:root {
  --navy: #073873;
  --blue: #0d4a8f;
  --orange: #fd5f0d;
  --orange-dark: #d94e08;
  --ink: #172033;
  --muted: #657085;
  --line: #dce4ef;
  --surface: #ffffff;
  --soft: #f4f7fb;
  --cream: #fff7e7;
  --shadow: 0 20px 50px rgba(7, 56, 115, 0.14);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-bvp), "Be Vietnam Pro", Arial, sans-serif;
  background: var(--surface);
}

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

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 76px;
  padding: 12px clamp(18px, 5vw, 72px);
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid rgba(220, 228, 239, 0.84);
  backdrop-filter: blur(16px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0;
  color: var(--navy);
  font-size: 1.05rem;
  font-weight: 800;
}

.brand img {
  height: 52px;
  width: auto;
  object-fit: contain;
  transition: transform 220ms ease, box-shadow 220ms ease;
}

.brand:hover img {
  box-shadow: 0 10px 24px rgba(7, 56, 115, 0.14);
  transform: translateY(-1px) scale(1.04);
}

.main-nav {
  display: flex;
  gap: clamp(14px, 3vw, 32px);
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 600;
}

.main-nav a:hover,
.site-footer a:hover {
  color: var(--orange);
}

.main-nav a {
  position: relative;
  transition: color 180ms ease;
}

.main-nav a::after {
  position: absolute;
  right: 0;
  bottom: -10px;
  left: 0;
  height: 2px;
  background: var(--orange);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform 220ms ease;
  content: "";
}

.main-nav a:hover::after {
  transform: scaleX(1);
}

.header-cta,
.primary-button,
.secondary-button {
  position: relative;
  overflow: hidden;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  border-radius: 8px;
  font-family: inherit;
  font-size: 1rem;
  font-weight: 800;
  line-height: 1;
  transition: transform 200ms ease, box-shadow 200ms ease, border-color 200ms ease,
    background-color 200ms ease, color 200ms ease;
}

.header-cta::before,
.primary-button::before {
  position: absolute;
  top: 0;
  bottom: 0;
  left: -70%;
  width: 48%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.38), transparent);
  transform: skewX(-18deg);
  transition: left 520ms ease;
  content: "";
}

.header-cta:hover,
.primary-button:hover,
.secondary-button:hover {
  transform: translateY(-2px);
}

.header-cta:hover::before,
.primary-button:hover::before {
  left: 118%;
}

/* Ánh sáng lướt tự động 1 lượt khi nút vào viewport (JS gắn .shine-once).
   Dùng keyframe left thay transition để chạy độc lập với hover. */
@keyframes shine-sweep {
  from {
    left: -70%;
  }
  to {
    left: 118%;
  }
}

.header-cta.shine-once::before,
.primary-button.shine-once::before {
  animation: shine-sweep 720ms ease forwards;
}

@media (prefers-reduced-motion: reduce) {
  .header-cta.shine-once::before,
  .primary-button.shine-once::before {
    animation: none;
  }
}

.header-cta,
.primary-button {
  color: #ffffff;
  background: var(--orange);
  box-shadow: 0 14px 28px rgba(253, 95, 13, 0.26);
}

.header-cta {
  padding: 0 18px;
  white-space: nowrap;
}

/* Nhóm nút bên phải header + nút Đăng nhập/Đăng ký */
.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.header-login {
  display: inline-flex;
  align-items: center;
  min-height: 46px;
  padding: 0 16px;
  border-radius: 8px;
  border: 1.5px solid rgba(7, 56, 115, 0.16);
  color: var(--navy);
  font-weight: 700;
  font-size: 0.9rem;
  text-decoration: none;
  white-space: nowrap;
  transition: border-color 200ms ease, color 200ms ease, background-color 200ms ease;
}

.header-login:hover {
  border-color: var(--blue, #0d4a8f);
  background: rgba(7, 56, 115, 0.04);
}

/* Chip chào mừng khi ĐÃ đăng nhập (thay chỗ nút "Đăng nhập/Đăng ký").
   Cùng gia đình với .header-login: viền mảnh navy, bo 8px, cao 46px.
   Điểm nhấn = avatar tròn gradient navy→cam mang chữ cái đầu tên. */
.header-welcome {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 46px;
  padding: 4px 14px 4px 5px;
  border-radius: 999px;
  border: 1.5px solid rgba(7, 56, 115, 0.16);
  background: #ffffff;
  text-decoration: none;
  white-space: nowrap;
  transition: border-color 200ms ease, background-color 200ms ease,
    transform 200ms ease, box-shadow 200ms ease;
}

.header-welcome:hover {
  border-color: rgba(253, 95, 13, 0.5);
  background: rgba(253, 95, 13, 0.05);
  transform: translateY(-1px);
  box-shadow: 0 10px 24px rgba(7, 56, 115, 0.1);
}

.header-avatar {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--navy) 0%, var(--orange) 130%);
  color: #ffffff;
  font-size: 1rem;
  font-weight: 800;
  line-height: 1;
  box-shadow: 0 4px 12px rgba(7, 56, 115, 0.22);
}

.header-welcome-text {
  display: flex;
  flex-direction: column;
  gap: 1px;
  line-height: 1.1;
}

.header-welcome-hi {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--muted);
}

.header-welcome-name {
  font-size: 0.92rem;
  font-weight: 800;
  color: var(--navy);
}

.primary-button {
  border: 0;
  padding: 0 22px;
  cursor: pointer;
}

.secondary-button {
  padding: 0 22px;
  color: var(--navy);
  border: 1px solid var(--line);
  background: #ffffff;
}

.primary-button:hover,
.header-cta:hover {
  background: var(--orange-dark);
  box-shadow: 0 18px 34px rgba(253, 95, 13, 0.32);
}

.secondary-button:hover {
  border-color: var(--blue);
  color: var(--blue);
  box-shadow: 0 14px 28px rgba(7, 56, 115, 0.11);
}

.section-band {
  position: relative;
  overflow: hidden;
  background:
    radial-gradient(circle at 10% 20%, rgba(253, 95, 13, 0.16), transparent 32%),
    radial-gradient(circle at 95% 15%, rgba(13, 74, 143, 0.13), transparent 34%),
    var(--cream);
}

.hero {
  display: grid;
  grid-template-columns: minmax(320px, 0.95fr) minmax(0, 1.05fr);
  align-items: center;
  gap: clamp(28px, 6vw, 76px);
  min-height: calc(100vh - 76px);
  padding: clamp(46px, 7vw, 88px) clamp(18px, 5vw, 72px);
  color: var(--ink);
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 720px;
}

.eyebrow {
  display: inline-block;
  margin: 0 0 16px;
  padding: 7px 14px;
  border-radius: 999px;
  color: var(--orange);
  background: rgba(253, 95, 13, 0.1);
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.hero h1,
.section h2 {
  margin: 0;
  letter-spacing: 0;
}

.hero h1 {
  color: var(--navy);
  font-size: clamp(3.1rem, 7vw, 6.8rem);
  line-height: 0.95;
}

.hero-copy {
  max-width: 650px;
  margin: 24px 0 0;
  color: var(--muted);
  font-size: clamp(1rem, 1.7vw, 1.22rem);
  line-height: 1.8;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 34px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin-top: 42px;
}

.hero-stats > * {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 96px;
  padding: 18px;
  border: 1px solid rgba(7, 56, 115, 0.1);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.72);
  transition: transform 220ms ease, box-shadow 220ms ease, background-color 220ms ease;
}

/* Cả 3 ô stat cùng khuôn .hero-stat-link (link hoặc div), là grid-item trực tiếp. */
.hero-stat-link {
  text-align: left;
  font: inherit;
  color: inherit;
  cursor: pointer;
  text-decoration: none;
}

.hero-stats > *:hover {
  background: #ffffff;
  box-shadow: 0 12px 28px rgba(7, 56, 115, 0.1);
  transform: translateY(-4px);
}

.hero-stats strong,
.hero-stats span {
  display: block;
}

.hero-stats strong {
  color: var(--navy);
  font-size: 1rem;
}

.hero-stats span {
  margin-top: 8px;
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.45;
}

.teacher-showcase {
  position: relative;
  display: grid;
  min-height: min(620px, 78vh);
  align-items: center;
  isolation: isolate;
  animation: revealScale 760ms cubic-bezier(0.2, 0.82, 0.2, 1) both;
}

.teacher-showcase::before,
.teacher-showcase::after {
  position: absolute;
  z-index: -1;
  display: block;
  border-radius: 999px;
  content: "";
}

.teacher-showcase::before {
  width: min(420px, 78vw);
  height: min(420px, 78vw);
  left: 5%;
  top: 12%;
  background: var(--orange);
  opacity: 0.16;
  animation: slowPulse 6s ease-in-out infinite;
}

.teacher-showcase::after {
  width: min(330px, 62vw);
  height: min(330px, 62vw);
  right: 6%;
  bottom: 4%;
  background: var(--navy);
  opacity: 0.12;
  animation: slowPulse 7s ease-in-out infinite reverse;
}

.hero-teacher {
  position: relative;
  width: min(360px, 70vw);
  padding: 8px;
  border-radius: 999px;
  background: #ffffff;
  box-shadow: var(--shadow);
  transition: box-shadow 280ms ease;
}

.hero-teacher img {
  aspect-ratio: 1;
  width: 100%;
  border-radius: 999px;
  object-fit: cover;
  transition: transform 540ms ease;
}

.hero-teacher:hover {
  box-shadow: 0 28px 62px rgba(7, 56, 115, 0.18);
}

.hero-teacher:hover img {
  transform: scale(1.035);
}

.hero-teacher div {
  position: absolute;
  z-index: 2;
  display: grid;
  gap: 4px;
  min-width: 150px;
  padding: 12px 16px;
  border-radius: 8px;
  color: #ffffff;
  background: var(--navy);
  box-shadow: 0 14px 28px rgba(7, 56, 115, 0.2);
}

.hero-teacher span {
  font-weight: 800;
}

.hero-teacher strong {
  color: var(--orange);
  font-size: 1rem;
  font-weight: 800;
}

.hero-teacher-main {
  justify-self: start;
  animation: floatTeacher 5.8s ease-in-out infinite;
}

.hero-teacher-main div {
  left: 22px;
  bottom: -14px;
}

.hero-teacher-secondary {
  position: absolute;
  right: 0;
  bottom: 14px;
  width: min(250px, 48vw);
  animation: floatTeacher 6.8s ease-in-out 0.4s infinite;
}

.hero-teacher-secondary div {
  right: 6px;
  bottom: -10px;
  background: var(--navy);
}

.section {
  padding: clamp(48px, 6vw, 68px) clamp(18px, 5vw, 72px);
}

/* Nền xen kẽ để khoảng trắng giữa các section thành nhịp phân tách rõ ràng
   (thay vì trắng liền nhau nhìn trống trải). kem → xám → trắng → xám → trắng… */
.roadmap-section,
.mock-section {
  background: var(--soft);
}

.section-heading {
  max-width: 760px;
  margin-bottom: 34px;
}

.section h2 {
  color: var(--navy);
  font-size: clamp(2rem, 4vw, 3.4rem);
  line-height: 1.1;
}

.section-copy,
.contact-copy p {
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.8;
}

.teachers-section {
  background: #ffffff;
}

.teacher-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.teacher-card {
  display: grid;
  grid-template-columns: minmax(180px, 0.68fr) minmax(0, 1fr);
  align-items: stretch;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: 0 14px 34px rgba(7, 56, 115, 0.09);
  transition: transform 240ms ease, box-shadow 240ms ease, border-color 240ms ease;
}

.teacher-card:hover {
  border-color: rgba(253, 95, 13, 0.34);
  box-shadow: 0 24px 52px rgba(7, 56, 115, 0.14);
  transform: translateY(-6px);
}

.teacher-card img {
  width: 100%;
  height: 100%;
  min-height: 300px;
  object-fit: cover;
  transition: transform 540ms ease;
}

.teacher-card:hover img {
  transform: scale(1.04);
}

.teacher-card-body {
  display: grid;
  align-content: center;
  gap: 10px;
  padding: clamp(20px, 4vw, 32px);
}

.teacher-card-body p {
  margin: 0;
  color: var(--orange);
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
}

.teacher-card-body h3 {
  margin: 0;
  color: var(--navy);
  font-size: clamp(1.5rem, 3vw, 2.3rem);
}

.ielts-score {
  width: fit-content;
  padding: 6px 10px;
  border-radius: 8px;
  color: #ffffff;
  font-size: 0.95rem;
  font-style: normal;
  font-weight: 800;
  background: var(--orange);
  box-shadow: 0 10px 22px rgba(253, 95, 13, 0.2);
  transition: transform 200ms ease, box-shadow 200ms ease;
}

.teacher-card:hover .ielts-score {
  box-shadow: 0 14px 30px rgba(253, 95, 13, 0.32);
  transform: translateY(-1px);
}

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

.path-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.path-card {
  min-height: 240px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: 0 10px 24px rgba(7, 56, 115, 0.07);
  transition: transform 240ms ease, box-shadow 240ms ease, border-color 240ms ease;
}

.path-card:hover {
  border-color: rgba(13, 74, 143, 0.24);
  box-shadow: 0 18px 38px rgba(7, 56, 115, 0.12);
  transform: translateY(-5px);
}

.path-card span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  color: #ffffff;
  background: var(--navy);
  font-weight: 800;
  transition: background-color 220ms ease, transform 220ms ease;
}

.path-card:hover span {
  background: var(--orange);
  transform: scale(1.06);
}

.path-card h3,
.feature-item h3 {
  margin: 22px 0 10px;
  color: var(--navy);
  font-size: 1.05rem;
}

.path-card p,
.feature-item p {
  margin: 0;
  color: var(--muted);
  line-height: 1.65;
}

.split {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(320px, 1fr);
  gap: clamp(28px, 6vw, 76px);
  align-items: start;
  background: var(--soft);
}

.feature-list {
  display: grid;
  gap: 14px;
}

.feature-item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 18px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
  transition: transform 220ms ease, box-shadow 220ms ease, border-color 220ms ease;
}

.feature-item:hover {
  border-color: rgba(253, 95, 13, 0.3);
  box-shadow: 0 16px 34px rgba(7, 56, 115, 0.1);
  transform: translateX(4px);
}

.feature-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 8px;
  color: #ffffff;
  background: var(--orange);
  font-weight: 800;
  transition: transform 220ms ease;
}

.feature-item:hover .feature-icon {
  transform: rotate(-4deg) scale(1.06);
}

.feature-item h3 {
  margin-top: 0;
}

.contact-section {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(320px, 520px);
  gap: clamp(28px, 6vw, 72px);
  align-items: start;
}

.contact-copy {
  max-width: 660px;
}

.contact-note {
  display: grid;
  gap: 8px;
  margin-top: 28px;
  padding: 18px;
  border-left: 4px solid var(--orange);
  background: var(--soft);
  color: var(--muted);
  line-height: 1.6;
}

.contact-note strong {
  color: var(--navy);
}

.lead-form {
  display: grid;
  gap: 16px;
  padding: clamp(22px, 4vw, 32px);
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
  box-shadow: var(--shadow);
  transition: transform 240ms ease, box-shadow 240ms ease;
}

.lead-form:focus-within {
  box-shadow: 0 28px 58px rgba(7, 56, 115, 0.16);
  transform: translateY(-2px);
}

.lead-form label {
  display: grid;
  gap: 8px;
  color: var(--navy);
  font-size: 0.92rem;
  font-weight: 800;
}

.lead-form input,
.lead-form select,
.lead-form textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 13px 14px;
  color: var(--ink);
  font: inherit;
  font-weight: 500;
  background: #ffffff;
  transition: border-color 180ms ease, box-shadow 180ms ease, background-color 180ms ease;
}

.lead-form textarea {
  resize: vertical;
}

.lead-form input:focus,
.lead-form select:focus,
.lead-form textarea:focus {
  border-color: var(--blue);
  outline: 3px solid rgba(13, 74, 143, 0.13);
  box-shadow: 0 10px 24px rgba(13, 74, 143, 0.08);
}

.form-button {
  width: 100%;
  margin-top: 4px;
}

.form-status {
  min-height: 22px;
  margin: 0;
  color: var(--blue);
  font-size: 0.92rem;
  font-weight: 700;
  line-height: 1.5;
}

.form-status.is-visible {
  animation: fadeUp 320ms ease both;
}

.form-status--ok {
  padding: 12px 14px;
  border-radius: 12px;
  background: #e8f6ee;
  border: 1px solid #b6e3c6;
  color: #1b7a43;
}

.form-status--error {
  padding: 12px 14px;
  border-radius: 12px;
  background: #fdecea;
  border: 1px solid #f5c2bd;
  color: #c0392b;
}

.site-footer {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
  padding: 40px clamp(18px, 5vw, 72px);
  color: rgba(255, 255, 255, 0.76);
  background: var(--navy);
}

.footer-brand {
  display: grid;
  gap: 8px;
  max-width: 360px;
}

.site-footer strong {
  color: #ffffff;
  font-size: 1.15rem;
}

.footer-address {
  color: rgba(255, 255, 255, 0.7);
  font-size: 0.9rem;
  line-height: 1.5;
}

/* Khối mạng xã hội */
.footer-social {
  display: grid;
  gap: 12px;
}

.footer-social-label {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.6);
}

.footer-social-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.footer-social-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 15px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: rgba(255, 255, 255, 0.06);
  color: #ffffff;
  font-weight: 600;
  font-size: 0.9rem;
  transition: background-color 200ms ease, border-color 200ms ease, transform 200ms ease;
}

.footer-social-link:hover {
  background: rgba(255, 255, 255, 0.14);
  border-color: var(--orange);
  color: var(--orange);
  transform: translateY(-2px);
}

.footer-social-link svg {
  flex-shrink: 0;
}

/* Nút đăng ký ở footer */
.footer-cta {
  display: inline-flex;
  align-items: center;
  align-self: center;
  padding: 12px 22px;
  border-radius: 8px;
  background: var(--orange);
  color: #ffffff;
  font-weight: 800;
  transition: background-color 200ms ease, transform 200ms ease;
}

.footer-cta:hover {
  background: var(--orange-dark);
  transform: translateY(-2px);
}

.hero-content .eyebrow,
.hero-content h1,
.hero-copy,
.hero-actions,
.hero-stats {
  animation: fadeUp 720ms cubic-bezier(0.2, 0.82, 0.2, 1) both;
}

.hero-content .eyebrow {
  animation-delay: 80ms;
}

.hero-content h1 {
  animation-delay: 160ms;
}

.hero-copy {
  animation-delay: 240ms;
}

.hero-actions {
  animation-delay: 320ms;
}

.hero-stats {
  animation-delay: 400ms;
}

.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 680ms cubic-bezier(0.2, 0.82, 0.2, 1),
    transform 680ms cubic-bezier(0.2, 0.82, 0.2, 1);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.path-grid .reveal:nth-child(2),
.teacher-grid .reveal:nth-child(2),
.feature-list .reveal:nth-child(2) {
  transition-delay: 90ms;
}

.path-grid .reveal:nth-child(3),
.feature-list .reveal:nth-child(3) {
  transition-delay: 180ms;
}

.path-grid .reveal:nth-child(4) {
  transition-delay: 270ms;
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes revealScale {
  from {
    opacity: 0;
    transform: translateY(18px) scale(0.96);
  }

  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@keyframes floatTeacher {
  0%,
  100% {
    transform: translateY(0);
  }

  50% {
    transform: translateY(-10px);
  }
}

@keyframes slowPulse {
  0%,
  100% {
    transform: scale(1);
  }

  50% {
    transform: scale(1.08);
  }
}

@media (max-width: 980px) {
  .main-nav {
    display: none;
  }

  .hero,
  .split,
  .contact-section {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
  }

  .teacher-showcase {
    min-height: 560px;
    max-width: 620px;
  }

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

  .teacher-card {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .site-header {
    gap: 12px;
  }

  .brand span {
    display: none;
  }

  .header-cta {
    min-height: 42px;
    padding: 0 14px;
    font-size: 0.86rem;
  }

  /* Điện thoại: chip chào mừng thu về CHỈ avatar tròn (vẫn là link về dashboard),
     tránh tên dài đẩy tràn header. Nút "Vào học" bên cạnh vẫn còn. */
  .header-welcome {
    padding: 3px;
    border-color: transparent;
    background: transparent;
  }

  .header-welcome-text {
    display: none;
  }

  .header-avatar {
    width: 40px;
    height: 40px;
  }

  .hero-stats,
  .path-grid,
  .teacher-grid {
    grid-template-columns: 1fr;
  }

  .teacher-showcase {
    min-height: 470px;
  }

  .hero-teacher {
    width: min(310px, 78vw);
  }

  .hero-teacher-secondary {
    width: min(210px, 52vw);
  }

  .hero-teacher div {
    min-width: 132px;
    padding: 10px 12px;
  }

  .hero-actions {
    display: grid;
  }

  .hero-actions a {
    width: 100%;
  }

  .path-card {
    min-height: auto;
  }

  .feature-item {
    grid-template-columns: 1fr;
  }

  .site-footer {
    display: grid;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }

  .flip-card.is-flipped .flip-inner {
    transform: none;
  }
}

/* =========================================================
   LUYỆN TẬP ONLINE — quiz + flashcard (section mới)
   Nền sáng đồng nhất; phân vùng bằng bố cục & viền.
   ========================================================= */
.practice-section {
  scroll-margin-top: 84px;
}

.practice-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(18px, 3vw, 28px);
  margin-top: 8px;
}

.practice-card {
  display: flex;
  flex-direction: column;
  gap: 16px;
  padding: clamp(22px, 3vw, 32px);
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #ffffff;
  box-shadow: 0 18px 44px rgba(7, 56, 115, 0.07);
}

.practice-card > .eyebrow {
  margin: 0;
}

.practice-card h3 {
  margin: 0;
  color: var(--navy);
  font-size: clamp(1.25rem, 2.4vw, 1.6rem);
  line-height: 1.2;
}

.practice-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.98rem;
  line-height: 1.7;
}

.practice-cta {
  align-self: flex-start;
  margin-top: 4px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--orange);
  font-weight: 700;
  font-size: 0.95rem;
}
.practice-cta::after {
  content: "→";
  transition: transform 200ms ease;
}
.practice-card:hover .practice-cta::after {
  transform: translateX(4px);
}

/* --- Flashcard lật (signature) --- */
.flip-demo {
  perspective: 1100px;
  margin-top: 2px;
}
.flip-card {
  width: 100%;
  height: 190px;
  border: 0;
  padding: 0;
  background: transparent;
  cursor: pointer;
  font-family: inherit;
}
.flip-inner {
  display: block;
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform 620ms cubic-bezier(0.2, 0.7, 0.2, 1);
}
.flip-card.is-flipped .flip-inner {
  transform: rotateY(180deg);
}
.flip-face {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border-radius: 16px;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  padding: 20px;
  text-align: center;
}
.flip-front {
  background:
    radial-gradient(circle at 20% 15%, rgba(253, 95, 13, 0.14), transparent 45%),
    var(--cream);
  border: 1px solid rgba(253, 95, 13, 0.24);
  transform: rotateY(0deg) translateZ(1px);
}
.flip-front .flip-word {
  color: var(--navy);
  font-size: 1.9rem;
  font-weight: 800;
}
.flip-front .flip-ipa {
  color: var(--muted);
  font-size: 0.95rem;
}
.flip-hint {
  position: absolute;
  right: 12px;
  bottom: 10px;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  opacity: 0.7;
}
.flip-back {
  background: var(--navy);
  color: #eaf1fb;
  transform: rotateY(180deg) translateZ(1px);
  border: 1px solid var(--navy);
}
.flip-back .flip-mean {
  font-size: 1.35rem;
  font-weight: 700;
  color: #ffffff;
}
.flip-back .flip-ex {
  font-size: 0.9rem;
  line-height: 1.55;
  color: #b9cfea;
}

/* --- Quiz demo (mini, tương tác bằng radio thuần CSS) --- */
.quiz-demo {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.quiz-q {
  margin: 0 0 4px;
  font-weight: 700;
  color: var(--ink);
}
.quiz-opt {
  display: flex;
  align-items: center;
  gap: 11px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 11px;
  cursor: pointer;
  transition: border-color 160ms ease, background 160ms ease;
}
.quiz-opt:hover {
  border-color: #b9cce6;
  background: var(--soft);
}
.quiz-opt input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}
.quiz-dot {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 2px solid var(--line);
  display: grid;
  place-items: center;
  transition: border-color 160ms ease;
}
.quiz-dot::after {
  content: "";
  width: 9px;
  height: 9px;
  border-radius: 50%;
  transform: scale(0);
  transition: transform 160ms ease;
}
.quiz-opt span.quiz-label {
  font-size: 0.96rem;
  color: var(--ink);
}
/* đáp án đúng */
.quiz-opt.correct input:checked ~ .quiz-dot {
  border-color: #1b7a43;
}
.quiz-opt.correct input:checked ~ .quiz-dot::after {
  background: #1b7a43;
  transform: scale(1);
}
.quiz-opt.correct input:checked ~ .quiz-verdict {
  color: #1b7a43;
}
/* đáp án sai */
.quiz-opt.wrong input:checked ~ .quiz-dot {
  border-color: var(--orange-dark);
}
.quiz-opt.wrong input:checked ~ .quiz-dot::after {
  background: var(--orange-dark);
  transform: scale(1);
}
.quiz-opt.wrong input:checked ~ .quiz-verdict {
  color: var(--orange-dark);
}
.quiz-verdict {
  margin-left: auto;
  font-size: 0.82rem;
  font-weight: 700;
  opacity: 0;
}
.quiz-opt input:checked ~ .quiz-verdict {
  opacity: 1;
}

/* =========================================================
   THI THỬ IELTS — băng 4 kỹ năng (section mới)
   ========================================================= */
.mock-section {
  scroll-margin-top: 84px;
}
.mock-band {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  margin: 4px 0 30px;
}
.mock-skill {
  padding: 20px 18px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #ffffff;
  transition: transform 200ms ease, box-shadow 200ms ease;
}
.mock-skill:hover {
  transform: translateY(-4px);
  box-shadow: 0 14px 30px rgba(7, 56, 115, 0.1);
}
.mock-ico {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: 12px;
  background: rgba(13, 74, 143, 0.09);
  color: var(--navy);
  font-size: 1.2rem;
  margin-bottom: 12px;
}
.mock-skill h3 {
  margin: 0 0 4px;
  color: var(--navy);
  font-size: 1.05rem;
}
.mock-skill p {
  margin: 0;
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.55;
}
.mock-cta-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
}
.mock-note {
  color: var(--muted);
  font-size: 0.9rem;
}

@media (max-width: 760px) {
  .practice-grid {
    grid-template-columns: 1fr;
  }
  .mock-band {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 440px) {
  .mock-band {
    grid-template-columns: 1fr;
  }
}

/* ===== Thanh progress khi chuyển trang ===== */
.route-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0;
  z-index: 2000;
  background: linear-gradient(90deg, var(--orange, #fd5f0d), #ffb066);
  box-shadow: 0 0 10px rgba(253, 95, 13, 0.7);
  border-radius: 0 3px 3px 0;
  opacity: 0;
  transition: width 180ms ease, opacity 260ms ease;
  pointer-events: none;
}

.route-progress.is-active {
  opacity: 1;
}

@media (prefers-reduced-motion: reduce) {
  .route-progress {
    transition: opacity 200ms ease;
  }
}

/* ============================================================
   LANDING V2 (/landing-v2) — animation layer (motion+gsap+lenis).
   Theo dataielts/stepielts-animation-spec.md. Mọi class prefix lv2-
   hoặc scope trong section riêng, KHÔNG đụng trang chủ hiện tại.
   Framer Motion tự lo opacity/transform inline — CSS ở đây chỉ lo
   những gì Framer không làm: 3D flip, ring, scroll-line, states.
   ============================================================ */

/* --- Header sticky (spec 5.11) --- */
.lv2-header {
  background: rgba(255, 255, 255, 0.72);
  transition: box-shadow 300ms ease, background-color 300ms ease,
    padding 300ms ease, backdrop-filter 300ms ease;
}
.lv2-header .main-nav {
  color: var(--ink);
  font-weight: 700;
  font-size: 1rem;
}
.lv2-header .main-nav a {
  padding: 6px 2px;
}
.lv2-header .brand span {
  font-weight: 800;
}
.lv2-header .brand img {
  transition: transform 300ms ease;
}
.lv2-header .header-login {
  font-weight: 700;
  color: var(--navy);
}
.lv2-header .header-cta {
  font-weight: 800;
  box-shadow: 0 8px 20px rgba(253, 95, 13, 0.28);
}
.lv2-header.lv2-scrolled {
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 8px 24px rgba(7, 56, 115, 0.1);
  border-bottom-color: transparent;
  padding-top: 10px;
  padding-bottom: 10px;
}
.lv2-header.lv2-scrolled .brand img {
  transform: scale(0.92);
}

/* --- Hero heading char-by-char mask (spec 5.2) --- */
.lv2-heading {
  display: inline-flex;
  flex-wrap: wrap;
}
.lv2-heading-mask {
  display: inline-block;
  overflow: hidden;
  vertical-align: top;
  line-height: 1.05;
}
.lv2-heading-ch {
  display: inline-block;
  white-space: pre;
}

/* --- Card giáo viên nghiêng nhẹ (spec 5.2 ambient) --- */
.lv2-hero .hero-teacher-main {
  transform: rotate(-2deg);
}
.lv2-hero .hero-teacher-secondary {
  transform: rotate(1.5deg);
}
/* khi có parallax inline (motion set x/y) vẫn giữ nghiêng qua CSS var fallback:
   Framer ghi transform inline nên nghiêng trên phải để ở phần tử trong. */
.lv2-hero .hero-teacher > img {
  display: block;
}

/* ============================================================
   Lộ trình 4 bước — scroll-line SVG (spec 5.3, SIGNATURE)
   ============================================================ */
.roadmap-section {
  overflow: hidden;
}
.roadmap {
  position: relative;
  margin-top: 40px;
}
.roadmap-line {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
}
.roadmap-line-track,
.roadmap-line-fill {
  fill: none;
  stroke-width: 3;
  stroke-linecap: round;
  vector-effect: non-scaling-stroke;
}
.roadmap-line-track {
  stroke: rgba(7, 56, 115, 0.12);
}
.roadmap-line-fill {
  stroke: var(--orange);
}
.roadmap-steps {
  position: relative;
  z-index: 1;
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.roadmap-step {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 14px;
  padding: 24px 20px;
  background: #fff;
  border: 1px solid rgba(7, 56, 115, 0.08);
  border-radius: 18px;
  box-shadow: 0 6px 18px rgba(7, 56, 115, 0.04);
  transition: border-color 400ms ease, box-shadow 400ms ease,
    transform 400ms ease, opacity 400ms ease;
  opacity: 0.62;
  transform: translateY(16px);
}
.roadmap-step.is-active {
  opacity: 1;
  transform: translateY(0);
  border-color: rgba(7, 56, 115, 0.22);
  box-shadow: 0 12px 30px rgba(7, 56, 115, 0.1);
}
.roadmap-badge {
  display: inline-grid;
  place-items: center;
  flex: 0 0 auto;
  width: 52px;
  height: 52px;
  border-radius: 50%;
  font-weight: 800;
  font-size: 1.15rem;
  color: rgba(7, 56, 115, 0.55);
  background: #fff;
  border: 2px solid rgba(7, 56, 115, 0.18);
  transition: color 300ms ease, border-color 300ms ease, background 300ms ease,
    transform 320ms cubic-bezier(0.16, 1, 0.3, 1);
}
.roadmap-step.is-active .roadmap-badge {
  color: #fff;
  background: var(--orange);
  border-color: var(--orange);
  animation: lv2-badge-pop 520ms cubic-bezier(0.16, 1, 0.3, 1);
}
@keyframes lv2-badge-pop {
  0% { transform: scale(1); }
  45% { transform: scale(1.12); }
  100% { transform: scale(1); }
}
.roadmap-body h3 {
  margin: 0 0 6px;
}
.roadmap-body p {
  margin: 0;
  color: var(--muted, #52607a);
  font-size: 0.96rem;
  line-height: 1.55;
}

/* Mobile: đường dọc bên trái, thẻ xếp cột */
.roadmap-vertical .roadmap-steps {
  grid-template-columns: 1fr;
  gap: 18px;
  padding-left: 8px;
}
.roadmap-vertical .roadmap-step {
  flex-direction: row;
  align-items: center;
}

/* ============================================================
   Quiz demo auto-play (spec 5.5) — states điều bằng JS, không :checked
   ============================================================ */
.quiz-opt {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  border: 1px solid rgba(7, 56, 115, 0.12);
  border-radius: 12px;
  background: #fff;
  transition: background 340ms ease, border-color 340ms ease, opacity 340ms ease;
}
.quiz-opt .quiz-dot {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 2px solid rgba(7, 56, 115, 0.28);
  flex: 0 0 auto;
  position: relative;
  transition: border-color 300ms ease, background 300ms ease;
}
.quiz-opt .quiz-label {
  font-weight: 600;
  flex: 1;
}
.quiz-opt .quiz-verdict {
  font-size: 0.82rem;
  font-weight: 700;
  opacity: 0;
  transform: translateX(6px);
  transition: opacity 300ms ease, transform 300ms ease;
}
/* con trỏ giả: highlight ring khi "point" */
.quiz-opt.is-point {
  border-color: rgba(253, 95, 13, 0.55);
  box-shadow: 0 0 0 3px rgba(253, 95, 13, 0.14);
}
/* graded: đáp án đúng */
.quiz-opt.correct.is-graded {
  background: rgba(34, 160, 90, 0.1);
  border-color: rgba(34, 160, 90, 0.5);
}
.quiz-opt.correct.is-graded .quiz-dot {
  border-color: #22a05a;
  background: #22a05a;
}
.quiz-opt.correct.is-graded .quiz-dot::after {
  content: "✓";
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  color: #fff;
  font-size: 0.7rem;
  font-weight: 900;
  animation: lv2-tick-pop 380ms cubic-bezier(0.16, 1, 0.3, 1);
}
@keyframes lv2-tick-pop {
  0% { transform: scale(0.4); }
  60% { transform: scale(1.15); }
  100% { transform: scale(1); }
}
.quiz-opt.correct.is-graded .quiz-verdict {
  opacity: 1;
  transform: none;
  color: #1c8a4c;
}
/* graded: đáp án sai mờ */
.quiz-opt.is-dim {
  opacity: 0.45;
}
.quiz-opt.is-dim .quiz-verdict {
  opacity: 1;
  transform: none;
  color: var(--muted, #52607a);
}

/* ============================================================
   Thi thử — progress ring (spec 5.6)
   ============================================================ */
.mock-ico-wrap {
  position: relative;
  display: inline-grid;
  place-items: center;
  width: 64px;
  height: 64px;
}
.mock-skill {
  transition: box-shadow 260ms ease;
}
.mock-skill .mock-ico {
  font-size: 1.7rem;
  display: inline-block;
  transition: transform 260ms cubic-bezier(0.16, 1, 0.3, 1);
}
.mock-skill:hover .mock-ico {
  transform: scale(1.1);
}
.mock-skill:hover {
  box-shadow: 0 16px 36px rgba(7, 56, 115, 0.12);
}

/* ============================================================
   Flashcard 3D flip (spec 5.4) — bổ sung cho .flip-* có sẵn
   ============================================================ */
.flip-demo {
  perspective: 1200px;
}
.flip-card {
  transform-style: preserve-3d;
}
.flip-inner {
  transform-style: preserve-3d;
}
.flip-face {
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}
.flip-card:hover {
  transform: translateY(-4px);
}

/* ============================================================
   Reduced-motion — TẮT toàn bộ motion (spec ràng buộc #4)
   Framer Motion tự bỏ animate khi component đọc useReducedMotion,
   phần còn lại (CSS transition/animation) tắt ở đây.
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  .lv2 *,
  .lv2 *::before,
  .lv2 *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .roadmap-step {
    opacity: 1;
    transform: none;
  }
  .roadmap-line-fill {
    stroke-dashoffset: 0 !important;
  }
}

/* ============================================================
   Form đăng ký v2 (spec 5.10) — floating label, shake, submit
   ============================================================ */
.lv2-lead {
  display: flex;
  flex-direction: column;
  gap: 18px;
}
.lv2-field {
  position: relative;
}
.lv2-field input,
.lv2-field select,
.lv2-field textarea {
  width: 100%;
  padding: 20px 14px 8px;
  border: 1.5px solid rgba(7, 56, 115, 0.16);
  border-radius: 12px;
  background: #fff;
  font: inherit;
  color: var(--ink);
  transition: border-color 200ms ease, box-shadow 200ms ease;
}
.lv2-field textarea {
  resize: vertical;
}
.lv2-field label {
  position: absolute;
  left: 14px;
  top: 14px;
  color: var(--muted, #6b7688);
  pointer-events: none;
  transition: transform 200ms ease, color 200ms ease, font-size 200ms ease;
  transform-origin: left top;
  background: transparent;
}
/* floating: khi focus HOẶC đã có giá trị (:not(:placeholder-shown)) */
.lv2-field input:focus + label,
.lv2-field textarea:focus + label,
.lv2-field input:not(:placeholder-shown) + label,
.lv2-field textarea:not(:placeholder-shown) + label,
.lv2-field select:focus + label,
.lv2-field select:valid + label {
  transform: translateY(-9px) scale(0.78);
  color: var(--navy);
}
.lv2-field input:focus,
.lv2-field select:focus,
.lv2-field textarea:focus {
  outline: none;
  border-color: var(--navy);
  box-shadow: 0 0 0 3px rgba(7, 56, 115, 0.12);
}
/* trạng thái lỗi */
.lv2-field.has-error input,
.lv2-field.has-error select,
.lv2-field.has-error textarea {
  border-color: #d64545;
  box-shadow: 0 0 0 3px rgba(214, 69, 69, 0.12);
}
.lv2-field.has-error {
  animation-duration: 320ms;
  animation-timing-function: ease;
}
.lv2-err {
  display: block;
  margin-top: 6px;
  color: #c23b3b;
  font-size: 0.85rem;
  font-weight: 600;
}
/* shake: ±4px translateX (spec). 2 tên tương đương để re-trigger mỗi submit-lỗi */
@keyframes lv2-shake {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-4px); }
  40% { transform: translateX(4px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(4px); }
}
@keyframes lv2-shake-b {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-4px); }
  40% { transform: translateX(4px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(4px); }
}

/* nút submit: hover scale 1.02 + shadow, active scale 0.98, loading spinner, done tick */
.lv2-submit {
  position: relative;
  transition: transform 160ms ease, box-shadow 200ms ease, background-color 200ms ease;
}
.lv2-submit:hover:not(:disabled) {
  transform: scale(1.02);
  box-shadow: 0 12px 26px rgba(253, 95, 13, 0.32);
}
.lv2-submit:active:not(:disabled) {
  transform: scale(0.98);
}
.lv2-submit.is-loading .lv2-submit-label {
  padding-left: 24px;
}
.lv2-submit.is-loading .lv2-submit-label::before {
  content: "";
  position: absolute;
  left: calc(50% - 44px);
  top: 50%;
  width: 15px;
  height: 15px;
  margin-top: -7.5px;
  border: 2px solid rgba(255, 255, 255, 0.5);
  border-top-color: #fff;
  border-radius: 50%;
  animation: lv2-spin 700ms linear infinite;
}
@keyframes lv2-spin {
  to { transform: rotate(360deg); }
}
.lv2-submit.is-done {
  background: #1c8a4c;
}
.lv2-submit.is-done .lv2-submit-label::after {
  content: " ✓";
}

@media (prefers-reduced-motion: reduce) {
  .lv2-submit.is-loading .lv2-submit-label::before {
    animation: none;
  }
}

/* ============ Landing v2 — Brief 2 sections ============ */

/* Hero tick row */
.lv2-hero-ticks { list-style: none; margin: 28px 0 0; padding: 0; display: grid; gap: 12px; }
.lv2-hero-tick { display: flex; align-items: center; gap: 10px; font-size: 1.02rem; color: #1f2a44; }
.lv2-tick-ico { color: #fd5f0d; flex: 0 0 auto; }

/* §2 Vì sao chọn */
.lv2-why-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; margin-top: 36px; }
.lv2-why-card { background: #fff; border: 1px solid #e6ebf3; border-radius: 16px; padding: 28px 24px; display: flex; flex-direction: column; gap: 10px; }
.lv2-why-num { font-size: 0.85rem; font-weight: 700; color: #fd5f0d; letter-spacing: 0.08em; }
.lv2-why-card h3 { margin: 0; font-size: 1.14rem; color: #073873; }
.lv2-why-card p { margin: 0; color: #45505f; line-height: 1.65; font-size: 0.96rem; }
.lv2-why-card--ai { background: #073873; border-color: #073873; color: #fff; }
.lv2-why-card--ai .lv2-why-num { color: #ff8a4c; }
.lv2-why-card--ai h3 { color: #fff; }
.lv2-why-card--ai p { color: #cdd8ea; }
.lv2-why-ailink { margin-top: auto; color: #ff8a4c; font-weight: 600; text-decoration: none; font-size: 0.95rem; }
.lv2-why-ailink:hover { text-decoration: underline; }

/* §4 Nền tảng — cột trái 3 thẻ (hẹp ngang, cao đều = cột phải) + cột phải visual */
.lv2-plat-grid { display: grid; grid-template-columns: minmax(0, 0.72fr) minmax(0, 1.28fr); gap: 40px; align-items: stretch; margin-top: 36px; }
.lv2-plat-list { display: grid; grid-template-rows: repeat(3, 1fr); gap: 16px; }

.lv2-plat-item { position: relative; text-align: left; background: #fff; border: 1px solid #e6ebf3; border-radius: 14px; padding: 18px 20px 18px 24px; cursor: pointer; display: flex; flex-direction: column; justify-content: center; gap: 6px; transition: border-color .25s, box-shadow .25s; overflow: hidden; }
.lv2-plat-item:hover { border-color: #d9e1ee; }
.lv2-plat-item.is-active { border-color: #cfdcf0; box-shadow: 0 16px 40px -26px rgba(7,56,115,.4); }
.lv2-plat-item-tab { font-size: 0.75rem; font-weight: 700; letter-spacing: 0.06em; text-transform: uppercase; color: #fd5f0d; }
.lv2-plat-item-title { font-size: 1.06rem; font-weight: 700; color: #073873; line-height: 1.4; }

/* thanh progress cam chạy dọc mép trái thẻ active trong 10s (1 cạnh, gọn) */
.lv2-plat-progress { position: absolute; top: 0; left: 0; width: 3px; height: 100%; background: #fd5f0d; border-radius: 3px; transform: scaleY(0); transform-origin: top; animation: lv2-plat-fill 10s linear forwards; z-index: 2; }
@keyframes lv2-plat-fill { from { transform: scaleY(0); } to { transform: scaleY(1); } }

/* cột phải visual — CHIỀU CAO CỐ ĐỊNH để 3 thẻ trái KHÔNG nhảy khi đổi khối
   (demo Vocab và ảnh stack cao khác nhau → chốt cùng 1 min-height) */
.lv2-plat-visual { display: flex; align-items: stretch; justify-content: center; height: 410px; }
.lv2-plat-visual > * { width: 100%; }

/* khối demo Vocab: flashcard + quiz */
/* 2 demo-card cao bằng nhau + lấp đầy chiều cao cột (khớp lưới với 3 thẻ trái) */
.lv2-plat-demos { display: grid; grid-template-rows: 1fr 1fr; gap: 16px; width: 100%; height: 100%; }
.lv2-plat-demo-card { background: #fff; border: 1px solid #e6ebf3; border-radius: 16px; padding: 13px 16px; box-shadow: 0 18px 44px -30px rgba(7,56,115,.4); display: flex; flex-direction: column; justify-content: center; }
.lv2-plat-demo-tag { margin: 0 0 8px; font-size: 0.72rem; font-weight: 700; letter-spacing: 0.06em; text-transform: uppercase; color: #fd5f0d; }
/* thu nhỏ flashcard + quiz trong Platform cho đồng bộ chiều cao với các khối shots */
.lv2-plat-demos .flip-card { height: 106px; }
.lv2-plat-demos .quiz-demo { gap: 7px; }
.lv2-plat-demos .quiz-q { font-size: 14px; margin-bottom: 8px; }
.lv2-plat-demos .quiz-opt { padding: 8px 12px; font-size: 14px; }

/* khối shots: ảnh xếp chồng — lấp đầy chiều cao cột; là <button> bấm để phóng to */
.lv2-plat-stack { position: relative; width: 100%; height: 100%; border: 0; background: none; padding: 0; cursor: zoom-in; display: block; }
.lv2-plat-stack-img { position: absolute; border-radius: 14px; overflow: hidden; border: 1px solid #e6ebf3; box-shadow: 0 24px 60px -30px rgba(7,56,115,.45); background: #eef2f8; transition: top .4s cubic-bezier(.16,1,.3,1), bottom .4s cubic-bezier(.16,1,.3,1), left .4s cubic-bezier(.16,1,.3,1), right .4s cubic-bezier(.16,1,.3,1), width .4s cubic-bezier(.16,1,.3,1); }
.lv2-plat-stack-img img { display: block; width: 100%; height: auto; }
/* 2 ảnh xếp chéo — ảnh 0 trước (trên-trái), ảnh 1 sau (dưới-phải) */
.lv2-plat-stack--2 .lv2-plat-stack-img--0 { top: 4%; left: 0; width: 76%; z-index: 2; }
.lv2-plat-stack--2 .lv2-plat-stack-img--1 { bottom: 4%; right: 0; width: 66%; z-index: 1; }
/* hover: 2 ảnh ĐỔI CHỖ + z-index (ảnh sau trượt lên trước) */
.lv2-plat-stack--2.is-swapped .lv2-plat-stack-img--0 { top: auto; bottom: 4%; left: auto; right: 0; width: 66%; z-index: 1; }
.lv2-plat-stack--2.is-swapped .lv2-plat-stack-img--1 { bottom: auto; top: 4%; right: auto; left: 0; width: 76%; z-index: 2; }
/* 3 ảnh */
.lv2-plat-stack--3 .lv2-plat-stack-img--0 { top: 0; left: 0; width: 66%; z-index: 3; }
.lv2-plat-stack--3 .lv2-plat-stack-img--1 { top: 22%; right: 0; width: 60%; z-index: 2; }
.lv2-plat-stack--3 .lv2-plat-stack-img--2 { bottom: 0; left: 12%; width: 58%; z-index: 1; }

/* Lightbox phóng to */
.lv2-plat-lb { position: fixed; inset: 0; z-index: 100; background: rgba(7,20,40,.82); backdrop-filter: blur(5px); display: flex; align-items: center; justify-content: center; padding: 2vh 2vw; animation: lv2-lb-in .2s ease; }
@keyframes lv2-lb-in { from { opacity: 0; } to { opacity: 1; } }
.lv2-plat-lb-close { position: absolute; top: 18px; right: 22px; width: 46px; height: 46px; border-radius: 50%; border: 0; background: rgba(255,255,255,.16); color: #fff; font-size: 21px; cursor: pointer; transition: background .2s; z-index: 3; }
.lv2-plat-lb-close:hover { background: rgba(255,255,255,.3); }
/* stack THẬT TO — gần full màn */
.lv2-plat-lb-stack { position: relative; width: min(1500px, 96vw); height: 92vh; }
.lv2-plat-lb-img { position: absolute; border: 0; padding: 0; background: none; border-radius: 14px; overflow: hidden; box-shadow: 0 30px 90px -18px rgba(0,0,0,.65); cursor: pointer; transition: top .4s cubic-bezier(.16,1,.3,1), left .4s cubic-bezier(.16,1,.3,1), width .4s cubic-bezier(.16,1,.3,1), filter .3s; }
.lv2-plat-lb-img img { display: block; width: 100%; height: auto; }
/* 2 ảnh lệch chéo, ảnh trước RỘNG 86% màn; ảnh sau thò góc dưới-phải để click được */
.lv2-plat-lb-img.is-front { top: 0; left: 0; width: 86%; z-index: 2; }
.lv2-plat-lb-img.is-back { top: 22%; left: 14%; width: 86%; z-index: 1; filter: brightness(.72); cursor: zoom-in; }
.lv2-plat-lb-img.is-back:hover { filter: brightness(1); }

/* §5 AI */
.lv2-ai-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin-top: 36px; }
.lv2-ai-card { background: #fff; border: 1px solid #e6ebf3; border-radius: 16px; padding: 26px 24px; }
.lv2-ai-card h3 { margin: 0 0 14px; font-size: 1.18rem; color: #073873; }
.lv2-ai-card p { margin: 0; color: #45505f; line-height: 1.7; font-size: 0.96rem; }
.lv2-ai-note { margin-top: 28px; padding: 22px 26px; background: #f2f6fc; border-left: 4px solid #073873; border-radius: 12px; }
.lv2-ai-note p { margin: 0; color: #1f2a44; line-height: 1.7; }
.lv2-ai-note strong { color: #073873; }

/* mini-demo tra từ */
.lv2-lookup { position: relative; margin: 0 0 16px; padding: 18px; background: #f7f9fc; border: 1px solid #e6ebf3; border-radius: 12px; min-height: 96px; }
.lv2-lookup-text { margin: 0; color: #1f2a44; line-height: 1.7; font-size: 0.95rem; }
.lv2-lookup-word { position: relative; border-radius: 3px; transition: background .3s, color .3s; padding: 0 2px; }
.lv2-lookup-word.is-sel { background: #073873; color: #fff; }
.lv2-lookup-pop { position: absolute; left: 18px; bottom: 12px; background: #fff; border: 1px solid #d9e1ee; border-radius: 10px; padding: 10px 14px; box-shadow: 0 12px 30px -14px rgba(7,56,115,.5); display: flex; flex-direction: column; gap: 2px; font-size: 0.85rem; opacity: 0; transform: translateY(8px); pointer-events: none; transition: opacity .3s, transform .3s; }
.lv2-lookup-pop.is-show { opacity: 1; transform: translateY(0); }
.lv2-lookup-pop strong { color: #073873; }
.lv2-lookup-pop em { color: #fd5f0d; font-style: italic; }
.lv2-lookup-pop span { color: #45505f; }

/* §6 thi thử 3 bước */
.lv2-mock-steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin: 36px 0; }
.lv2-mock-step { background: #fff; border: 1px solid #e6ebf3; border-radius: 16px; padding: 26px 24px; }
.lv2-mock-num { display: inline-flex; align-items: center; justify-content: center; width: 40px; height: 40px; border-radius: 50%; background: #073873; color: #fff; font-weight: 700; margin-bottom: 14px; }
.lv2-mock-step h3 { margin: 0 0 8px; font-size: 1.12rem; color: #073873; }
.lv2-mock-step p { margin: 0; color: #45505f; line-height: 1.65; font-size: 0.95rem; }

/* form hint */
.lv2-form-hint { margin: 10px 0 0; font-size: 0.86rem; color: #6b7688; text-align: center; }

/* reduced-motion: mini-demo hiện trạng thái cuối */
@media (prefers-reduced-motion: reduce) {
  .lv2-lookup-word { background: #073873; color: #fff; }
  .lv2-lookup-pop { opacity: 1; transform: none; }
}

/* responsive */
@media (max-width: 1023px) {
  .lv2-why-grid { grid-template-columns: repeat(2, 1fr); }
  .lv2-ai-grid { grid-template-columns: 1fr; }
  .lv2-mock-steps { grid-template-columns: 1fr; }
  /* §4: xếp dọc, visual xuống dưới thẻ active */
  .lv2-plat-grid { grid-template-columns: 1fr; gap: 28px; }
  .lv2-plat-visual { min-height: 0; }
}
@media (max-width: 767px) {
  .lv2-why-grid { grid-template-columns: 1fr; }
  /* nav mobile rút 4 mục: ẩn AI (Vì sao chọn đã bỏ khỏi nav) */
  .lv2-header .main-nav a[href="#ai"] { display: none; }
  .lv2-plat-stack { aspect-ratio: 3 / 4; }
}