/* LIVEARTIST Academy — Modern Minimal Redesign */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --fg: #18181b;
  --fg-muted: #71717a;
  --bg: #fafafa;
  --bg-subtle: #f4f4f5;
  --card: #ffffff;
  --border: #e4e4e7;
  --accent: #6366f1;
  --accent-light: #a5b4fc;
  --primary: #18181b;
  --radius: 0.75rem;
  --max-w: 960px;
  --max-w-narrow: 720px;
  --transition: 0.2s ease;
}

body {
  font-family: "Inter", "Noto Sans JP", ui-sans-serif, system-ui, -apple-system,
    BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--fg);
  background: var(--bg);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--fg);
  text-decoration: none;
  transition: color var(--transition);
}
a:hover {
  color: var(--accent);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* ===== Header ===== */
.site-header {
  background: rgba(250, 250, 250, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition);
}
.site-header:hover {
  border-bottom-color: var(--border);
}
.header-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.875rem 1.5rem;
}
.site-logo {
  display: flex;
  align-items: center;
}
.site-logo:hover {
  text-decoration: none;
  opacity: 0.7;
}
.site-logo img {
  height: 24px;
  width: auto;
}
.header-nav {
  display: flex;
  gap: 2rem;
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.01em;
}
.header-nav a {
  color: var(--fg-muted);
  position: relative;
}
.header-nav a::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--fg);
  transition: width var(--transition);
}
.header-nav a:hover {
  color: var(--fg);
  text-decoration: none;
}
.header-nav a:hover::after {
  width: 100%;
}

.category-bar {
  border-top: 1px solid var(--border);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.category-bar-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0.5rem 1.5rem;
  display: flex;
  gap: 0.25rem;
  white-space: nowrap;
}
.category-link {
  font-size: 0.75rem;
  padding: 0.25rem 0.625rem;
  border-radius: 9999px;
  background: transparent;
  color: var(--fg-muted);
  font-weight: 500;
  transition: all var(--transition);
}
.category-link:hover {
  background: var(--fg);
  color: #fff;
  text-decoration: none;
}

/* ===== Footer ===== */
.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 5rem;
}
.footer-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 2.5rem 1.5rem;
  text-align: center;
}
.footer-links {
  display: flex;
  justify-content: center;
  gap: 2rem;
  font-size: 0.8125rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}
.footer-links a {
  color: var(--fg-muted);
  font-weight: 400;
}
.footer-links a:hover {
  color: var(--fg);
}
.footer-social {
  display: flex;
  justify-content: center;
  gap: 1.25rem;
  margin-bottom: 1.5rem;
}
.footer-social a {
  color: var(--fg-muted);
  transition: color var(--transition);
}
.footer-social a:hover {
  color: var(--fg);
}
.footer-copy {
  font-size: 0.75rem;
  color: var(--fg-muted);
  letter-spacing: 0.01em;
}

/* ===== Article Page ===== */
.post-main {
  max-width: var(--max-w-narrow);
  margin: 0 auto;
  padding: 3rem 1.5rem;
}
.post-article {
  background: transparent;
  padding: 0;
}
.post-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.25rem;
  font-size: 0.8125rem;
  color: var(--fg-muted);
}
.post-category-tag {
  color: var(--accent);
  font-size: 0.8125rem;
  font-weight: 500;
}
.post-category-tag:hover {
  color: var(--accent);
  text-decoration: underline;
}
.post-title {
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.35;
  margin-bottom: 2rem;
  letter-spacing: -0.025em;
}
.post-hero {
  width: 100%;
  border-radius: var(--radius);
  margin-bottom: 2.5rem;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}
.post-content {
  font-size: 1rem;
  line-height: 2;
}
.post-content h2 {
  font-size: 1.375rem;
  font-weight: 700;
  margin-top: 3rem;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}
.post-content h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
}
.post-content p {
  margin-bottom: 1.5rem;
}
.post-content ul,
.post-content ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}
.post-content li {
  margin-bottom: 0.5rem;
}
.post-content blockquote {
  border-left: 2px solid var(--border);
  margin: 2rem 0;
  padding: 0 1.5rem;
  color: var(--fg-muted);
}
.post-content img {
  border-radius: var(--radius);
  margin: 2rem auto;
}
.post-content h4 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-top: 2rem;
  margin-bottom: 0.625rem;
}
.post-content h5 {
  font-size: 1rem;
  font-weight: 600;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}
.post-content a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}
.post-content iframe {
  max-width: 100%;
  margin: 2rem auto;
  display: block;
  border-radius: var(--radius);
}
.post-content pre {
  background: #18181b;
  color: #e4e4e7;
  padding: 1.25rem 1.5rem;
  border-radius: var(--radius);
  overflow-x: auto;
  font-size: 0.875rem;
  line-height: 1.6;
  margin-bottom: 1.5rem;
}
.post-content code {
  background: var(--bg-subtle);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.875em;
}
.post-content pre code {
  background: none;
  padding: 0;
}
.post-content figure {
  margin: 2rem 0;
  text-align: center;
}
.post-content figcaption {
  font-size: 0.8125rem;
  color: var(--fg-muted);
  margin-top: 0.5rem;
}
.post-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  font-size: 0.9375rem;
}
.post-content th,
.post-content td {
  text-align: left;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
}
.post-content th {
  font-weight: 600;
  color: var(--fg-muted);
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.post-content strong {
  font-weight: 700;
}
.post-content em {
  font-style: italic;
}

/* ===== Author Info ===== */
.post-author {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}
.post-author-photo {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}
.post-author-name {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--fg);
}
.post-author-name a {
  color: var(--fg);
}
.post-author-name a:hover {
  color: var(--accent);
}

/* ===== YouTube Embed ===== */
.youtube-player {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  margin: 2rem 0;
  border-radius: var(--radius);
  overflow: hidden;
  background: #000;
}
.youtube-player iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  margin: 0;
  border: 0;
}

/* ===== Embedly Card ===== */
.embedly-card,
.embedly-card-hug {
  margin: 2rem 0;
}
.embedly-card a {
  text-decoration: none;
}

/* ===== Highlight Box ===== */
.highlight-box {
  background: var(--bg-subtle);
  border-left: 2px solid var(--fg);
  border-radius: 0;
  padding: 1.25rem 1.5rem;
  margin: 2rem 0;
  font-size: 0.9375rem;
  line-height: 1.8;
}
.highlight-box p {
  margin-bottom: 0.5rem;
}
.highlight-box p:last-child {
  margin-bottom: 0;
}

/* ===== Warning / Success Boxes ===== */
.warning {
  background: #fffbeb;
  border-left: 2px solid #f59e0b;
  border-radius: 0;
  padding: 1.25rem 1.5rem;
  margin: 2rem 0;
  font-size: 0.9375rem;
  line-height: 1.8;
}
.success {
  background: #f0fdf4;
  border-left: 2px solid #10b981;
  border-radius: 0;
  padding: 1.25rem 1.5rem;
  margin: 2rem 0;
  font-size: 0.9375rem;
  line-height: 1.8;
}

/* ===== Accordion ===== */
.accordion {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 2rem 0;
  overflow: hidden;
}
.accordion-toggle {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 1.25rem;
  background: transparent;
  border: none;
  cursor: pointer;
  text-align: left;
  font-family: inherit;
  font-size: 0.9375rem;
  color: var(--fg);
  transition: background var(--transition);
}
.accordion-toggle:hover {
  background: var(--bg-subtle);
}
.accordion-title {
  font-weight: 600;
  flex: 1;
  min-width: 0;
}
.accordion-badge {
  font-size: 0.6875rem;
  background: var(--fg);
  color: #fff;
  padding: 0.15rem 0.5rem;
  border-radius: 9999px;
  flex-shrink: 0;
  font-weight: 500;
}
.accordion-icon {
  flex-shrink: 0;
  width: 1.25rem;
  height: 1.25rem;
  transition: transform 0.2s;
}
.accordion-icon svg,
.accordion-toggle > svg {
  width: 1.25rem;
  height: 1.25rem;
  max-width: 1.25rem;
  max-height: 1.25rem;
  flex-shrink: 0;
  color: var(--fg-muted);
}
.accordion-toggle svg:not(.accordion-icon svg) {
  width: 1.25rem;
  height: 1.25rem;
  max-width: 1.25rem;
  max-height: 1.25rem;
  flex-shrink: 0;
}
.accordion.open .accordion-icon {
  transform: rotate(180deg);
}
.accordion-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}
.accordion.open .accordion-content {
  max-height: 2000px;
}
.accordion-content-inner {
  padding: 1rem 1.25rem;
  border-top: 1px solid var(--border);
  font-size: 0.9375rem;
  line-height: 1.8;
}
.accordion-content-inner p {
  margin-bottom: 0.75rem;
}
.accordion-content-inner p:last-child {
  margin-bottom: 0;
}

/* ===== Source Citation ===== */
.source-citation {
  font-size: 0.8125rem;
  color: var(--fg-muted);
  border-top: 1px solid var(--border);
  margin-top: 2rem;
  padding-top: 1rem;
  font-style: italic;
}

/* ===== Thumbnail List ===== */
.thumbnaillist {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin: 2rem 0;
}
.thumbnaillist img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: var(--radius);
}
.thumbnaillist a {
  display: block;
  border-radius: var(--radius);
  overflow: hidden;
  transition: opacity var(--transition);
}
.thumbnaillist a:hover {
  opacity: 0.8;
}

/* ===== Related Article (in-content) ===== */
.related-article,
.related-content {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.25rem;
  margin: 2rem 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: transparent;
  transition: background var(--transition);
}
.related-article:hover,
.related-content:hover {
  background: var(--bg-subtle);
  text-decoration: none;
}
.related-label {
  font-size: 0.6875rem;
  color: var(--accent);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.related-title {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--fg);
  line-height: 1.4;
}

/* ===== WordPress Legacy ===== */
.wp-caption {
  max-width: 100%;
  margin: 2rem auto;
  text-align: center;
}
.wp-caption img {
  border-radius: var(--radius);
}
.wp-caption-text {
  font-size: 0.8125rem;
  color: var(--fg-muted);
  margin-top: 0.5rem;
}
.wp-embedded-content {
  max-width: 100%;
  margin: 2rem 0;
}

/* ===== Share Link ===== */
.share_link {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.5rem 1rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  font-size: 0.8125rem;
  color: var(--fg-muted);
  transition: all var(--transition);
}
.share_link:hover {
  border-color: var(--fg);
  color: var(--fg);
  text-decoration: none;
}

/* ===== Related Posts ===== */
.related-posts {
  margin-top: 4rem;
}
.related-posts h2 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 1.25rem;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  color: var(--fg-muted);
}
.related-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
}
.related-card {
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
  padding: 0;
  border-radius: var(--radius);
  background: transparent;
  transition: opacity var(--transition);
  border: none;
}
.related-card:hover {
  opacity: 0.75;
  text-decoration: none;
}
.related-card img {
  border-radius: var(--radius);
  aspect-ratio: 16 / 9;
  object-fit: cover;
  width: 100%;
}
.related-card span {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--fg);
  line-height: 1.5;
}

/* ===== Category Page ===== */
.category-main {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 3rem 1.5rem;
}
.category-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
  letter-spacing: -0.025em;
}
.category-count {
  font-size: 0.875rem;
  color: var(--fg-muted);
  margin-bottom: 2.5rem;
}

/* ===== Pagination ===== */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}
.pagination-btn {
  display: inline-flex;
  align-items: center;
  padding: 0.5rem 1.25rem;
  border-radius: 9999px;
  font-size: 0.875rem;
  font-weight: 500;
  border: 1px solid var(--border);
  color: var(--fg);
  background: var(--card);
  transition: background var(--transition), border-color var(--transition);
  text-decoration: none;
}
.pagination-btn:hover {
  background: var(--bg-subtle);
  border-color: var(--fg-muted);
  text-decoration: none;
}
.pagination-disabled {
  opacity: 0.3;
  pointer-events: none;
}
.pagination-info {
  font-size: 0.8125rem;
  color: var(--fg-muted);
  font-variant-numeric: tabular-nums;
}

/* ===== 404 Error Page ===== */
.error-main {
  max-width: var(--max-w-narrow);
  margin: 0 auto;
  padding: 6rem 1.5rem;
  text-align: center;
}
.error-main h1 {
  font-size: 5rem;
  font-weight: 700;
  letter-spacing: -0.04em;
  color: var(--fg);
  margin-bottom: 0.5rem;
  line-height: 1;
}
.error-main p {
  font-size: 1rem;
  color: var(--fg-muted);
  margin-bottom: 2rem;
}
.error-home-link {
  display: inline-flex;
  align-items: center;
  padding: 0.625rem 1.75rem;
  border-radius: 9999px;
  font-size: 0.875rem;
  font-weight: 600;
  background: var(--fg);
  color: #fff;
  transition: opacity var(--transition);
}
.error-home-link:hover {
  opacity: 0.85;
  text-decoration: none;
  color: #fff;
}

/* ===== Article Grid ===== */
.article-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}
.article-card {
  display: flex;
  flex-direction: column;
  border-radius: var(--radius);
  background: transparent;
  overflow: hidden;
  transition: opacity var(--transition);
  border: none;
}
.article-card:hover {
  opacity: 0.75;
  text-decoration: none;
}
.article-card img {
  aspect-ratio: 16 / 9;
  object-fit: cover;
  width: 100%;
  border-radius: var(--radius);
}
.article-card-placeholder {
  aspect-ratio: 16 / 9;
  background: var(--bg-subtle);
  border-radius: var(--radius);
}
.article-card-body {
  padding: 0.75rem 0;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}
.article-card-category {
  font-size: 0.6875rem;
  color: var(--accent);
  font-weight: 600;
  letter-spacing: 0.02em;
}
.article-card-body h3 {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--fg);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.article-card-body time {
  font-size: 0.75rem;
  color: var(--fg-muted);
}

/* ===== Top Page ===== */
.top-main {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 1.5rem;
}
.hero {
  padding: 4rem 1rem 3rem;
}
.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 3rem;
  align-items: center;
  max-width: var(--max-w);
  margin: 0 auto;
}
.hero-text {
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.hero h1 {
  font-size: 3.5rem;
  font-weight: 700;
  letter-spacing: -0.04em;
  color: var(--fg);
  margin-bottom: 1rem;
  line-height: 1.1;
}
.hero-text p {
  font-size: 1rem;
  color: var(--fg-muted);
  margin-bottom: 0;
  font-weight: 400;
  letter-spacing: 0.08em;
}
.hero-video {
  width: 100%;
}
.hero-video-wrap {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  border-radius: var(--radius);
  overflow: hidden;
  background: #000;
  box-shadow: 0 8px 32px rgba(0,0,0,0.12);
}
.hero-video-wrap iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: 0;
}
.hero-video-caption {
  margin-top: 0.75rem;
  font-size: 0.75rem;
  color: var(--fg-muted);
  opacity: 0.7;
}
.top-section {
  margin-bottom: 4rem;
}
.top-section h2 {
  font-size: 0.8125rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fg-muted);
}
.section-subtitle {
  font-size: 0.875rem;
  color: var(--fg-muted);
  margin-top: -1rem;
  margin-bottom: 1.5rem;
}

/* --- Textbook Thumbnail Cards --- */
.textbook-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}
.textbook-card {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.5rem 1.75rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--card);
  transition: background var(--transition), border-color var(--transition), box-shadow var(--transition);
  text-decoration: none;
  color: var(--fg);
  position: relative;
  flex-wrap: wrap;
}
.textbook-card:hover {
  text-decoration: none;
  background: var(--bg-subtle);
  border-color: var(--accent-light);
  box-shadow: 0 2px 12px rgba(99,102,241,0.08);
}
.textbook-card-badge {
  position: absolute;
  top: -0.5rem;
  left: 1.25rem;
  font-size: 0.6875rem;
  font-weight: 600;
  color: var(--accent);
  background: var(--card);
  padding: 0 0.5rem;
  letter-spacing: 0.02em;
}
.textbook-card-vocal { border-left: none; }
.textbook-card-vocal:hover { border-color: var(--accent-light); }
.textbook-card-composition { border-left: none; }
.textbook-card-composition:hover { border-color: var(--accent-light); }
.textbook-card-icon {
  font-size: 2rem;
  flex-shrink: 0;
}
.textbook-card-body {
  flex: 1;
  min-width: 0;
}
.textbook-card-body h3 {
  font-size: 0.9375rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}
.textbook-card-body p {
  font-size: 0.8rem;
  color: var(--fg-muted);
  line-height: 1.5;
}
.textbook-card-arrow {
  font-size: 1rem;
  color: var(--fg-muted);
  flex-shrink: 0;
  transition: transform var(--transition);
}
.textbook-card:hover .textbook-card-arrow {
  transform: translateX(4px);
}

/* --- Price Cards --- */
.price-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  align-items: start;
}
.price-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  text-align: center;
  position: relative;
}
.price-card-main {
  border-color: var(--fg);
}
.price-card-label {
  display: inline-block;
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.2rem 0.75rem;
  border-radius: 9999px;
  background: var(--bg-subtle);
  color: var(--fg-muted);
  margin-bottom: 0.75rem;
}
.price-card-main .price-card-label {
  background: var(--fg);
  color: #fff;
}
.price-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}
.price-card-price {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 1.25rem;
  line-height: 1.2;
  letter-spacing: -0.02em;
}
.price-yen {
  font-size: 1rem;
  font-weight: 600;
}
.price-unit {
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--fg-muted);
}
.price-card-features {
  list-style: none;
  text-align: left;
  margin-bottom: 1.5rem;
  font-size: 0.8125rem;
  color: var(--fg-muted);
}
.price-card-features li {
  padding: 0.375rem 0;
  padding-left: 1.25rem;
  position: relative;
}
.price-card-features li::before {
  content: "\2713";
  position: absolute;
  left: 0;
  color: var(--fg-muted);
  font-weight: 600;
}
.price-card-btn {
  display: inline-block;
  padding: 0.5rem 1.75rem;
  border-radius: 9999px;
  font-size: 0.8125rem;
  font-weight: 600;
  border: 1px solid var(--border);
  color: var(--fg);
  background: transparent;
  transition: all var(--transition);
  text-decoration: none;
}
.price-card-btn:hover {
  border-color: var(--fg);
  text-decoration: none;
}
.price-card-btn-primary {
  background: var(--fg);
  color: #fff;
  border-color: var(--fg);
}
.price-card-btn-primary:hover {
  opacity: 0.85;
}
.section-more {
  text-align: center;
  margin-top: 2rem;
}
.more-link {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--fg-muted);
  transition: color var(--transition);
}
.more-link:hover {
  color: var(--fg);
}

/* ===== Category Grid ===== */
.category-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.625rem;
}
.category-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: transparent;
  transition: background var(--transition);
}
.category-card:hover {
  background: var(--bg-subtle);
  text-decoration: none;
}
.category-card-name {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--fg);
}
.category-card-count {
  font-size: 0.75rem;
  color: var(--fg-muted);
}

/* ===== Static Pages ===== */
.static-main {
  max-width: var(--max-w-narrow);
  margin: 0 auto;
  padding: 3rem 1.5rem;
}
.static-main > h1 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 2.5rem;
  letter-spacing: -0.025em;
}
.static-content {
  background: transparent;
  padding: 0;
}
.prose h2 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
}
.prose h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-top: 2rem;
  margin-bottom: 0.5rem;
}
.prose p {
  margin-bottom: 1.25rem;
}
.prose table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
}
.prose th,
.prose td {
  text-align: left;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
}
.prose th {
  font-weight: 600;
  width: 30%;
  color: var(--fg-muted);
  font-size: 0.875rem;
}
.prose ul {
  padding-left: 1.25rem;
  margin-bottom: 1rem;
}
.prose li {
  margin-bottom: 0.375rem;
}

/* ===== Profile Page ===== */
.profile-header {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-bottom: 2.5rem;
}
.profile-photo {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}
.profile-intro h2 {
  font-size: 1.5rem;
  margin-top: 0;
  margin-bottom: 0.25rem;
}
.profile-subtitle {
  font-size: 0.875rem;
  color: var(--fg-muted);
  margin-bottom: 0;
}

/* ===== Page Hero ===== */
.page-hero {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-bottom: 2.5rem;
}
.page-hero-img {
  width: 200px;
  height: 140px;
  object-fit: cover;
  border-radius: var(--radius);
  flex-shrink: 0;
}
.page-lead {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.5;
}

/* ===== Info Grid (Lesson) ===== */
.info-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
  margin: 2rem 0;
}
.info-card {
  padding: 1.25rem;
  background: var(--bg-subtle);
  border-radius: var(--radius);
  font-size: 0.9375rem;
}

/* ===== Flow List (Lesson) ===== */
.flow-list {
  margin: 2rem 0;
}
.flow-item {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.25rem;
}
.flow-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
  width: 2rem;
  text-align: center;
}

/* ===== CTA Section ===== */
.cta-section {
  text-align: center;
  padding: 2.5rem;
  background: var(--bg-subtle);
  border-radius: var(--radius);
  margin: 2.5rem 0;
}
.cta-btn {
  display: inline-block;
  padding: 0.75rem 2rem;
  background: var(--fg);
  color: #fff;
  border-radius: 9999px;
  font-weight: 600;
  font-size: 0.875rem;
  transition: opacity var(--transition);
}
.cta-btn:hover {
  opacity: 0.85;
  text-decoration: none;
  color: #fff;
}

/* ===== FAQ List (Lesson) ===== */
.faq-list {
  margin: 2rem 0;
}
.faq-item {
  border-bottom: 1px solid var(--border);
  padding-bottom: 1.5rem;
  margin-bottom: 1.5rem;
}
.faq-item:last-child {
  border-bottom: none;
  margin-bottom: 0;
}
.faq-q {
  font-weight: 600;
  margin-bottom: 0.5rem;
}

/* ===== Note Box ===== */
.note-box {
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin: 2rem 0;
}
.note-box h3 {
  margin-top: 0;
  margin-bottom: 1rem;
}
.note-box ul {
  padding-left: 0;
  list-style: none;
}
.note-box li {
  font-size: 0.875rem;
  margin-bottom: 0.75rem;
}
.note-box li:last-child {
  margin-bottom: 0;
}

/* ===== Feature Grid (Webapp) ===== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin: 2rem 0;
}
.feature-card {
  background: var(--bg-subtle);
  border-radius: var(--radius);
  padding: 1.5rem;
}
.feature-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-top: 0.5rem;
  margin-bottom: 0.5rem;
}
.feature-card p {
  font-size: 0.875rem;
  color: var(--fg-muted);
  margin: 0;
}
.feature-icon {
  font-size: 1.5rem;
}

/* ===== Portfolio Grid (Webapp) ===== */
.portfolio-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin: 2rem 0;
}
.portfolio-card {
  background: var(--bg-subtle);
  border-radius: var(--radius);
  padding: 1.5rem;
}
.portfolio-card h3 {
  font-size: 1.125rem;
  font-weight: 700;
  margin-top: 0;
  margin-bottom: 0.25rem;
}
.portfolio-card ul {
  padding-left: 0;
  list-style: none;
}
.portfolio-card li {
  padding: 0.75rem;
  background: var(--card);
  border-radius: var(--radius);
  margin-bottom: 0.5rem;
  font-size: 0.875rem;
}
.portfolio-card li small {
  color: var(--fg-muted);
  font-size: 0.75rem;
}

/* ===== Tech Grid (Webapp) ===== */
.tech-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin: 2rem 0;
  background: var(--bg-subtle);
  padding: 1.5rem;
  border-radius: var(--radius);
}
.tech-grid h4 {
  font-size: 0.875rem;
  font-weight: 700;
  margin-top: 0;
  margin-bottom: 0.5rem;
}
.tech-grid p {
  font-size: 0.8125rem;
  color: var(--fg-muted);
  line-height: 1.8;
  margin: 0;
}

/* ===== Process Steps (Webapp) ===== */
.process-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin: 2rem 0;
}
.process-step {
  background: var(--bg-subtle);
  border-radius: var(--radius);
  padding: 1.5rem 1rem;
  text-align: center;
  position: relative;
}
.step-num {
  width: 2rem;
  height: 2rem;
  background: var(--fg);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.8125rem;
  margin: 0 auto 0.75rem;
}
.process-step h3 {
  font-size: 1rem;
  margin-top: 0;
  margin-bottom: 0.25rem;
}
.process-step > p {
  font-size: 0.8125rem;
  color: var(--fg-muted);
  margin-bottom: 0.5rem;
}
.process-step ul {
  text-align: left;
  padding-left: 1rem;
  list-style: disc;
}
.process-step li {
  font-size: 0.75rem;
  color: var(--fg-muted);
  margin-bottom: 0.25rem;
}

/* ===== Audio Page ===== */
.audio-hero {
  text-align: center;
  padding: 3rem 1rem;
  background: var(--bg-subtle);
  border-radius: var(--radius);
  margin-bottom: 2rem;
}
.audio-hero h2 {
  margin-top: 0;
  border: none;
}
.audio-section {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 1.5rem;
}
.audio-section-header {
  background: var(--bg-subtle);
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border);
}
.audio-section-header h3 {
  font-size: 1rem;
  font-weight: 700;
  margin: 0;
}
.audio-section-header p {
  font-size: 0.8125rem;
  color: var(--fg-muted);
  margin: 0.25rem 0 0;
}
.audio-section-body {
  padding: 1.5rem;
}
.audio-item {
  margin-bottom: 1.25rem;
}
.audio-item:last-child {
  margin-bottom: 0;
}
.audio-item h4 {
  font-size: 0.9375rem;
  font-weight: 600;
  margin: 0 0 0.25rem;
}
.audio-item p {
  font-size: 0.8125rem;
  color: var(--fg-muted);
  margin: 0 0 0.5rem;
}
.audio-item audio {
  width: 100%;
  height: 40px;
}
.range-guide {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.75rem;
  text-align: center;
  margin: 1rem 0;
}
.range-guide > div {
  padding: 0.75rem;
  border-radius: var(--radius);
  font-size: 0.8125rem;
}

/* ===== Textbook Layout ===== */
.textbook-layout {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem 3rem;
  display: flex;
  gap: 2.5rem;
}
.textbook-sidebar {
  width: 220px;
  flex-shrink: 0;
}
.textbook-sidebar-inner {
  position: sticky;
  top: 4rem;
}
.textbook-toc {
  background: transparent;
  border: none;
  padding: 0;
}
.textbook-toc h3 {
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fg-muted);
  margin: 0 0 0.75rem;
}
.textbook-toc ul {
  list-style: none;
  padding: 0;
  margin: 0;
}
.textbook-toc li a {
  display: block;
  padding: 0.375rem 0.5rem;
  font-size: 0.8125rem;
  border-radius: 0.25rem;
  color: var(--fg-muted);
  transition: all var(--transition);
}
.textbook-toc li a:hover {
  color: var(--fg);
  text-decoration: none;
}
.textbook-toc li.toc-chapter a {
  font-weight: 600;
  color: var(--fg);
}
.textbook-toc li.toc-section a {
  padding-left: 1rem;
  font-size: 0.75rem;
}
.textbook-sidebar-links {
  background: transparent;
  border: none;
  border-top: 1px solid var(--border);
  padding: 1rem 0 0;
  margin-top: 1rem;
}
.textbook-sidebar-links h3 {
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fg-muted);
  margin: 0 0 0.75rem;
}
.textbook-sidebar-links a {
  display: block;
  padding: 0.5rem 0.75rem;
  font-size: 0.8125rem;
  border-radius: var(--radius);
  margin-bottom: 0.375rem;
  transition: background var(--transition);
}
.textbook-sidebar-links a:hover {
  text-decoration: none;
}
.sidebar-link-textbook {
  background: #fffbeb;
  color: #92400e;
}
.sidebar-link-textbook:hover {
  background: #fef3c7;
}
.sidebar-link-practice {
  background: #eef2ff;
  color: #3730a3;
}
.sidebar-link-practice:hover {
  background: #e0e7ff;
}
.sidebar-link-composition {
  background: #f5f3ff;
  color: #5b21b6;
}
.sidebar-link-composition:hover {
  background: #ede9fe;
}
.sidebar-link-lesson {
  background: #f0fdf4;
  color: #166534;
}
.sidebar-link-lesson:hover {
  background: #dcfce7;
}
.textbook-main {
  flex: 1;
  min-width: 0;
}
.textbook-hero {
  text-align: center;
  padding: 3rem 1rem;
  border-radius: var(--radius);
  margin-bottom: 2.5rem;
}
.textbook-hero-vocal {
  background: var(--bg-subtle);
}
.textbook-hero-composition {
  background: var(--bg-subtle);
}
.textbook-hero h1 {
  margin: 0 0 0.5rem;
  font-size: 2rem;
  letter-spacing: -0.025em;
}
.textbook-hero p {
  color: var(--fg-muted);
  margin: 0;
}
.textbook-content {
  background: transparent;
  border: none;
  padding: 0;
}
.textbook-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-top: 3.5rem;
  margin-bottom: 1rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  position: relative;
  letter-spacing: -0.02em;
}
.textbook-content h2:first-child {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
}
.textbook-content h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
}
.textbook-content h4 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-top: 2rem;
  margin-bottom: 0.5rem;
}
.textbook-content p {
  margin-bottom: 1.5rem;
  line-height: 2;
}
.textbook-content blockquote {
  border-left: 2px solid var(--accent);
  margin: 2rem 0;
  padding: 0 1.5rem;
}
.textbook-content blockquote p {
  margin: 0;
  color: var(--fg-muted);
  font-style: italic;
}
.textbook-content ul, .textbook-content ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}
.textbook-content li {
  margin-bottom: 0.5rem;
}
.textbook-content strong {
  font-weight: 700;
}
.textbook-content hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 3rem 0;
}
.textbook-footer-cta {
  text-align: center;
  background: var(--fg);
  color: #fff;
  border-radius: var(--radius);
  padding: 2.5rem;
  margin-top: 3rem;
}
.textbook-footer-cta h3 {
  color: #fff;
  margin: 0 0 0.5rem;
  border: none;
}
.textbook-footer-cta p {
  color: rgba(255,255,255,0.6);
  margin: 0 0 1.25rem;
}
.textbook-footer-cta a {
  display: inline-block;
  background: #fff;
  color: var(--fg);
  padding: 0.75rem 2rem;
  border-radius: 9999px;
  font-weight: 600;
  font-size: 0.875rem;
}
.textbook-footer-cta a:hover {
  opacity: 0.9;
  text-decoration: none;
}
.textbook-mobile-toc {
  display: none;
  margin-bottom: 1.5rem;
}
.textbook-mobile-toc summary {
  padding: 0.75rem 1rem;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.875rem;
  cursor: pointer;
}
.textbook-mobile-toc nav {
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-top: none;
  border-radius: 0 0 var(--radius) var(--radius);
}
.textbook-mobile-toc ul {
  list-style: none;
  padding: 0;
  margin: 0;
}
.textbook-mobile-toc li a {
  display: block;
  padding: 0.375rem 0;
  font-size: 0.8125rem;
  color: var(--fg-muted);
}
.textbook-mobile-toc li.toc-chapter a {
  font-weight: 600;
  color: var(--fg);
}
.textbook-mobile-toc li.toc-section a {
  padding-left: 1rem;
  font-size: 0.75rem;
}
.reading-progress {
  position: sticky;
  top: 0;
  z-index: 40;
  height: 2px;
  background: transparent;
}
.reading-progress-bar {
  height: 100%;
  background: var(--fg);
  width: 0;
  transition: width 0.15s;
}

/* ===== Interactive Music Components ===== */

/* --- InlinePiano --- */
.music-piano {
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin: 2rem 0;
  text-align: center;
  overflow-x: auto;
}
.music-piano-title {
  font-weight: 600;
  font-size: 0.875rem;
  margin-bottom: 0.75rem;
}
.music-piano-caption {
  font-size: 0.75rem;
  color: var(--fg-muted);
  margin-top: 0.75rem;
}
.music-piano-legend {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-top: 0.75rem;
  font-size: 0.7rem;
  color: var(--fg-muted);
}
.legend-item {
  display: flex;
  align-items: center;
  gap: 4px;
}
.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
}
.legend-dot.scale { background: #22c55e; }
.legend-dot.root { background: #f97316; }
.legend-tap { font-style: italic; }

.piano-keyboard {
  position: relative;
  display: inline-block;
  margin: 0 auto;
}
.piano-white-layer {
  display: flex;
  gap: 2px;
}
.piano-black-layer {
  position: absolute;
  top: 0;
  left: 0;
  pointer-events: none;
}
.piano-key {
  cursor: pointer;
  position: relative;
  user-select: none;
  -webkit-user-select: none;
  transition: background 0.08s, transform 0.05s;
}
.piano-key-white {
  width: 34px;
  height: 100px;
  background: #fff;
  border: 1px solid #d4d4d8;
  border-radius: 0 0 4px 4px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-end;
  padding-bottom: 6px;
}
.piano-key-white.in-scale {
  background: #dcfce7;
  border-color: #86efac;
}
.piano-key-white.is-root {
  background: #ffedd5;
  border-color: #fdba74;
}
.piano-key-white.playing {
  background: #c7d2fe;
  transform: translateY(2px);
}
.piano-key-black {
  width: 22px;
  height: 62px;
  background: #27272a;
  border-radius: 0 0 3px 3px;
  position: absolute;
  z-index: 2;
  pointer-events: auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-end;
  padding-bottom: 4px;
}
.piano-key-black.in-scale {
  background: #166534;
}
.piano-key-black.is-root {
  background: #c2410c;
}
.piano-key-black.playing {
  background: #6366f1;
  transform: translateY(2px);
}
.piano-degree {
  font-size: 0.6rem;
  font-weight: 700;
  color: rgba(0,0,0,0.5);
  pointer-events: none;
}
.piano-key-black .piano-degree {
  color: rgba(255,255,255,0.8);
}
.piano-note-name {
  font-size: 0.55rem;
  color: var(--fg-muted);
  pointer-events: none;
}

/* --- ChordProgressionPlayer --- */
.music-chord {
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin: 2rem 0;
}
.music-chord-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}
.music-chord-title {
  font-weight: 600;
  font-size: 0.875rem;
}
.music-chord-key-control {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.8rem;
}
.music-chord-key-label {
  color: var(--fg-muted);
}
.music-chord-key-select {
  padding: 0.25rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 0.8rem;
  background: var(--card);
  cursor: pointer;
}
.music-chord-preset-bar {
  display: flex;
  gap: 0.375rem;
  flex-wrap: wrap;
  margin-bottom: 0.75rem;
}
.music-chord-preset-btn {
  padding: 0.25rem 0.625rem;
  border: 1px solid var(--border);
  border-radius: 9999px;
  font-size: 0.7rem;
  background: transparent;
  cursor: pointer;
  transition: all var(--transition);
}
.music-chord-preset-btn:hover {
  border-color: var(--fg);
  color: var(--fg);
}
.music-chord-preset-btn.active {
  background: var(--fg);
  color: #fff;
  border-color: var(--fg);
}
.music-chord-buttons {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 0.75rem;
}
.music-chord-btn {
  padding: 0.625rem 1.25rem;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  min-width: 60px;
}
.music-chord-btn:hover {
  border-color: var(--fg);
}
.music-chord-btn.active {
  border-color: var(--fg);
  background: var(--bg-subtle);
}
.chord-name {
  font-size: 1rem;
  font-weight: 700;
}
.chord-degree {
  font-size: 0.65rem;
  color: var(--fg-muted);
}

/* Mini piano for chord visualization */
.music-chord-mini-piano {
  margin-top: 0.5rem;
}
.mini-piano-wrapper {
  position: relative;
  display: inline-block;
}
.mini-piano-white-layer {
  display: flex;
  gap: 1px;
}
.mini-piano-black-layer {
  position: absolute;
  top: 0;
  left: 0;
  pointer-events: none;
}
.mini-piano-key-white {
  width: 24px;
  height: 48px;
  background: #f4f4f5;
  border: 1px solid #d4d4d8;
  border-radius: 0 0 3px 3px;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding-bottom: 2px;
  transition: background var(--transition);
}
.mini-piano-key-black {
  width: 16px;
  height: 30px;
  background: #3f3f46;
  border-radius: 0 0 2px 2px;
  position: absolute;
  z-index: 1;
  transition: background var(--transition);
}
.mini-piano-key-white.chord-active {
  background: #c7d2fe;
  border-color: #818cf8;
}
.mini-piano-key-black.chord-active {
  background: #6366f1;
}
.mini-piano-note {
  font-size: 0.5rem;
  color: var(--fg-muted);
}

/* --- BeatPlayer --- */
.music-beat {
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin: 2rem 0;
}
.music-beat-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}
.music-beat-title {
  font-weight: 600;
  font-size: 0.875rem;
}
.music-beat-bpm {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.8rem;
  color: var(--fg-muted);
}
.music-beat-bpm-btn {
  width: 28px;
  height: 28px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--card);
  cursor: pointer;
  font-size: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: border-color var(--transition);
}
.music-beat-bpm-btn:hover {
  border-color: var(--fg);
}
.music-beat-bpm-value {
  font-weight: 600;
  min-width: 2em;
  text-align: center;
  color: var(--fg);
}
.music-beat-pattern-bar {
  display: flex;
  gap: 0.375rem;
  flex-wrap: wrap;
  margin-bottom: 0.75rem;
}
.music-beat-pattern-btn {
  padding: 0.25rem 0.625rem;
  border: 1px solid var(--border);
  border-radius: 9999px;
  font-size: 0.7rem;
  background: transparent;
  cursor: pointer;
  transition: all var(--transition);
}
.music-beat-pattern-btn:hover {
  border-color: var(--fg);
  color: var(--fg);
}
.music-beat-pattern-btn.active {
  background: var(--fg);
  color: #fff;
  border-color: var(--fg);
}
/* Drum machine grid */
.music-beat-grid {
  margin-bottom: 0.75rem;
  overflow-x: auto;
}
.beat-grid-row {
  display: grid;
  grid-template-columns: 36px repeat(8, 1fr);
  gap: 4px;
  margin-bottom: 4px;
}
.beat-grid-header {
  margin-bottom: 2px;
}
.beat-grid-label {
  font-size: 0.65rem;
  font-weight: 700;
  color: var(--fg-muted);
  display: flex;
  align-items: center;
  justify-content: center;
  user-select: none;
}
.beat-grid-label-kick { color: #dc2626; }
.beat-grid-label-snare { color: #d97706; }
.beat-grid-label-hihat { color: #71717a; }
.beat-grid-step-num {
  font-size: 0.6rem;
  color: var(--fg-muted);
  text-align: center;
}
.beat-grid-cell {
  height: 28px;
  border-radius: 4px;
  background: #f4f4f5;
  border: 1px solid var(--border);
  transition: background 0.1s, border-color 0.1s, box-shadow 0.1s;
}
.beat-grid-cell.on.beat-cell-kick {
  background: #fecaca;
  border-color: #f87171;
}
.beat-grid-cell.on.beat-cell-snare {
  background: #fef3c7;
  border-color: #fbbf24;
}
.beat-grid-cell.on.beat-cell-hihat {
  background: #e4e4e7;
  border-color: #a1a1aa;
}
.beat-grid-cell.current {
  box-shadow: inset 0 0 0 2px var(--accent);
}
.beat-grid-cell.on.current.beat-cell-kick {
  background: #ef4444;
  border-color: #ef4444;
}
.beat-grid-cell.on.current.beat-cell-snare {
  background: #f59e0b;
  border-color: #f59e0b;
}
.beat-grid-cell.on.current.beat-cell-hihat {
  background: #a1a1aa;
  border-color: #71717a;
}
.music-beat-controls {
  text-align: center;
}
.music-beat-play-btn {
  padding: 0.5rem 1.5rem;
  border: 1px solid var(--fg);
  border-radius: 9999px;
  background: transparent;
  cursor: pointer;
  font-size: 0.8125rem;
  font-weight: 600;
  transition: all var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
}
.music-beat-play-btn:hover {
  background: var(--fg);
  color: #fff;
}
.music-beat-play-btn.active {
  background: var(--fg);
  color: #fff;
}
.play-icon, .stop-icon { font-size: 0.75rem; }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .article-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
  }
  .category-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .related-grid {
    grid-template-columns: 1fr;
  }
  .post-title {
    font-size: 1.5rem;
  }
  .hero {
    padding: 2rem 1rem;
  }
  .hero-inner {
    grid-template-columns: 1fr;
    gap: 2rem;
    text-align: center;
  }
  .hero h1 {
    font-size: 2.25rem;
  }
  .hero-video-caption {
    text-align: center;
  }
  .profile-header {
    flex-direction: column;
    text-align: center;
  }
  .thumbnaillist {
    grid-template-columns: 1fr;
  }
  .page-hero {
    flex-direction: column;
  }
  .page-hero-img {
    width: 100%;
    height: auto;
    max-height: 200px;
  }
  .info-grid {
    grid-template-columns: 1fr;
  }
  .feature-grid {
    grid-template-columns: 1fr;
  }
  .portfolio-grid {
    grid-template-columns: 1fr;
  }
  .tech-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .process-steps {
    grid-template-columns: repeat(2, 1fr);
  }
  .range-guide {
    grid-template-columns: 1fr;
  }
  .textbook-sidebar {
    display: none;
  }
  .textbook-mobile-toc {
    display: block;
  }
  .textbook-layout {
    flex-direction: column;
  }
  .textbook-hero h1 {
    font-size: 1.5rem;
  }
  .textbook-cards { grid-template-columns: 1fr; }
  .price-cards { grid-template-columns: 1fr; }
  /* Music components responsive */
  .piano-key-white { width: 26px; height: 76px; }
  .piano-key-black { width: 18px; height: 48px; }
  .music-chord-header { flex-direction: column; align-items: flex-start; gap: 0.5rem; }
  .music-beat-header { flex-direction: column; align-items: flex-start; gap: 0.5rem; }
  .music-beat-grid { gap: 4px; }
  .music-piano-legend { flex-wrap: wrap; }
}
@media (max-width: 480px) {
  .article-grid {
    grid-template-columns: 1fr;
  }
  .category-grid {
    grid-template-columns: 1fr;
  }
  .header-inner {
    padding: 0.75rem 1rem;
  }
  .category-bar-inner {
    padding: 0.5rem 1rem;
  }
}