-top: 0.75rem;
  padding: 0.5rem 1rem;
}

fieldset {
  border: 1px solid currentColor;
  margin: 0.5rem 0;
}

details {
  margin-top: 0.5rem;
}
.controls {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.working {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin: 0;
  font-size: 0.9rem;
  opacity: 0.85;
}

.working-time {
  font-variant-numeric: tabular-nums;
}

.spinner {
  width: 0.9rem;
  height: 0.9rem;
  border: 2px solid currentColor;
  border-top-color: transparent;
  border-radius: 50%;
  animation: aid-spin 0.7s linear infinite;
}

@media (prefers-reduced-motion: reduce) {
  .spinner {
    animation-duration: 2s;
  }
}

@keyframes aid-spin {
  to {
    transform: rotate(1turn);
  }
}

.precision {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  font-size: 0.85rem;
  opacity: 0.85;
}

.precision a.current {
  font-weight: 600;
  text-decoration: none;
}