:root {
  --fg: #222;
  --muted: #666;
  --bg: #ffffff;
  --card: #ffffff;
  --audio-card: #f3f5f9;
  --border: #e2e2e2;
  --accent: #1f77ff;     /* blue used for headings + body in instructions */
  --action: #2e9e4f;     /* green Next / Submit button */
  --action-hover: #258a45;
  --error: #d9534f;
  --success: #2e7d32;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  color: var(--fg);
  background: var(--bg);
  line-height: 1.5;
}

.container {
  max-width: 760px;
  margin: 1.5rem auto;
  padding: 1.5rem 1.75rem;
  background: var(--card);
}

h2#studyTitle {
  text-align: center;
  color: var(--accent);
  font-size: 1.7rem;
  margin: 0 0 1.25rem;
}

.instructions h3 {
  color: var(--fg);
  margin: 0 0 0.5rem;
  font-size: 1.05rem;
}

.instructions p,
.instructions ul,
.instructions li {
  color: var(--fg);
}

.instructions p { margin: 0.4rem 0; }
.instructions ul { margin: 0.5rem 0 0.75rem 1.25rem; padding: 0; }
.instructions hr {
  border: 0;
  border-top: 1px solid var(--border);
  margin: 1rem 0;
}

#progress {
  text-align: center;
  font-size: 0.95rem;
  color: var(--muted);
  margin: 0.75rem 0 1rem;
}

.audio-card {
  background: var(--audio-card);
  border-radius: 6px;
  padding: 1rem 1.25rem;
  margin-bottom: 1rem;
}

.audio-block { margin: 0.6rem 0; }
.audio-block:first-child { margin-top: 0; }
.audio-block:last-child { margin-bottom: 0; }

.audio-block .label {
  font-weight: 700;
  margin-bottom: 0.4rem;
  color: var(--fg);
}

audio {
  width: 100%;
}

.audio-error {
  color: var(--error);
  font-size: 0.85rem;
  margin-top: 0.25rem;
}

.rating-container {
  margin: 1.25rem 0 0.5rem;
}

.rating-container label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 700;
  color: var(--fg);
}

.rating-container select {
  width: 100%;
  padding: 0.55rem 0.6rem;
  border: 1px solid #bdbdbd;
  border-radius: 4px;
  background: #fff;
  font-size: 1rem;
}

.btn-container {
  display: flex;
  gap: 0.5rem;
  margin-top: 1.25rem;
}

.btn-container button {
  padding: 0.55rem 1.4rem;
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.95rem;
}

#nextBtn,
#submitBtn {
  background: var(--action);
  border-color: var(--action);
  color: #fff;
}

#nextBtn:hover,
#submitBtn:hover {
  background: var(--action-hover);
  border-color: var(--action-hover);
}

button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.loading,
.preview-message {
  padding: 2rem;
  text-align: center;
  color: var(--muted);
}

#status {
  margin-top: 1rem;
  font-size: 0.95rem;
  text-align: center;
}

#status.error { color: var(--error); }
#status.success { color: var(--success); }