.main-content {
  min-height: calc(100vh - 78px);
}

.catalog-view {
  max-width: 1160px;
  margin: 0 auto;
  padding: 10vh 40px 48px;
}

.catalog-intro {
  max-width: 720px;
  padding: 30px 34px;
  border-left: 2px solid rgba(67, 130, 107, 0.55);
  background: linear-gradient(90deg, rgba(244, 240, 228, 0.82), rgba(244, 240, 228, 0.15));
}

.catalog-intro h1 {
  margin: 17px 0 13px;
  color: var(--indigo-deep);
  font-size: clamp(32px, 4vw, 52px);
  font-weight: 500;
  letter-spacing: 0.16em;
  white-space: nowrap;
}

.catalog-intro p:last-child {
  margin: 0;
  color: var(--ink-soft);
  font-size: 16px;
  line-height: 2;
  letter-spacing: 0.08em;
}

.course-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 15px;
  margin-top: 8vh;
}

.course-card {
  position: relative;
  min-height: 256px;
  padding: 28px 23px;
  overflow: hidden;
  border: 1px solid rgba(65, 90, 145, 0.22);
  background: rgba(242, 237, 224, 0.8);
  box-shadow: var(--shadow);
  text-align: left;
  transition: 220ms ease;
}

.course-card::after {
  position: absolute;
  right: -40px;
  bottom: -46px;
  width: 145px;
  height: 145px;
  border: 1px solid rgba(65, 90, 145, 0.15);
  border-radius: 50%;
  content: "";
}

.course-card:hover,
.course-card:focus-visible {
  border-color: rgba(67, 130, 107, 0.72);
  background: rgba(246, 242, 231, 0.94);
  transform: translateY(-7px);
}

.course-order {
  color: var(--cinnabar);
  font-family: var(--sans);
  font-size: 12px;
  letter-spacing: 0.15em;
}

.course-period {
  position: absolute;
  top: 25px;
  right: 21px;
  display: grid;
  width: 35px;
  height: 35px;
  place-items: center;
  border: 1px solid rgba(67, 130, 107, 0.5);
  border-radius: 50%;
  color: var(--jade-deep);
  font-size: 17px;
}

.course-card strong,
.course-card small,
.course-card i {
  display: block;
}

.course-card strong {
  max-width: 135px;
  margin-top: 42px;
  color: var(--indigo-deep);
  font-size: 24px;
  font-weight: 500;
  line-height: 1.5;
  letter-spacing: 0.18em;
}

.course-card small {
  margin-top: 11px;
  color: var(--ink-soft);
  line-height: 1.6;
}

.course-card i {
  margin-top: 18px;
  color: var(--jade-deep);
  font-size: 12px;
  font-style: normal;
  letter-spacing: 0.18em;
}

.catalog-note {
  margin-top: 38px;
  color: var(--ink-soft);
  font-size: 13px;
  letter-spacing: 0.25em;
  text-align: center;
}

.player-view {
  display: grid;
  grid-template-columns: minmax(180px, 250px) minmax(340px, 1fr) minmax(210px, 280px);
  gap: 18px;
  height: calc(100vh - 78px - 78px);
  padding: 18px 28px;
}

.course-sidebar,
.sections-sidebar,
.lyrics-panel {
  border: 1px solid rgba(65, 90, 145, 0.18);
  background: var(--paper-soft);
  box-shadow: var(--shadow);
  backdrop-filter: blur(14px);
}

.course-sidebar {
  padding: 30px 24px;
}

.course-sidebar h1 {
  margin: 17px 0 10px;
  color: var(--indigo-deep);
  font-size: 30px;
  font-weight: 500;
  line-height: 1.55;
  letter-spacing: 0.2em;
}

.course-sidebar > p:not(.eyebrow) {
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.9;
}

.course-sidebar .subtle-button {
  margin-top: 16px;
}

.course-mini-list {
  display: grid;
  gap: 7px;
  margin-top: 32px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.mini-course-button {
  padding: 10px 4px;
  border: 0;
  border-left: 2px solid transparent;
  background: transparent;
  color: var(--ink-soft);
  font-size: 13px;
  letter-spacing: 0.12em;
  text-align: left;
}

.mini-course-button:hover,
.mini-course-button.is-active {
  padding-left: 10px;
  border-left-color: var(--jade);
  color: var(--jade-deep);
}

.lyrics-panel {
  position: relative;
  overflow: hidden;
  background: rgba(239, 234, 221, 0.75);
}

.lyrics-scroll {
  height: 100%;
  overflow-y: auto;
  scrollbar-color: rgba(65, 90, 145, 0.3) transparent;
  scrollbar-width: thin;
}

.lyrics-list {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 11px;
  min-height: 100%;
  padding: 44vh 22px;
}

.lyric-line {
  max-width: 850px;
  padding: 5px 14px;
  border: 0;
  background: transparent;
  color: rgba(52, 69, 76, 0.54);
  font-size: clamp(17px, 1.7vw, 22px);
  line-height: 1.65;
  letter-spacing: 0.12em;
  text-align: center;
  transition: color 260ms ease, font-size 260ms ease, transform 260ms ease;
}

.lyric-line:hover {
  color: var(--jade-deep);
}

.lyric-line.is-active {
  color: var(--indigo-deep);
  font-size: clamp(23px, 2.25vw, 31px);
  font-weight: 600;
  transform: scale(1.03);
}

.lyric-section {
  margin: 18px 0 8px;
  color: var(--jade-deep);
  font-size: 15px;
  letter-spacing: 0.42em;
}

.lyric-section::before,
.lyric-section::after {
  color: var(--cinnabar);
  content: " · ";
}

.lyric-section.is-active {
  color: var(--jade-deep);
  font-size: 19px;
}

.lyrics-fade {
  position: absolute;
  right: 0;
  left: 0;
  z-index: 2;
  height: 16%;
  pointer-events: none;
}

.lyrics-fade-top {
  top: 0;
  background: linear-gradient(var(--paper-deep), transparent);
}

.lyrics-fade-bottom {
  bottom: 0;
  background: linear-gradient(transparent, var(--paper-deep));
}

.follow-button {
  position: absolute;
  right: 18px;
  bottom: 18px;
  z-index: 5;
  padding: 9px 14px;
  border: 1px solid rgba(67, 130, 107, 0.45);
  background: rgba(242, 237, 224, 0.92);
  color: var(--jade-deep);
  font-size: 12px;
  letter-spacing: 0.12em;
}

.sections-sidebar {
  padding: 22px 16px;
  overflow: hidden;
}

.sections-heading {
  display: flex;
  justify-content: space-between;
  padding: 4px 8px 14px;
  border-bottom: 1px solid var(--line);
}

.sections-heading h2 {
  margin: 9px 0 0;
  color: var(--indigo-deep);
  font-size: 21px;
  font-weight: 500;
  letter-spacing: 0.18em;
}

.sections-close {
  display: none;
  border: 0;
  background: transparent;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 30px;
}

.sections-list {
  height: calc(100% - 70px);
  padding: 11px 0;
  overflow-y: auto;
  scrollbar-color: rgba(65, 90, 145, 0.28) transparent;
  scrollbar-width: thin;
}

.section-link {
  display: flex;
  width: 100%;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 8px 9px;
  border: 0;
  border-left: 2px solid transparent;
  background: transparent;
  color: var(--ink-soft);
  font-size: 14px;
  text-align: left;
}

.section-link small {
  color: rgba(105, 122, 122, 0.74);
  font-family: var(--sans);
  font-size: 11px;
}

.section-link:hover,
.section-link.is-active {
  border-left-color: var(--jade);
  background: rgba(67, 130, 107, 0.08);
  color: var(--jade-deep);
}

.player-controls {
  position: fixed;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 10;
  display: grid;
  grid-template-columns: 52px minmax(145px, 260px) 52px minmax(140px, 1fr) 52px 34px 78px;
  gap: 13px;
  align-items: center;
  height: 78px;
  padding: 0 32px;
  border-top: 1px solid var(--line);
  background: rgba(238, 232, 217, 0.93);
  box-shadow: 0 -10px 30px rgba(46, 71, 122, 0.08);
  backdrop-filter: blur(18px);
}

.play-button {
  display: grid;
  width: 46px;
  height: 46px;
  place-items: center;
  border: 1px solid rgba(67, 130, 107, 0.6);
  border-radius: 50%;
  background: rgba(67, 130, 107, 0.1);
}

.play-icon {
  width: 0;
  height: 0;
  margin-left: 4px;
  border-top: 7px solid transparent;
  border-bottom: 7px solid transparent;
  border-left: 11px solid var(--jade-deep);
}

.is-playing .play-icon {
  width: 10px;
  height: 14px;
  margin: 0;
  border: 0;
  border-right: 3px solid var(--jade-deep);
  border-left: 3px solid var(--jade-deep);
}

.track-meta strong,
.track-meta span {
  display: block;
}

.track-meta strong {
  overflow: hidden;
  color: var(--indigo-deep);
  font-size: 14px;
  letter-spacing: 0.13em;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.track-meta span {
  margin-top: 5px;
  color: var(--jade-deep);
  font-size: 11px;
  letter-spacing: 0.12em;
}

.time-label {
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 12px;
}

input[type="range"] {
  height: 3px;
  accent-color: var(--jade);
  cursor: pointer;
}

.volume-button {
  display: grid;
  width: 30px;
  height: 30px;
  place-items: center;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--jade-deep);
  font-size: 12px;
}

.volume-button.is-muted {
  color: var(--ink-soft);
  text-decoration: line-through;
}