:root {
  --ink: #122027;
  --muted: #5d6b72;
  --paper: #fffaf1;
  --cream: #f8efe1;
  --sky: #d9f3ff;
  --mint: #dff7df;
  --coral: #ff6b6b;
  --blue: #246bfe;
  --green: #29a36a;
  --shadow: 0 24px 60px rgba(18, 32, 39, 0.16);
  font-family: "Segoe UI", Tahoma, Arial, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 8%, rgba(255, 208, 92, 0.45), transparent 28%),
    linear-gradient(135deg, #fff7e7 0%, #e7f8ff 45%, #f4f1ff 100%);
  min-height: 100vh;
  overflow-x: hidden;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 14px clamp(18px, 4vw, 54px);
  background: rgba(255, 252, 244, 0.82);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid rgba(18, 32, 39, 0.08);
}

.brand, .header-actions, nav, .language-picker {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand { font-weight: 900; font-size: 1.05rem; }
.brand-mark {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  color: white;
  background: linear-gradient(135deg, #ff6b6b, #246bfe);
  box-shadow: 0 12px 28px rgba(36, 107, 254, 0.25);
}

nav a {
  padding: 10px 12px;
  color: var(--muted);
  font-weight: 700;
  border-radius: 8px;
}
nav a:hover { background: rgba(36, 107, 254, 0.09); color: var(--ink); }

.member-pill, .lang-button {
  border: 1px solid rgba(18, 32, 39, 0.12);
  background: rgba(255, 255, 255, 0.7);
  border-radius: 8px;
  padding: 8px 10px;
  font-size: 0.82rem;
  font-weight: 800;
}
.member-pill { max-width: 180px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.member-pill.is-active { color: white; background: var(--green); }
.lang-button { cursor: pointer; color: var(--muted); }
.lang-button.is-active { background: var(--ink); color: white; }

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(340px, 0.85fr);
  align-items: center;
  min-height: calc(100vh - 80px);
  padding: clamp(38px, 6vw, 82px) clamp(18px, 5vw, 72px) 70px;
  gap: clamp(30px, 5vw, 70px);
}

#starfield {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0.5;
  pointer-events: none;
}

.hero-copy, .hero-stage { position: relative; z-index: 1; }
.kicker {
  display: inline-flex;
  align-items: center;
  padding: 8px 12px;
  border-radius: 8px;
  font-weight: 900;
  background: rgba(255, 255, 255, 0.68);
  color: #b13b3b;
}

h1 {
  max-width: 820px;
  margin: 18px 0;
  font-size: clamp(2.7rem, 6vw, 6.6rem);
  line-height: 0.96;
  letter-spacing: 0;
}

.hero p, .grade-hero p, .payment-hero p {
  color: var(--muted);
  font-size: clamp(1.05rem, 1.4vw, 1.35rem);
  line-height: 1.8;
  max-width: 720px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 18px;
  border: 0;
  border-radius: 8px;
  font-weight: 900;
  cursor: pointer;
}
.button.primary {
  color: white;
  background: linear-gradient(135deg, #ff6b6b, #246bfe);
  box-shadow: 0 18px 36px rgba(36, 107, 254, 0.23);
}
.button.ghost { background: white; color: var(--ink); }
.button.success { background: var(--green); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }

.hero-stage {
  min-height: 530px;
  perspective: 1000px;
  display: grid;
  place-items: center;
}

.book-3d {
  position: relative;
  width: min(78vw, 390px);
  height: 280px;
  transform-style: preserve-3d;
  animation: floatBook 5s ease-in-out infinite;
}

.book-cover, .book-page {
  position: absolute;
  inset: 0;
  border-radius: 14px;
  box-shadow: var(--shadow);
  transform-style: preserve-3d;
}
.book-cover {
  background: linear-gradient(135deg, #ffb84d, #ff6b6b 48%, #246bfe);
  transform: rotateX(58deg) rotateZ(-18deg);
}
.book-cover::before {
  content: "ABC";
  position: absolute;
  inset: 32px;
  display: grid;
  place-items: center;
  border: 3px dashed rgba(255,255,255,0.8);
  border-radius: 12px;
  color: white;
  font-size: 5rem;
  font-weight: 1000;
}
.book-page {
  background: repeating-linear-gradient(#fff, #fff 19px, #d5efff 20px);
  transform: rotateX(58deg) rotateZ(-18deg) translateZ(-24px) translateX(26px);
}

.letter-cube {
  position: absolute;
  width: 92px;
  height: 92px;
  transform-style: preserve-3d;
  animation: spinCube 9s linear infinite;
}
.letter-cube span,
.lesson-cube span {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  border-radius: 12px;
  color: white;
  font-size: 2.4rem;
  font-weight: 1000;
  background: var(--cube-color, #246bfe);
  box-shadow: inset 0 0 0 2px rgba(255,255,255,0.28);
}
.letter-cube span:nth-child(1), .lesson-cube span:nth-child(1) { transform: translateZ(46px); }
.letter-cube span:nth-child(2), .lesson-cube span:nth-child(2) { transform: rotateY(90deg) translateZ(46px); }
.letter-cube span:nth-child(3), .lesson-cube span:nth-child(3) { transform: rotateX(90deg) translateZ(46px); }
.letter-cube span:nth-child(4), .lesson-cube span:nth-child(4) { transform: rotateY(180deg) translateZ(46px); }
.letter-cube.one { --cube-color: #29b6f6; inset-inline-start: 6%; top: 12%; }
.letter-cube.two { --cube-color: #66bb6a; inset-inline-end: 4%; top: 18%; animation-duration: 11s; }
.letter-cube.three { --cube-color: #ec407a; inset-inline-start: 18%; bottom: 8%; animation-duration: 7s; }

.section {
  padding: 72px clamp(18px, 5vw, 72px);
}
.section h2, .payment-hero h1, .grade-hero h1 {
  margin: 0 0 18px;
  font-size: clamp(2rem, 4vw, 4rem);
  line-height: 1.06;
}
.section-intro { color: var(--muted); max-width: 760px; line-height: 1.8; }

.grade-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-top: 28px;
}
.grade-card {
  position: relative;
  min-height: 285px;
  padding: 24px;
  border-radius: 8px;
  background: rgba(255,255,255,0.78);
  border: 1px solid rgba(18,32,39,0.08);
  box-shadow: 0 16px 38px rgba(18, 32, 39, 0.08);
  overflow: hidden;
}
.grade-card::after {
  content: "";
  position: absolute;
  width: 150px;
  height: 150px;
  inset-inline-end: -40px;
  bottom: -50px;
  border-radius: 50%;
  background: color-mix(in srgb, var(--accent), transparent 45%);
}
.grade-card p { color: var(--muted); line-height: 1.7; }
.grade-card h3 { font-size: 1.55rem; margin: 12px 0; }
.eg-card-image {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-radius: 8px;
  margin-bottom: 16px;
  border: 1px solid rgba(18,32,39,0.08);
}
.eg-media-block {
  display: grid;
  gap: 12px;
  margin: 18px 0;
}
.eg-media-block img,
.eg-media-block video {
  display: block;
  width: 100%;
  max-height: 360px;
  object-fit: cover;
  border-radius: 8px;
  border: 1px solid rgba(18,32,39,0.08);
  box-shadow: 0 12px 28px rgba(18, 32, 39, 0.08);
}
.eg-media-block audio {
  display: block;
  width: 100%;
}
.grade-orbit {
  width: 68px;
  height: 68px;
  display: grid;
  place-items: center;
  border-radius: 18px;
  color: white;
  font-size: 1.8rem;
  font-weight: 1000;
  background: var(--accent);
  transform: rotate(-8deg);
}
.small-link {
  position: absolute;
  bottom: 22px;
  display: inline-flex;
  font-weight: 1000;
  color: var(--blue);
}

.feature-band {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.feature {
  padding: 22px;
  border-radius: 8px;
  background: rgba(18, 32, 39, 0.9);
  color: white;
  min-height: 160px;
}
.feature p { color: rgba(255,255,255,0.72); line-height: 1.7; }

.grade-hero, .payment-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  align-items: center;
  gap: 34px;
  padding: 70px clamp(18px, 5vw, 72px);
  min-height: 520px;
}
.grade-hero { background: linear-gradient(135deg, color-mix(in srgb, var(--accent), white 72%), rgba(255,255,255,0.4)); }
.payment-hero { background: linear-gradient(135deg, #e6f7ff, #fff2dc); }

.lesson-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 360px;
  align-items: center;
  gap: 34px;
  min-height: 560px;
  padding: 70px clamp(18px, 5vw, 72px);
  background:
    radial-gradient(circle at 78% 34%, rgba(255, 184, 77, 0.42), transparent 22%),
    linear-gradient(135deg, #fff3d6, #dff7ff 55%, #f4f1ff);
}

.lesson-hero h1 {
  font-size: clamp(3.2rem, 8vw, 7rem);
}

.planet-scene {
  position: relative;
  width: min(74vw, 340px);
  aspect-ratio: 1;
  display: grid;
  place-items: center;
  margin: auto;
  transform-style: preserve-3d;
  animation: floatBook 5.4s ease-in-out infinite;
}

.planet-core {
  width: 190px;
  height: 190px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: white;
  font-size: 3rem;
  font-weight: 1000;
  background: linear-gradient(135deg, #ff6b6b, #246bfe);
  box-shadow: 0 28px 70px rgba(36,107,254,0.28);
}

.planet-scene span {
  position: absolute;
  width: 72px;
  height: 72px;
  display: grid;
  place-items: center;
  border-radius: 18px;
  color: white;
  font-size: 2rem;
  font-weight: 1000;
  background: #122027;
  box-shadow: var(--shadow);
  animation: spinCube 9s linear infinite;
}

.planet-scene span:nth-child(2) { top: 8%; inset-inline-start: 18%; background: #ff6b6b; }
.planet-scene span:nth-child(3) { top: 18%; inset-inline-end: 4%; background: #29b6f6; animation-duration: 7s; }
.planet-scene span:nth-child(4) { bottom: 10%; inset-inline-start: 4%; background: #66bb6a; animation-duration: 8s; }
.planet-scene span:nth-child(5) { bottom: 6%; inset-inline-end: 20%; background: #ffa726; animation-duration: 10s; }

.progress-shell {
  width: min(520px, 100%);
  height: 16px;
  border-radius: 999px;
  background: rgba(18,32,39,0.1);
  overflow: hidden;
  margin-top: 24px;
}
.progress-shell span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: var(--accent);
}
.mini-copy { font-size: 0.95rem !important; }

.lesson-cube {
  position: relative;
  width: 150px;
  height: 150px;
  margin: auto;
  transform-style: preserve-3d;
  animation: spinCube 7s linear infinite;
  --cube-color: var(--accent);
}
.lesson-cube span { font-size: 4rem; border-radius: 18px; }
.lesson-cube span:nth-child(1) { transform: translateZ(75px); }
.lesson-cube span:nth-child(2) { transform: rotateY(90deg) translateZ(75px); }
.lesson-cube span:nth-child(3) { transform: rotateX(90deg) translateZ(75px); }
.lesson-cube span:nth-child(4) { transform: rotateY(180deg) translateZ(75px); }

.split-band {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 360px;
  gap: 22px;
  padding: 54px clamp(18px, 5vw, 72px);
}
.timeline {
  display: grid;
  gap: 12px;
}
.timeline-item, .practice-panel, .price-card {
  border: 1px solid rgba(18,32,39,0.09);
  background: rgba(255,255,255,0.82);
  border-radius: 8px;
  box-shadow: 0 14px 34px rgba(18,32,39,0.08);
}
.timeline-item {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 18px;
}
.timeline-item span { color: var(--muted); }
.practice-panel { padding: 22px; }
.flash-card {
  min-height: 180px;
  display: grid;
  place-items: center;
  margin: 18px 0;
  border-radius: 8px;
  background: linear-gradient(135deg, #122027, #246bfe);
  color: white;
  text-align: center;
}
.flash-card strong { display: block; font-size: 2.4rem; }
.flash-card span { color: rgba(255,255,255,0.72); }

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 380px));
  gap: 20px;
  justify-content: center;
  padding: 40px clamp(18px, 5vw, 72px) 80px;
}
.price-card { padding: 26px; }
.price-card.featured { border: 2px solid #246bfe; transform: translateY(-8px); }
.price-card h2 { font-size: 3rem; margin: 8px 0; }
.price-card li { margin: 12px 0; }

.auth-section {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 420px));
  justify-content: center;
  gap: 20px;
  padding: 54px clamp(18px, 5vw, 72px) 80px;
}

.auth-card {
  padding: 26px;
  border-radius: 8px;
  border: 1px solid rgba(18,32,39,0.09);
  background: rgba(255,255,255,0.86);
  box-shadow: 0 16px 38px rgba(18,32,39,0.08);
}

.auth-card form {
  display: grid;
  gap: 12px;
}

.auth-card input[type="text"],
.auth-card input[type="password"],
.auth-card input[type="email"] {
  width: 100%;
  min-height: 44px;
  padding: 10px 12px;
  border: 1px solid rgba(18,32,39,0.18);
  border-radius: 8px;
}

.auth-card input[type="submit"] {
  min-height: 48px;
  border: 0;
  border-radius: 8px;
  color: white;
  font-weight: 900;
  background: linear-gradient(135deg, #ff6b6b, #246bfe);
  cursor: pointer;
}

.auth-card label {
  display: grid;
  gap: 7px;
  color: var(--muted);
  font-weight: 800;
}

.auth-message {
  padding: 12px;
  border-radius: 8px;
  color: #8a1f1f;
  background: #ffe8e8;
  border: 1px solid rgba(255, 107, 107, 0.35);
}

.materials-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.material-card {
  min-height: 245px;
  padding: 24px;
  border-radius: 8px;
  border: 1px solid rgba(18,32,39,0.09);
  background:
    linear-gradient(145deg, rgba(255,255,255,0.92), rgba(235,248,255,0.82));
  box-shadow: 0 16px 38px rgba(18, 32, 39, 0.08);
  cursor: pointer;
  transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.material-card:hover,
.material-card.is-active {
  transform: translateY(-4px);
  border-color: rgba(36, 107, 254, 0.42);
  box-shadow: 0 22px 48px rgba(36, 107, 254, 0.14);
}

.material-icon {
  width: 58px;
  height: 58px;
  display: grid;
  place-items: center;
  border-radius: 16px;
  color: white;
  font-size: 1.5rem;
  font-weight: 1000;
  background: linear-gradient(135deg, #29b6f6, #66bb6a);
}

.material-card p {
  color: #246bfe;
  font-weight: 900;
}

.material-card h3 {
  margin: 8px 0;
  font-size: 1.45rem;
}

.material-card span {
  display: block;
  color: var(--muted);
  line-height: 1.7;
}

.material-detail-panel {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  gap: 22px;
  margin-top: 8px;
  padding: 28px;
  border-radius: 8px;
  color: white;
  background: linear-gradient(135deg, #122027, #246bfe);
  box-shadow: 0 24px 60px rgba(18, 32, 39, 0.16);
}

.material-detail-panel h2 {
  margin: 14px 0 10px;
  font-size: clamp(2rem, 4vw, 4rem);
}

.material-detail-panel p {
  color: rgba(255,255,255,0.78);
  line-height: 1.8;
}

.material-detail-panel aside {
  padding: 20px;
  border-radius: 8px;
  background: rgba(255,255,255,0.12);
}

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

.material-action-grid button {
  min-height: 72px;
  display: grid;
  place-items: center;
  padding: 10px;
  border-radius: 8px;
  border: 0;
  text-align: center;
  color: #122027;
  font-weight: 900;
  background: linear-gradient(135deg, #fff7e7, #d9f3ff);
  cursor: pointer;
}

.material-action-grid button:hover,
.material-action-grid button.is-active {
  background: linear-gradient(135deg, #ffd36a, #ffffff);
  box-shadow: 0 12px 24px rgba(255, 211, 106, 0.18);
}

.material-action-result {
  margin-top: 16px;
  padding: 16px;
  border-radius: 8px;
  color: rgba(255,255,255,0.84);
  background: rgba(255,255,255,0.1);
}

.material-action-result strong,
.material-action-result span {
  display: block;
}

.material-action-result strong {
  color: #ffd36a;
  margin-bottom: 6px;
}

.lesson-section-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-top: 24px;
}

.lesson-section-card {
  min-height: 230px;
  padding: 24px;
  border-radius: 8px;
  border: 1px solid rgba(18,32,39,0.09);
  background: rgba(255,255,255,0.86);
  box-shadow: 0 16px 38px rgba(18, 32, 39, 0.08);
  cursor: pointer;
  transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}

.lesson-section-card:hover,
.lesson-section-card.is-active {
  transform: translateY(-4px);
  border-color: rgba(36, 107, 254, 0.42);
  box-shadow: 0 22px 48px rgba(36, 107, 254, 0.14);
}

.lesson-section-card p {
  display: inline-flex;
  padding: 7px 10px;
  margin: 0;
  border-radius: 8px;
  color: white;
  font-weight: 900;
  background: #246bfe;
}

.lesson-section-card h3 {
  margin: 16px 0 10px;
  font-size: 1.35rem;
}

.lesson-section-card span {
  color: var(--muted);
  line-height: 1.7;
}

.alphabet-grid {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 14px;
  margin-top: 24px;
}

.alphabet-card {
  min-height: 168px;
  display: grid;
  gap: 8px;
  align-content: center;
  padding: 18px;
  border-radius: 8px;
  text-align: center;
  background:
    linear-gradient(145deg, rgba(255,255,255,0.94), rgba(255,246,225,0.84));
  border: 1px solid rgba(18,32,39,0.08);
  box-shadow: 0 12px 28px rgba(18,32,39,0.07);
  cursor: pointer;
  transition: transform 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
}

.alphabet-card:hover,
.alphabet-card.is-active {
  transform: translateY(-4px);
  border-color: rgba(255, 107, 107, 0.46);
  box-shadow: 0 18px 36px rgba(255, 107, 107, 0.14);
}

.alphabet-card strong {
  font-size: clamp(2.4rem, 5vw, 4rem);
  line-height: 1;
  color: #ff6b6b;
}

.alphabet-card span {
  font-size: 1.1rem;
  font-weight: 900;
}

.alphabet-card small {
  color: var(--muted);
  line-height: 1.4;
}

.resource-links {
  display: grid;
  gap: 10px;
}

.card-practice-panel,
.day-practice-panel {
  margin-top: 18px;
  padding: 20px;
  border-radius: 8px;
  border: 1px solid rgba(18,32,39,0.08);
  background: rgba(255,255,255,0.86);
  box-shadow: 0 14px 34px rgba(18,32,39,0.08);
}

.card-practice-panel h3 {
  margin: 0 0 8px;
  font-size: 1.35rem;
}

.card-practice-panel p,
.day-practice-panel {
  color: var(--muted);
  line-height: 1.7;
}

.timeline-item[data-day-activity] {
  cursor: pointer;
  transition: transform 180ms ease, border-color 180ms ease;
}

.timeline-item[data-day-activity]:hover,
.timeline-item[data-day-activity].is-active {
  transform: translateX(4px);
  border-color: rgba(36,107,254,0.35);
}

.lesson-download-band {
  background: linear-gradient(135deg, rgba(231,248,255,0.88), rgba(255,247,231,0.88));
}

.active-material-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 0.55fr);
  gap: 18px;
  margin-top: 24px;
  padding: 24px;
  border-radius: 8px;
  background: rgba(18, 32, 39, 0.92);
  color: white;
  box-shadow: 0 22px 54px rgba(18, 32, 39, 0.18);
}

.active-material-panel .kicker {
  color: #ffd36a;
  background: rgba(255,255,255,0.12);
}

.active-material-copy h2 {
  margin: 16px 0 10px;
  font-size: clamp(1.8rem, 3vw, 3rem);
}

.active-material-copy p {
  color: rgba(255,255,255,0.76);
  line-height: 1.8;
}

.active-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
}

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

.active-preview span {
  min-height: 84px;
  display: grid;
  place-items: center;
  padding: 12px;
  border-radius: 8px;
  text-align: center;
  color: #122027;
  font-weight: 1000;
  background: linear-gradient(135deg, #fff7e7, #d9f3ff);
}

footer {
  padding: 28px clamp(18px, 5vw, 72px);
  color: var(--muted);
  border-top: 1px solid rgba(18,32,39,0.08);
  background: rgba(255,255,255,0.45);
}

@keyframes floatBook {
  0%, 100% { transform: translateY(0) rotateZ(0deg); }
  50% { transform: translateY(-20px) rotateZ(2deg); }
}

@keyframes spinCube {
  from { transform: rotateX(-18deg) rotateY(0deg); }
  to { transform: rotateX(-18deg) rotateY(360deg); }
}

@media (max-width: 920px) {
  .site-header { flex-wrap: wrap; }
  nav { order: 3; width: 100%; overflow-x: auto; }
  .hero, .grade-hero, .payment-hero, .lesson-hero, .split-band {
    grid-template-columns: 1fr;
  }
  .hero { min-height: auto; }
  .hero-stage { min-height: 390px; }
  .grade-grid, .feature-band { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .materials-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .auth-section { grid-template-columns: 1fr; }
  .material-detail-panel { grid-template-columns: 1fr; }
  .material-action-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .lesson-section-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .alphabet-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .active-material-panel { grid-template-columns: 1fr; }
  .pricing-grid { grid-template-columns: minmax(0, 1fr); }
  .price-card.featured { transform: none; }
}

@media (max-width: 620px) {
  .header-actions { width: 100%; justify-content: space-between; }
  .member-pill { max-width: 44vw; }
  h1 { font-size: clamp(2.25rem, 14vw, 4rem); }
  .grade-grid, .feature-band, .materials-grid, .lesson-section-grid { grid-template-columns: 1fr; }
  .alphabet-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .book-3d { width: 280px; height: 210px; }
  .letter-cube { width: 70px; height: 70px; }
  .letter-cube span { font-size: 1.8rem; }
  .timeline-item { flex-direction: column; }
}