body {
  background-color: #f8f9fa;
}

.study-card {
  max-width: 720px;
  margin: 2.5rem auto;
}

/* Rating sliders start in a visibly "not answered" state: greyed track, no
   visible thumb, until the participant's first interaction (spec 4.5 step 3). */
.rating-slider {
  width: 100%;
}

.rating-slider.untouched {
  opacity: 0.35;
}

.rating-slider.untouched::-webkit-slider-thumb {
  visibility: hidden;
}

.rating-slider.untouched::-moz-range-thumb {
  visibility: hidden;
}

.rating-slider-labels {
  display: flex;
  justify-content: space-between;
  font-size: 0.875rem;
  color: #6c757d;
}

.trial-audio-status {
  font-weight: 600;
}

.exit-screen {
  max-width: 560px;
  margin: 4rem auto;
  text-align: center;
}