:root {
  --paper: #f5f7f2;
  --paper-strong: #ffffff;
  --ink: #121213;
  --ink-soft: #303036;
  --muted: #65706d;
  --line: rgba(18, 18, 19, 0.16);
  --coral: #e6422e;
  --cyan: #0ea5b7;
  --green: #0f8c5a;
  --yellow: #f6b331;
  --blue: #3454d1;
  --pink: #d9488b;
  --shadow: 0 16px 42px rgba(18, 18, 19, 0.12);
  --font-display: "Microsoft YaHei UI", "Microsoft YaHei", "Georgia", serif;
  --font-body: "Aptos", "Segoe UI", "Microsoft YaHei", sans-serif;
  --page-max: 1220px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  margin: 0;
  background:
    linear-gradient(90deg, rgba(18, 18, 19, 0.05) 1px, transparent 1px),
    linear-gradient(180deg, rgba(14, 165, 183, 0.12), transparent 440px),
    var(--paper);
  background-size: 42px 42px, 100% 100%;
  color: var(--ink);
  font-family: var(--font-body);
}

button,
input,
select {
  font: inherit;
}

button {
  color: inherit;
  cursor: pointer;
}

a {
  color: inherit;
  text-decoration: none;
}

h1,
h2,
h3,
h4,
p {
  margin-top: 0;
}

@keyframes pageRise {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes notebookFloat {
  0%,
  100% {
    transform: translateX(var(--notebook-shift, 0)) rotate(5deg) translateY(0);
  }
  50% {
    transform: translateX(var(--notebook-shift, 0)) rotate(3deg) translateY(-10px);
  }
}

@keyframes tileTap {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-8px);
  }
}

@keyframes cardPeelIn {
  from {
    opacity: 0;
    transform: translateY(18px) scale(0.985);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

.theory-site {
  overflow: hidden;
}

.site-header,
.hero,
.product-row,
.section {
  width: min(var(--page-max), 100%);
  margin: 0 auto;
  padding-left: 24px;
  padding-right: 24px;
}

.site-header {
  min-height: 74px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding-top: 16px;
  padding-bottom: 10px;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 900;
}

.brand-note {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border: 2px solid var(--ink);
  border-radius: 50%;
  background: var(--paper-strong);
  color: var(--coral);
  box-shadow: 0 3px 0 var(--ink);
  font-size: 25px;
  line-height: 1;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px;
}

.site-nav a,
.pill-button,
.quiet-link {
  min-height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 14px;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: var(--paper-strong);
  font-size: 14px;
  font-weight: 900;
  box-shadow: 0 2px 0 rgba(18, 18, 19, 0.2);
  transition: transform 160ms ease, border-color 160ms ease, background 160ms ease;
}

.site-nav a:hover,
.pill-button:hover,
.quiet-link:hover {
  transform: translateY(-2px);
  border-color: var(--coral);
  background: #fff9d7;
}

.hero {
  position: relative;
  min-height: 720px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 460px);
  gap: 54px;
  align-items: center;
  padding-top: 26px;
  padding-bottom: 86px;
}

.hero-copy {
  position: relative;
  z-index: 2;
  animation: pageRise 620ms ease both;
}

.marker-caption,
.scribble-caption {
  margin-bottom: 16px;
  color: var(--coral);
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 900;
  line-height: 1.25;
}

h1 {
  max-width: 760px;
  margin-bottom: 24px;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: clamp(48px, 8vw, 96px);
  font-weight: 900;
  line-height: 1.02;
  letter-spacing: 0;
}

h2 {
  margin-bottom: 18px;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: clamp(34px, 5vw, 54px);
  font-weight: 900;
  line-height: 1.08;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 12px;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: clamp(32px, 4vw, 44px);
  font-weight: 900;
  line-height: 1.08;
  letter-spacing: 0;
}

h4 {
  margin: 8px 0 10px;
  font-family: var(--font-display);
  font-size: 28px;
  line-height: 1.12;
}

p {
  color: var(--ink-soft);
  font-size: 18px;
  line-height: 1.58;
}

.intro-copy {
  max-width: 680px;
  margin-bottom: 24px;
  font-size: 21px;
}

.intro-copy span {
  color: var(--coral);
  font-weight: 900;
  text-decoration: underline;
  text-decoration-color: var(--yellow);
  text-decoration-thickness: 5px;
  text-underline-offset: 4px;
}

.stat-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 28px;
}

.stat-row span {
  min-height: 46px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: var(--paper-strong);
  box-shadow: 0 2px 0 rgba(18, 18, 19, 0.22);
  color: var(--ink-soft);
  font-weight: 900;
}

.stat-row strong {
  color: var(--blue);
  font-family: var(--font-display);
  font-size: 26px;
  line-height: 1;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 14px;
  margin-bottom: 12px;
}

.pill-button {
  min-width: 136px;
  background: var(--ink);
  color: #ffffff;
}

.quiet-link {
  border-color: var(--line);
  box-shadow: none;
}

.preorder-note {
  max-width: 560px;
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  font-weight: 800;
}

.hero-product {
  position: relative;
  min-height: 580px;
  animation: pageRise 740ms ease 100ms both;
}

.theory-notebook {
  position: absolute;
  right: 8px;
  top: 64px;
  width: min(390px, 88vw);
  min-height: 486px;
  animation: notebookFloat 5.4s ease-in-out 800ms infinite;
}

.notebook-cover {
  position: relative;
  min-height: 486px;
  padding: 34px 28px 28px;
  overflow: hidden;
  border: 2px solid var(--ink);
  border-radius: 8px;
  background:
    repeating-linear-gradient(90deg, rgba(18, 18, 19, 0.08) 0 1px, transparent 1px 32px),
    linear-gradient(160deg, #c9f4ff 0%, #fffdfa 48%, #ffe866 100%);
  box-shadow: 16px 16px 0 rgba(18, 18, 19, 0.15);
}

.notebook-cover::before {
  content: "";
  position: absolute;
  inset: 16px;
  border: 1.5px solid rgba(18, 18, 19, 0.18);
  border-radius: 8px;
  pointer-events: none;
}

.staff-lines,
.score-card-visual {
  position: absolute;
  left: 28px;
  right: 28px;
  bottom: 118px;
  min-height: 118px;
}

.staff-lines span,
.score-card-visual span {
  display: block;
  height: 2px;
  margin-top: 18px;
  background: rgba(18, 18, 19, 0.68);
}

.staff-lines b {
  position: absolute;
  left: var(--x);
  top: var(--y);
  width: 22px;
  height: 17px;
  border-radius: 50%;
  background: var(--coral);
  transform: rotate(-18deg);
}

.staff-lines b::after {
  content: "";
  position: absolute;
  right: -5px;
  bottom: 8px;
  width: 3px;
  height: 58px;
  background: var(--ink);
  border-radius: 999px;
}

.name-sticker {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 10px;
  padding: 16px;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: var(--paper-strong);
  box-shadow: 0 3px 0 rgba(18, 18, 19, 0.2);
}

.name-sticker > span,
.label-field {
  color: var(--coral);
  font-size: 13px;
  font-weight: 900;
  text-transform: uppercase;
}

.name-sticker strong {
  font-family: var(--font-display);
  font-size: 32px;
  line-height: 1.05;
}

.sticker-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.sticker-grid p {
  min-width: 0;
  display: grid;
  gap: 4px;
  margin: 0;
  padding-top: 9px;
  border-top: 1.5px solid var(--line);
}

.sticker-grid span {
  color: var(--muted);
  font-size: 12px;
  font-weight: 900;
}

.sticker-grid b {
  color: var(--ink);
  font-size: 16px;
  line-height: 1.2;
  overflow-wrap: anywhere;
}

.cover-note {
  position: absolute;
  left: 28px;
  right: 28px;
  bottom: 28px;
  margin: 0;
  color: var(--ink);
  font-size: 16px;
  font-weight: 900;
}

.rhythm-tiles {
  position: absolute;
  left: 0;
  bottom: 96px;
  display: grid;
  grid-template-columns: 54px;
  gap: 10px;
}

.rhythm-tiles span {
  width: 54px;
  height: 54px;
  display: grid;
  place-items: center;
  border: 2px solid var(--ink);
  border-radius: 8px;
  background: var(--paper-strong);
  box-shadow: 0 4px 0 rgba(18, 18, 19, 0.2);
  color: var(--blue);
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 900;
  animation: tileTap 1.8s ease-in-out infinite;
}

.rhythm-tiles span:nth-child(2) {
  animation-delay: 120ms;
  color: var(--coral);
}

.rhythm-tiles span:nth-child(3) {
  animation-delay: 240ms;
  color: var(--green);
}

.rhythm-tiles span:nth-child(4) {
  animation-delay: 360ms;
  color: var(--pink);
}

.scribble-caption {
  position: absolute;
  left: 26px;
  top: 26px;
  margin: 0;
  transform: rotate(-8deg);
}

.product-row {
  display: grid;
  grid-template-columns: minmax(240px, 1fr) minmax(280px, 430px) minmax(220px, 0.8fr);
  gap: 34px;
  align-items: center;
  padding-top: 6px;
  padding-bottom: 92px;
}

.showcase-copy p:last-child {
  margin-bottom: 0;
}

.showcase-object {
  position: relative;
  min-height: 260px;
  border: 2px solid var(--ink);
  border-radius: 8px;
  background: var(--paper-strong);
  box-shadow: var(--shadow);
}

.score-card-visual {
  position: relative;
  inset: auto;
  padding: 40px 24px;
  background:
    linear-gradient(135deg, rgba(52, 84, 209, 0.16), transparent 62%),
    var(--paper-strong);
}

.score-card-visual b {
  position: absolute;
  width: 20px;
  height: 16px;
  border-radius: 50%;
  background: var(--cyan);
}

.score-card-visual b:nth-of-type(1) {
  left: 24%;
  top: 54%;
}

.score-card-visual b:nth-of-type(2) {
  left: 48%;
  top: 36%;
  background: var(--coral);
}

.score-card-visual b:nth-of-type(3) {
  left: 72%;
  top: 62%;
  background: var(--green);
}

.quiz-card-visual {
  display: grid;
  place-items: center;
  align-content: center;
  gap: 14px;
  background:
    repeating-linear-gradient(0deg, rgba(18, 18, 19, 0.04) 0 12px, transparent 12px 24px),
    #fff6fd;
}

.quiz-card-visual span {
  width: 76px;
  height: 76px;
  display: grid;
  place-items: center;
  border: 2px solid var(--ink);
  border-radius: 50%;
  background: var(--pink);
  color: #ffffff;
  font-family: var(--font-display);
  font-size: 42px;
  font-weight: 900;
}

.quiz-card-visual i {
  width: min(170px, 70%);
  height: 12px;
  display: block;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: var(--paper-strong);
}

.cover-gallery-shell {
  min-height: 700px;
  display: block;
  overflow: hidden;
  background:
    radial-gradient(circle at 50% 20%, rgba(255, 255, 255, 0.82), transparent 42%),
    linear-gradient(180deg, #fbfaf6 0%, #efece3 100%);
}

.showcase-object.cover-gallery-shell {
  border: 0;
  border-radius: 0;
  background: transparent;
  box-shadow: none;
}

.circular-gallery {
  position: absolute;
  inset: 0;
  overflow: hidden;
  cursor: grab;
  touch-action: pan-y;
  user-select: none;
  perspective: 820px;
  perspective-origin: 50% 44%;
}

.circular-gallery.is-dragging {
  cursor: grabbing;
}

.circular-gallery:focus-visible {
  outline: 2px solid rgba(18, 18, 19, 0.74);
  outline-offset: -8px;
}

.circular-gallery-stage {
  position: absolute;
  inset: 0;
  transform-style: preserve-3d;
}

.circular-gallery-card {
  --x: 50%;
  --y: 50%;
  --rotate-y: 0deg;
  --rotate-z: 0deg;
  --z: 0px;
  --scale: 1;
  --alpha: 1;
  position: absolute;
  left: 0;
  top: 50%;
  width: clamp(320px, 38vw, 380px);
  margin: 0;
  border: 1.5px solid rgba(18, 18, 19, 0.86);
  border-radius: 18px;
  background: #f3efe4;
  box-shadow:
    0 34px 50px rgba(18, 18, 19, 0.20),
    0 4px 0 rgba(18, 18, 19, 0.10);
  opacity: var(--alpha);
  overflow: hidden;
  transform:
    translate3d(calc(var(--x) - 50%), calc(var(--y) - 50%), var(--z))
    rotateY(var(--rotate-y))
    rotateZ(var(--rotate-z))
    scale(var(--scale));
  transform-origin: center center;
  backface-visibility: hidden;
  transition: box-shadow 160ms ease, opacity 160ms ease;
  will-change: transform, opacity;
}

.circular-gallery-card.is-front {
  border-color: rgba(18, 18, 19, 0.95);
  box-shadow:
    0 42px 70px rgba(18, 18, 19, 0.26),
    0 0 0 8px rgba(255, 255, 255, 0.42);
}

.gallery-card-media {
  position: relative;
  aspect-ratio: 416 / 554;
  overflow: hidden;
  border-bottom: 1.5px solid rgba(18, 18, 19, 0.72);
  background: var(--accent);
}

.gallery-card-media::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  z-index: 1;
  height: 10px;
  background: var(--accent);
}

.circular-gallery-card img {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
  object-position: center center;
  pointer-events: none;
}

.gallery-card-copy {
  display: grid;
  gap: 5px;
  padding: 13px 18px 15px;
  color: #3c3128;
}

.gallery-card-copy div {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}

.gallery-card-copy strong {
  color: #2f261e;
  font-family: var(--font-display);
  font-size: clamp(22px, 2.7vw, 29px);
  font-weight: 900;
  line-height: 1;
}

.gallery-card-copy span {
  color: rgba(47, 38, 30, 0.62);
  font-size: 14px;
}

.gallery-card-copy p {
  display: -webkit-box;
  margin: 0;
  overflow: hidden;
  color: #5b5148;
  font-size: 14.5px;
  line-height: 1.35;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
}

.gallery-card-copy em {
  color: rgba(47, 38, 30, 0.58);
  font-size: 12.5px;
  font-style: normal;
  line-height: 1.25;
}

.gallery-hint {
  display: none;
}

.section {
  padding-top: 18px;
  padding-bottom: 96px;
}

.section-heading {
  max-width: 780px;
  margin-bottom: 28px;
}

.section-heading.wide {
  max-width: 980px;
}

.section-heading p:last-child {
  margin-bottom: 0;
}

.level-board {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 14px;
}

.level-label,
.resource-label,
.lesson-card {
  border: 2px solid var(--ink);
  border-radius: 8px;
  background: var(--paper-strong);
  box-shadow: var(--shadow);
}

.level-label {
  position: relative;
  min-height: 260px;
  display: grid;
  align-content: end;
  gap: 12px;
  padding: 18px;
  text-align: left;
  isolation: isolate;
  overflow: hidden;
  animation: pageRise 420ms ease both;
  transition: transform 160ms ease, box-shadow 160ms ease, background 160ms ease;
}

.level-label::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    linear-gradient(145deg, color-mix(in srgb, var(--accent) 30%, transparent), transparent 56%),
    repeating-linear-gradient(90deg, rgba(18, 18, 19, 0.06) 0 1px, transparent 1px 26px);
  opacity: 0.86;
}

.level-label:hover,
.level-label:focus-visible,
.level-label.is-active,
.resource-label:hover,
.resource-label:focus-visible,
.resource-label.is-active {
  outline: none;
  transform: translateY(-4px);
  box-shadow: 0 24px 46px rgba(18, 18, 19, 0.16);
}

.level-label.is-active {
  background: #fff9d7;
}

.level-kicker {
  width: max-content;
  padding: 5px 8px;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: var(--accent);
  color: #ffffff;
  font-size: 12px;
  font-weight: 900;
}

.level-label strong {
  font-family: var(--font-display);
  font-size: 42px;
  line-height: 1;
}

.level-label small {
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.38;
}

.level-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.level-meta em {
  padding: 5px 7px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.72);
  color: var(--muted);
  font-size: 12px;
  font-style: normal;
  font-weight: 900;
}

.filters {
  display: grid;
  grid-template-columns: minmax(220px, 1.2fr) minmax(180px, 0.8fr) minmax(180px, 0.8fr);
  gap: 12px;
  margin-bottom: 18px;
}

.filters label {
  display: grid;
  gap: 7px;
}

.filters span {
  color: var(--muted);
  font-size: 13px;
  font-weight: 900;
}

.filters input,
.filters select {
  width: 100%;
  min-height: 48px;
  padding: 0 12px;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: var(--paper-strong);
  color: var(--ink);
  box-shadow: 0 2px 0 rgba(18, 18, 19, 0.16);
}

.filters input:focus,
.filters select:focus {
  border-color: var(--blue);
  outline: 3px solid rgba(52, 84, 209, 0.16);
}

.catalog-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 16px;
}

.catalog-head strong {
  display: block;
  margin-bottom: 4px;
  font-family: var(--font-display);
  font-size: 28px;
  line-height: 1.1;
}

.catalog-head p {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  font-weight: 800;
}

.tag-cloud,
.tag-row {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
}

.tag-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 28px;
  padding: 5px 8px;
  border: 1.2px solid var(--line);
  border-radius: 8px;
  background: #f9fbff;
  color: var(--ink-soft);
  font-size: 12px;
  font-weight: 900;
}

button.tag-chip:hover,
button.tag-chip:focus-visible {
  border-color: var(--coral);
  outline: none;
  background: #fff9d7;
}

.tag-chip em {
  color: var(--blue);
  font-style: normal;
}

.resource-label-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 12px;
}

.resource-label {
  min-height: 270px;
  display: grid;
  align-content: start;
  gap: 10px;
  padding: 16px;
  text-align: left;
  transition: transform 160ms ease, box-shadow 160ms ease, border-color 160ms ease;
}

.resource-label.is-active {
  border-color: var(--blue);
  background: #f9fbff;
}

.roll-number {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border: 1.5px solid var(--ink);
  border-radius: 50%;
  background: var(--yellow);
  color: var(--ink);
  font-weight: 900;
}

.resource-label strong {
  font-family: var(--font-display);
  font-size: 25px;
  line-height: 1.08;
}

.resource-label small {
  color: var(--muted);
  font-size: 13px;
  font-weight: 900;
  line-height: 1.35;
}

.resource-label p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.48;
}

.empty-note {
  min-height: 200px;
  display: grid;
  align-content: center;
  gap: 8px;
  padding: 18px;
  border: 2px dashed var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.68);
  color: var(--muted);
}

.empty-note strong {
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 28px;
}

.lesson-section {
  display: grid;
  grid-template-columns: minmax(240px, 0.34fr) minmax(0, 1fr);
  gap: 54px;
  align-items: start;
  padding-bottom: 116px;
}

.lesson-card {
  display: grid;
  grid-template-columns: minmax(280px, 0.42fr) minmax(0, 1fr);
  gap: 0;
  overflow: hidden;
  background: #fff8f1;
}

.lesson-cover {
  min-height: 100%;
  display: grid;
  align-content: start;
  gap: 18px;
  padding: 32px;
  background:
    linear-gradient(155deg, color-mix(in srgb, var(--accent) 17%, transparent), transparent 58%),
    #fff8f1;
  border-right: 2px solid var(--ink);
}

.lesson-cover h3,
.lesson-cover p {
  margin-bottom: 0;
}

.lesson-cover p {
  color: var(--ink-soft);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 20px;
  line-height: 1.35;
}

.lesson-fields {
  grid-template-columns: 1fr;
}

.song-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.lesson-main {
  min-width: 0;
  display: grid;
  align-content: start;
}

.lesson-course-strip {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  padding: 18px;
  border-bottom: 2px solid var(--ink);
  background: #fffdf8;
}

.lesson-course-strip button {
  min-width: 0;
  min-height: 116px;
  display: grid;
  align-content: space-between;
  gap: 8px;
  padding: 12px;
  border: 1.5px solid var(--line);
  border-radius: 8px;
  background:
    linear-gradient(145deg, color-mix(in srgb, var(--accent) 18%, transparent), transparent 70%),
    #ffffff;
  color: var(--ink);
  text-align: left;
  transition: transform 160ms ease, border-color 160ms ease, box-shadow 160ms ease;
}

.lesson-course-strip button:hover,
.lesson-course-strip button:focus-visible,
.lesson-course-strip button.is-active {
  border-color: var(--ink);
  box-shadow: 0 14px 28px rgba(18, 18, 19, 0.12);
  outline: none;
  transform: translateY(-2px);
}

.lesson-course-strip span {
  color: var(--coral);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 28px;
  font-weight: 900;
  line-height: 1;
}

.lesson-course-strip strong {
  font-size: 15px;
  line-height: 1.2;
}

.lesson-course-strip small {
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
}

.lesson-tabs {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  border-top: 0;
  border-bottom: 2px solid var(--ink);
}

.lesson-tabs button {
  min-height: 58px;
  border: 0;
  border-right: 1.5px solid var(--line);
  background: #fff8f1;
  color: var(--ink);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 19px;
  font-weight: 900;
}

.lesson-tabs button:last-child {
  border-right: 0;
}

.lesson-tabs button:hover,
.lesson-tabs button:focus-visible,
.lesson-tabs button.is-active {
  outline: none;
  background: var(--ink);
  color: #ffffff;
}

.lesson-content-stack {
  position: relative;
  min-width: 0;
}

.lesson-pane {
  min-width: 0;
  min-height: 520px;
  padding: 28px 32px 34px;
  background: #fffdf8;
}

.lesson-content-stack > .lesson-pane:not(.is-parked) {
  position: relative;
  z-index: 1;
}

.lesson-metronome-pane.is-parked {
  position: absolute;
  inset: 0;
  width: 100%;
  height: clamp(640px, 82vh, 820px);
  padding: 0;
  opacity: 0;
  animation: none;
  pointer-events: none;
  z-index: 0;
}

.lesson-metronome-shell {
  overflow: hidden;
  min-width: 0;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: #101012;
  box-shadow: 0 16px 28px rgba(18, 18, 19, 0.14);
}

.lesson-metronome-frame {
  display: block;
  width: 100%;
  height: clamp(640px, 82vh, 820px);
  border: 0;
  background: #101012;
}

.lesson-metronome-pane.is-parked .lesson-metronome-shell,
.lesson-metronome-pane.is-parked .lesson-metronome-frame {
  width: 100%;
  height: 100%;
}

.lesson-metronome-pane.is-parked .lesson-metronome-shell {
  border: 0;
  border-radius: 0;
  box-shadow: none;
}

.audio-workbench,
.audio-player-frame {
  min-width: 0;
}

.audio-player-frame {
  display: grid;
  gap: 18px;
  padding: 18px;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: #ffffff;
}

.audio-version-head {
  display: flex;
  justify-content: space-between;
  gap: 16px;
}

.audio-version-head span {
  color: var(--coral);
  font-size: 12px;
  font-weight: 900;
  text-transform: uppercase;
}

.audio-version-head strong {
  display: block;
  margin-top: 6px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 28px;
}

.audio-version-head em {
  color: var(--muted);
  font-size: 14px;
  font-style: normal;
}

.audio-speed-player-shell {
  min-height: 180px;
  display: grid;
  align-items: center;
  border: 1.5px dashed var(--line);
  border-radius: 8px;
  background: #fffdf8;
}

.material-reader {
  display: grid;
  gap: 18px;
  min-width: 0;
  padding: 18px;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background:
    linear-gradient(90deg, rgba(18, 18, 19, 0.035) 1px, transparent 1px) 0 0 / 24px 24px,
    #f6f0e7;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.86);
}

.reader-toolbar {
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  gap: 14px;
  padding: 14px;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: #fffdf8;
}

.reader-toolbar span,
.reader-section-head span,
.reader-note span {
  display: block;
  color: var(--coral);
  font-size: 11px;
  font-weight: 900;
  letter-spacing: 0;
  text-transform: uppercase;
}

.reader-toolbar strong {
  display: block;
  margin-top: 5px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(24px, 3vw, 38px);
  line-height: 0.95;
}

.reader-toolbar em,
.reader-section-head em {
  display: block;
  margin-top: 7px;
  color: var(--muted);
  font-size: 13px;
  font-style: normal;
  font-weight: 700;
}

.reader-section-toggle {
  display: grid;
  grid-template-columns: repeat(2, minmax(108px, 1fr));
  gap: 8px;
  min-width: min(280px, 100%);
}

.reader-section-toggle a,
.reader-page-thumb {
  color: var(--ink);
  text-decoration: none;
}

.reader-section-toggle a {
  display: grid;
  align-content: center;
  gap: 3px;
  min-height: 66px;
  padding: 9px 10px;
  border: 1.5px solid var(--ink);
  border-radius: 6px;
  background: #ffffff;
}

.reader-section-toggle b {
  font-size: 13px;
  text-transform: uppercase;
}

.reader-section-toggle small,
.reader-page-thumb small {
  color: var(--muted);
  font-size: 11px;
  font-weight: 800;
  text-transform: uppercase;
}

.reader-page-strip {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(68px, 1fr));
  gap: 8px;
  padding: 10px;
  border: 1.5px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.72);
}

.reader-page-thumb {
  display: grid;
  gap: 2px;
  min-height: 54px;
  padding: 8px;
  border: 1.5px solid rgba(18, 18, 19, 0.28);
  border-radius: 6px;
  background: #ffffff;
}

.reader-page-thumb:hover,
.reader-page-thumb:focus-visible,
.reader-section-toggle a:hover,
.reader-section-toggle a:focus-visible {
  outline: none;
  border-color: var(--ink);
  box-shadow: 0 0 0 3px rgba(36, 161, 72, 0.14);
}

.reader-page-thumb span {
  color: var(--coral);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 21px;
  font-weight: 900;
  line-height: 1;
}

.reader-note {
  display: grid;
  gap: 6px;
  padding: 12px 14px;
  border-left: 4px solid var(--green);
  background: #ffffff;
}

.reader-note strong {
  color: var(--ink);
  font-size: 14px;
  line-height: 1.55;
}

.reader-spread,
.reader-section {
  display: grid;
  gap: 22px;
  min-width: 0;
}

.reader-section {
  scroll-margin-top: 24px;
}

.reader-section-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 16px 18px;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: #fffdf8;
}

.reader-section-head strong {
  display: block;
  margin-top: 4px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(22px, 2.5vw, 34px);
  line-height: 1;
}

.reader-section-head b {
  flex: 0 0 auto;
  padding: 8px 10px;
  border: 1.5px solid var(--ink);
  border-radius: 999px;
  background: #ffffff;
  color: var(--ink);
  font-size: 12px;
  text-transform: uppercase;
}

.reader-page {
  margin: 0;
  padding: 16px;
  border: 1.5px solid rgba(18, 18, 19, 0.34);
  border-radius: 8px;
  background: #ffffff;
  box-shadow: 0 18px 34px rgba(18, 18, 19, 0.1);
}

.reader-page figcaption {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 0 0 12px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 900;
  text-transform: uppercase;
}

.reader-page figcaption em {
  font-style: normal;
}

.score-image-frame {
  background: #fff;
}

.score-image-frame img {
  display: block;
  width: min(100%, 980px);
  height: auto;
  margin: 0 auto;
  border: 1px solid rgba(18, 18, 19, 0.12);
  background: #fff;
  box-shadow: 0 12px 28px rgba(18, 18, 19, 0.08);
}

.course-map {
  display: grid;
  grid-template-columns: minmax(180px, 0.7fr) minmax(0, 1fr);
  gap: 16px;
  align-items: center;
  margin-bottom: 18px;
}

.staff-preview {
  position: relative;
  min-height: 180px;
  padding: 28px 16px;
  overflow: hidden;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: var(--paper-strong);
}

.staff-preview span {
  display: block;
  height: 2px;
  margin-top: 18px;
  background: rgba(18, 18, 19, 0.62);
}

.staff-preview b {
  position: absolute;
  left: var(--x);
  top: var(--y);
  width: 19px;
  height: 15px;
  border-radius: 50%;
  background: var(--blue);
  transform: rotate(-16deg);
}

.practice-steps {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 18px;
}

.practice-steps div,
.resource-workbench article {
  min-height: 128px;
  display: grid;
  align-content: start;
  gap: 8px;
  padding: 14px;
  border: 1.5px solid var(--line);
  border-radius: 8px;
  background: var(--paper-strong);
}

.practice-steps span,
.resource-workbench span,
.resource-note span,
.assessment-board span {
  color: var(--coral);
  font-size: 12px;
  font-weight: 900;
  text-transform: uppercase;
}

.practice-steps strong {
  color: var(--ink);
  font-size: 15px;
  line-height: 1.35;
}

.lesson-list {
  display: grid;
  grid-template-columns: minmax(110px, 0.28fr) minmax(0, 1fr);
  gap: 8px 14px;
  margin: 0;
}

.lesson-list dt,
.lesson-list dd {
  margin: 0;
  padding: 10px 0;
  border-top: 1.5px solid var(--line);
}

.lesson-list dt {
  color: var(--muted);
  font-size: 13px;
  font-weight: 900;
}

.lesson-list dd {
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.5;
}

.lesson-list.compact {
  margin-top: 14px;
}

.resource-workbench {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 14px;
}

.resource-workbench strong {
  color: var(--blue);
  font-family: var(--font-display);
  font-size: 46px;
  line-height: 1;
}

.resource-workbench em {
  color: var(--muted);
  font-size: 13px;
  font-style: normal;
  font-weight: 900;
}

.resource-note {
  display: grid;
  gap: 8px;
  padding: 18px;
  border: 1.5px dashed var(--line);
  border-radius: 8px;
  background:
    repeating-linear-gradient(135deg, rgba(18, 18, 19, 0.04) 0 8px, transparent 8px 16px),
    var(--paper-strong);
}

.resource-note strong {
  font-family: var(--font-display);
  font-size: 28px;
  line-height: 1.1;
}

.resource-note small {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.45;
}

.assessment-board {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 220px;
  gap: 16px;
  align-items: stretch;
}

.assessment-board > div:first-child {
  display: grid;
  align-content: center;
  padding: 20px;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: #fff9d7;
}

.assessment-board strong {
  display: block;
  margin: 8px 0;
  font-family: var(--font-display);
  font-size: 30px;
  line-height: 1.1;
}

.assessment-board p {
  margin: 0;
  font-size: 15px;
}

.blank-answer-sheet {
  display: grid;
  align-content: center;
  gap: 14px;
  padding: 20px;
  border: 1.5px solid var(--ink);
  border-radius: 8px;
  background: var(--paper-strong);
}

.blank-answer-sheet i {
  height: 22px;
  border: 1.5px solid var(--line);
  border-radius: 8px;
  background: linear-gradient(90deg, var(--pink) 0 22px, transparent 22px);
}

.footer-band {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 26px 24px;
  border-top: 2px solid var(--ink);
  background: var(--ink);
  color: #ffffff;
}

.footer-band strong {
  font-family: var(--font-display);
  font-size: 22px;
}

.footer-band p {
  max-width: 680px;
  margin: 0;
  color: rgba(255, 255, 255, 0.78);
  font-size: 14px;
}

@media (max-width: 1080px) {
  .hero,
  .product-row,
  .lesson-card {
    grid-template-columns: 1fr;
  }

  .showcase-object.cover-gallery-shell {
    width: 100vw;
    justify-self: start;
    left: auto;
    margin-left: calc(50% - 50vw);
    transform: none;
  }

  .cover-gallery-shell {
    min-height: 700px;
  }

  .hero {
    min-height: auto;
    gap: 22px;
  }

  .hero-product {
    min-height: 560px;
  }

  .theory-notebook {
    --notebook-shift: -50%;
    left: 50%;
    right: auto;
  }

  .level-board,
  .resource-label-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .lesson-section {
    grid-template-columns: 1fr;
    gap: 26px;
  }

  .lesson-cover,
  .lesson-main,
  .lesson-pane {
    grid-column: 1;
  }

  .lesson-cover {
    min-height: auto;
    border-right: 0;
    border-bottom: 2px solid var(--ink);
  }
}

@media (max-width: 720px) {
  .site-header,
  .hero,
  .product-row,
  .section {
    padding-left: 16px;
    padding-right: 16px;
  }

  .site-header,
  .catalog-head,
  .footer-band {
    align-items: flex-start;
    flex-direction: column;
  }

  .site-nav {
    justify-content: flex-start;
  }

  .hero {
    padding-top: 10px;
    padding-bottom: 64px;
  }

  .hero-product {
    min-height: 500px;
  }

  .theory-notebook {
    top: 54px;
    width: min(320px, calc(100vw - 44px));
  }

  .notebook-cover {
    min-height: 418px;
    padding: 24px 20px;
  }

  .rhythm-tiles {
    left: auto;
    right: 8px;
    bottom: 24px;
    grid-template-columns: repeat(2, 44px);
  }

  .rhythm-tiles span {
    width: 44px;
    height: 44px;
    font-size: 20px;
  }

  .filters,
  .level-board,
  .resource-label-grid,
  .lesson-course-strip,
  .course-map,
  .practice-steps,
  .resource-workbench,
  .assessment-board {
    grid-template-columns: 1fr;
  }

  .cover-gallery-shell {
    min-height: 700px;
  }

  .circular-gallery-card {
    width: min(340px, calc(100vw - 64px));
  }

  .lesson-tabs {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .lesson-tabs button:nth-child(2) {
    border-right: 0;
  }

  .lesson-tabs button:nth-child(-n + 2) {
    border-bottom: 1.5px solid var(--line);
  }

  .lesson-pane {
    padding: 18px;
  }

  .material-reader {
    padding: 12px;
  }

  .reader-toolbar,
  .reader-section-head {
    align-items: stretch;
    flex-direction: column;
  }

  .reader-section-toggle {
    grid-template-columns: 1fr;
  }

  .reader-page-strip {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 6px;
    padding: 8px;
  }

  .reader-page-thumb {
    min-height: 50px;
    padding: 7px;
  }

  .reader-page {
    padding: 10px;
  }

  .reader-page figcaption {
    flex-direction: column;
    gap: 4px;
  }

  .lesson-list {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 1ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 1ms !important;
  }
}