:root {
  --audio-card-bg: var(--bs-body-bg);
  --audio-card-border: var(--bs-border-color);
  --audio-highlight: rgba(13, 110, 253, 0.15);
  --audio-primary: #0d6efd;
}

.modern-audio-card {
  background: var(--audio-card-bg);
  border: 1px solid var(--audio-card-border);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  margin-top: 2rem;
}

.card-header-bar {
  padding: 1.25rem;
  display: flex;
  align-items: center;
  cursor: pointer;
  user-select: none;
  background: var(--audio-card-bg);
}

.card-header-bar:hover {
  background: var(--bs-tertiary-bg);
}

.play-icon-wrapper {
  font-size: 1.5rem;
  color: var(--audio-primary);
  margin-right: 1rem;
  display: flex;
  align-items: center;
}

.card-title-text {
  font-weight: 600;
  font-size: 1.1rem;
  flex-grow: 1;
  color: var(--bs-heading-color);
}

.expand-chevron {
  transition: transform 0.3s ease;
  font-size: 1.2rem;
  color: var(--bs-secondary-color);
}

.modern-audio-card.expanded .expand-chevron {
  transform: rotate(180deg);
}

.card-expandable-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.5s ease-in-out;
  border-top: 0px solid transparent;
}

.modern-audio-card.expanded .card-expandable-content {
  max-height: 2000px;
  border-top: 1px solid var(--audio-card-border);
}

.inner-content {
  padding: 1.5rem;
}

.audio-description {
  color: var(--bs-secondary-color);
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 1.5rem;
}

.transcript-container {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--audio-card-border);
}

.transcript-title {
  font-weight: 700;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--bs-secondary-color);
  margin-bottom: 1rem;
  display: block;
}

.transcript-body {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--bs-body-color);
}

.transcript-sentence {
  transition: background-color 0.3s ease, color 0.3s ease;
  padding: 2px 4px;
  border-radius: 4px;
  cursor: pointer;
}

.transcript-sentence.active {
  background-color: var(--audio-highlight);
  color: var(--audio-primary);
  font-weight: 500;
}

.transcript-sentence:hover {
  background-color: var(--bs-tertiary-bg);
}