:root {
  --bg: #111;
  --bg-card: #1a1a1a;
  --border: #2a2a2a;
  --text: #e5e5e5;
  --text-muted: #999;
  --accent: #7c6cf0;
  --radius: 8px;
  --font: 'Noto Sans SC', system-ui, sans-serif;
  --max-width: 680px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

/* Header */
.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--bg);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1rem 1rem 0.75rem;
}

.header-inner h1 {
  font-size: 1.1rem;
  font-weight: 700;
}

.tagline {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.15rem;
}

.header-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 0.75rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Layout */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1rem 1rem 3rem;
}

.hidden { display: none !important; }

.section-label {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

/* Today card */
.today-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin-bottom: 1.5rem;
}

.today-artist {
  font-size: 0.85rem;
  color: var(--accent);
}

.today-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0.25rem 0 0.5rem;
  line-height: 1.3;
}

.today-date {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.today-tags {
  display: flex;
  gap: 0.5rem;
  margin: 0.75rem 0 1rem;
  font-size: 0.75rem;
  color: var(--text-muted);
}

.today-tags span {
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
}

.btn-primary {
  display: block;
  width: 100%;
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 500;
  font-family: inherit;
  cursor: pointer;
}

.btn-primary:active { opacity: 0.85; }

/* Filters */
.filters {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.filter-group label {
  display: block;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
}

.filter-group select,
.filter-group input {
  width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.6rem 0.75rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-family: inherit;
}

/* History list */
.history-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.history-item {
  display: block;
  width: 100%;
  text-align: left;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem 1rem;
  color: var(--text);
  font-family: inherit;
  cursor: pointer;
}

.history-item:active { background: #222; }

.history-date {
  display: block;
  font-size: 0.75rem;
  color: var(--text-muted);
}

.history-artist {
  display: block;
  font-size: 0.8rem;
  color: var(--accent);
  margin-top: 0.15rem;
}

.history-title {
  display: block;
  font-size: 1rem;
  font-weight: 600;
  margin-top: 0.1rem;
}

/* Lesson view */
.lesson-view {
  padding-top: 0.5rem;
}

.btn-back {
  background: none;
  border: none;
  color: var(--accent);
  font-size: 0.9rem;
  font-family: inherit;
  padding: 0.5rem 0;
  margin-bottom: 0.75rem;
  cursor: pointer;
}

.lesson-header h2 {
  font-size: 1.4rem;
  font-weight: 700;
  line-height: 1.3;
}

.lesson-header p {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
  margin-bottom: 1.25rem;
}

.lesson-body {
  padding-bottom: 2rem;
}

/* Markdown */
.markdown-body h1 { font-size: 1.3rem; margin: 1.5rem 0 0.75rem; color: var(--accent); }
.markdown-body h2 { font-size: 1.15rem; margin: 1.5rem 0 0.75rem; padding-bottom: 0.4rem; border-bottom: 1px solid var(--border); }
.markdown-body h3 { font-size: 1rem; margin: 1rem 0 0.5rem; }
.markdown-body p { margin-bottom: 0.85rem; }
.markdown-body ul, .markdown-body ol { padding-left: 1.25rem; margin-bottom: 0.85rem; }
.markdown-body li { margin-bottom: 0.35rem; }

.markdown-body table {
  display: block;
  width: 100%;
  overflow-x: auto;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.85rem;
  -webkit-overflow-scrolling: touch;
}

.markdown-body th, .markdown-body td {
  border: 1px solid var(--border);
  padding: 0.5rem;
  text-align: left;
  white-space: nowrap;
}

.markdown-body th { background: var(--bg-card); }

.markdown-body blockquote {
  background: var(--bg-card);
  border-left: 3px solid var(--accent);
  padding: 0.75rem 1rem;
  margin: 1rem 0;
  border-radius: 0 var(--radius) var(--radius) 0;
  font-size: 0.9rem;
}

.markdown-body blockquote.quiz p:last-child {
  display: none;
}

.markdown-body blockquote.quiz.revealed p:last-child {
  display: block;
  margin-top: 0.5rem;
  color: var(--accent);
}

.quiz-toggle {
  display: block;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.35rem 0.75rem;
  border-radius: 4px;
  font-size: 0.8rem;
  font-family: inherit;
  margin-bottom: 0.5rem;
  cursor: pointer;
}

.lyric-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  margin: 1rem 0;
  font-size: 0.95rem;
}

.lyric-card strong { color: var(--accent); }

.speak-btn {
  display: inline-block;
  margin-top: 0.75rem;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.35rem 0.75rem;
  border-radius: 4px;
  font-size: 0.8rem;
  font-family: inherit;
  cursor: pointer;
}

.speak-btn:active { opacity: 0.85; }

.speak-btn.playing {
  border-color: var(--accent);
  color: var(--accent);
}

/* Audio player */
.audio-section {
  background: linear-gradient(135deg, rgba(124, 108, 240, 0.12), rgba(124, 108, 240, 0.04));
  border: 1px solid rgba(124, 108, 240, 0.3);
  border-radius: var(--radius);
  padding: 1rem 1.1rem;
  margin: 1rem 0;
}

.audio-label {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.audio-hint {
  color: var(--text-muted);
  font-size: 0.82rem;
  margin-bottom: 0.85rem;
}

.audio-player-wrap {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.audio-player {
  width: 100%;
  height: 44px;
  border-radius: var(--radius);
}

.playback-speed {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  flex-wrap: wrap;
}

.speed-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-right: 0.15rem;
}

.speed-btn {
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
  font-size: 0.78rem;
  font-family: inherit;
  cursor: pointer;
  min-height: 32px;
}

.speed-btn.active {
  background: rgba(124, 108, 240, 0.18);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 600;
}

.today-card .audio-section {
  margin-top: 0.75rem;
  margin-bottom: 0.25rem;
}

.lesson-header .audio-section {
  margin-bottom: 1rem;
}

.markdown-body hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 1.5rem 0;
}

.loading, .empty-state, .error-state {
  color: var(--text-muted);
  padding: 1.5rem 0;
  text-align: center;
  font-size: 0.9rem;
}

.error-state { color: #e57373; }

.site-footer {
  text-align: center;
  padding: 1.5rem 1rem;
  color: var(--text-muted);
  font-size: 0.75rem;
  border-top: 1px solid var(--border);
}

@media (min-width: 480px) {
  .btn-primary { width: auto; min-width: 10rem; }
}