/* ============================================================
   DESIGN TOKENS
   ============================================================ */
:root {
  --red:        #C8302A;
  --red-dark:   #8B1F1A;
  --cream:      #F5EFE6;
  --black:      #1A1A1A;
  --grey:       #6B6B6B;
  --grey-light: #E4DAD0;

  --font-serif: 'Playfair Display', Georgia, serif;
  --font-sans:  'Be Vietnam Pro', system-ui, -apple-system, sans-serif;

  --max-w: 1200px;
  --pad-x: clamp(1.25rem, 5vw, 3rem);
  --section-y: clamp(80px, 10vw, 140px);
}

/* ============================================================
   RESET & BASE
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: var(--font-sans);
  background: var(--cream);
  color: var(--black);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { cursor: pointer; border: none; background: none; font: inherit; }
ul { list-style: none; }

/* ============================================================
   UTILITIES
   ============================================================ */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 var(--pad-x);
}

/* Scroll reveal */
.reveal {
  opacity: 0;
  transform: translateY(36px);
  transition: opacity 0.75s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.75s cubic-bezier(0.16, 1, 0.3, 1);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}
.reveal:nth-child(2) { transition-delay: 0.08s; }
.reveal:nth-child(3) { transition-delay: 0.16s; }
.reveal:nth-child(4) { transition-delay: 0.24s; }
.reveal:nth-child(5) { transition-delay: 0.32s; }
.reveal:nth-child(6) { transition-delay: 0.40s; }

/* Section labels */
.section-tag {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--red);
  margin-bottom: 1rem;
}
.section-tag.light { color: rgba(245, 239, 230, 0.55); }

.section-head {
  margin-bottom: clamp(3rem, 6vw, 5rem);
}

.section-title {
  font-family: var(--font-serif);
  font-size: clamp(2.2rem, 4.5vw, 3.5rem);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  padding: 0.85rem 1.75rem;
  border-radius: 3px;
  transition: background 0.2s, color 0.2s, border-color 0.2s, transform 0.15s;
  white-space: nowrap;
}
.btn:active { transform: scale(0.98); }

.btn-primary {
  background: var(--red);
  color: #fff;
}
.btn-primary:hover { background: var(--red-dark); }

.btn-outline {
  background: transparent;
  color: var(--black);
  border: 1.5px solid var(--black);
}
.btn-outline:hover {
  background: var(--black);
  color: var(--cream);
}

.btn-nav {
  background: var(--red);
  color: #fff;
  padding: 0.6rem 1.25rem;
  font-size: 0.82rem;
}
.btn-nav:hover { background: var(--red-dark); }

/* ============================================================
   NAV
   ============================================================ */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 1.1rem var(--pad-x);
  transition: background 0.35s ease, box-shadow 0.35s ease;
}

.nav.solid {
  background: var(--cream);
  box-shadow: 0 1px 0 var(--grey-light);
}

.nav-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-brand {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  flex-shrink: 0;
}

.nav-links {
  display: flex;
  gap: 2rem;
  margin-left: auto;
}

.nav-links a {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--grey);
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--black); }

.nav .btn-nav { margin-left: 1rem; }

/* ============================================================
   HERO
   ============================================================ */
.hero {
  min-height: 100svh;
  display: flex;
  align-items: center;
  padding: calc(80px + var(--section-y)) var(--pad-x) var(--section-y);
}

.hero-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  width: 100%;
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  gap: clamp(2.5rem, 6vw, 6rem);
}

.hero-logo-wrap {
  flex-shrink: 0;
}

.hero-logo {
  width: clamp(160px, 22vw, 260px);
  height: clamp(160px, 22vw, 260px);
  object-fit: contain;
  border-radius: 8px;
}

.hero-eyebrow {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--red);
  margin-bottom: 1.25rem;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(3rem, 6.5vw, 6rem);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -0.03em;
  margin-bottom: 1.75rem;
}

.hero-title em {
  font-style: italic;
  color: var(--red);
}

.hero-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem 0.75rem;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--grey);
  margin-bottom: 2.25rem;
}

/* ============================================================
   MARQUEE
   ============================================================ */
.marquee {
  overflow: hidden;
  border-top: 1px solid var(--grey-light);
  border-bottom: 1px solid var(--grey-light);
  padding: 0.85rem 0;
  background: var(--cream);
}

.marquee-track {
  display: flex;
  gap: 1.5rem;
  width: max-content;
  animation: marquee 28s linear infinite;
}

.marquee-track span {
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--grey);
  white-space: nowrap;
}

@keyframes marquee {
  from { transform: translateX(0); }
  to   { transform: translateX(-50%); }
}

/* ============================================================
   VÌ SAO BỨC XÚC
   ============================================================ */
.why {
  padding: var(--section-y) 0;
}

.why-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(2rem, 4vw, 3.5rem) clamp(3rem, 6vw, 6rem);
}

.why-item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1.5rem;
  align-items: start;
}

.why-num {
  font-family: var(--font-serif);
  font-size: clamp(3rem, 5vw, 4.5rem);
  font-weight: 900;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1.5px var(--grey-light);
  letter-spacing: -0.03em;
  flex-shrink: 0;
  user-select: none;
}

.why-body h3 {
  font-family: var(--font-serif);
  font-size: clamp(1.1rem, 1.8vw, 1.3rem);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: 0.65rem;
  letter-spacing: -0.01em;
}

.why-body p {
  font-size: 0.92rem;
  color: var(--grey);
  line-height: 1.7;
}

/* ============================================================
   KHOÁ HỌC
   ============================================================ */
.courses {
  padding: var(--section-y) 0;
  background: var(--black);
}

.courses .section-tag { color: rgba(245, 239, 230, 0.5); }

.courses .section-title {
  color: var(--cream);
}

.courses-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: rgba(255,255,255,0.07);
  border: 1px solid rgba(255,255,255,0.07);
}

.course-card {
  background: var(--black);
  padding: clamp(1.5rem, 3vw, 2.25rem);
  transition: background 0.2s;
}

.course-card:hover { background: #222; }

.course-level {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--red);
  border: 1px solid rgba(200, 48, 42, 0.4);
  padding: 0.2rem 0.55rem;
  border-radius: 2px;
  margin-bottom: 1rem;
}

.course-card h4 {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--cream);
  margin-bottom: 0.6rem;
  line-height: 1.3;
}

.course-card p {
  font-size: 0.85rem;
  color: rgba(245, 239, 230, 0.55);
  line-height: 1.7;
}

.courses-cta {
  margin-top: clamp(2.5rem, 5vw, 4rem);
  display: flex;
  align-items: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.courses-cta p {
  font-size: 0.9rem;
  color: rgba(245, 239, 230, 0.5);
}

.courses .btn-outline {
  color: var(--cream);
  border-color: rgba(245, 239, 230, 0.35);
  font-size: 0.85rem;
  padding: 0.75rem 1.5rem;
}

.courses .btn-outline:hover {
  background: var(--cream);
  color: var(--black);
  border-color: var(--cream);
}

/* ============================================================
   TESTIMONIALS
   ============================================================ */
.testimonials {
  padding: var(--section-y) 0;
  background: #111;
  color: var(--cream);
}

.testimonials .section-title { color: var(--cream); }

.testimonials-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(1.5rem, 3vw, 2.5rem);
}

.testimonial {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: 4px;
  padding: clamp(1.5rem, 3vw, 2.25rem);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.testimonial-quote-mark {
  font-family: var(--font-serif);
  font-size: 4rem;
  line-height: 0.7;
  color: var(--red);
  font-weight: 900;
  user-select: none;
}

.testimonial p {
  font-size: 0.95rem;
  line-height: 1.75;
  color: rgba(245, 239, 230, 0.75);
  flex: 1;
}

.testimonial-author {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(255,255,255,0.08);
}

.testimonial-author strong {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--cream);
}

.testimonial-author span {
  font-size: 0.78rem;
  color: rgba(245, 239, 230, 0.4);
  letter-spacing: 0.03em;
}

/* ============================================================
   GIẢNG VIÊN
   ============================================================ */
.teachers {
  padding: var(--section-y) 0;
}

.teachers-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(1.5rem, 3vw, 2.5rem);
}

.teacher-card {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.teacher-avatar {
  width: 64px;
  height: 64px;
  background: var(--red);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  flex-shrink: 0;
}

.teacher-info h4 {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.teacher-role {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--red);
  display: block;
  margin-bottom: 0.75rem;
}

.teacher-info p {
  font-size: 0.88rem;
  color: var(--grey);
  line-height: 1.7;
}

/* ============================================================
   HỌC PHÍ
   ============================================================ */
.pricing {
  padding: var(--section-y) 0;
  background: var(--cream);
  border-top: 1px solid var(--grey-light);
  border-bottom: 1px solid var(--grey-light);
}

.pricing-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: clamp(3rem, 6vw, 7rem);
  align-items: center;
}

.pricing-text .section-tag { margin-bottom: 0.75rem; }

.pricing-text h2 {
  font-family: var(--font-serif);
  font-size: clamp(2.2rem, 4vw, 3.2rem);
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin-bottom: 2rem;
}

.pricing-perks {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  margin-bottom: 2.25rem;
}

.pricing-perks li {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  font-size: 0.9rem;
  line-height: 1.5;
  color: var(--grey);
}

.pricing-perks svg { flex-shrink: 0; margin-top: 2px; }

.pricing-card {
  background: var(--black);
  color: var(--cream);
  padding: clamp(2rem, 4vw, 3rem);
  border-radius: 6px;
  min-width: 280px;
  flex-shrink: 0;
}

.pricing-label {
  display: block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: rgba(245, 239, 230, 0.45);
  margin-bottom: 1.25rem;
}

.pricing-amount {
  display: flex;
  align-items: baseline;
  gap: 0.25rem;
  margin-bottom: 0.25rem;
}

.pricing-currency {
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--red);
}

.pricing-number {
  font-family: var(--font-serif);
  font-size: clamp(2.5rem, 4vw, 3.25rem);
  font-weight: 900;
  letter-spacing: -0.03em;
  line-height: 1;
}

.pricing-per {
  display: block;
  font-size: 0.82rem;
  color: rgba(245, 239, 230, 0.45);
  margin-bottom: 1.75rem;
}

.pricing-divider {
  border: none;
  border-top: 1px solid rgba(255,255,255,0.1);
  margin-bottom: 1.5rem;
}

.pricing-details {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.pricing-detail-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
  font-size: 0.82rem;
}

.pricing-detail-row span { color: rgba(245, 239, 230, 0.45); }
.pricing-detail-row strong { color: var(--cream); font-weight: 500; }

/* ============================================================
   FAQ
   ============================================================ */
.faq { padding: var(--section-y) 0; }

.faq-list {
  max-width: 780px;
  display: flex;
  flex-direction: column;
  gap: 0;
  border-top: 1px solid var(--grey-light);
}

.faq-item { border-bottom: 1px solid var(--grey-light); }

.faq-q {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1.5rem;
  padding: 1.4rem 0;
  font-size: 0.97rem;
  font-weight: 500;
  text-align: left;
  color: var(--black);
  transition: color 0.2s;
}

.faq-q:hover { color: var(--red); }

.faq-q[aria-expanded="true"] { color: var(--red); }

.faq-icon {
  flex-shrink: 0;
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  color: var(--grey);
}

.faq-q[aria-expanded="true"] .faq-icon {
  transform: rotate(180deg);
  color: var(--red);
}

.faq-a {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 0.35s cubic-bezier(0.16, 1, 0.3, 1);
}

.faq-a.open { grid-template-rows: 1fr; }

.faq-a > p {
  overflow: hidden;
  font-size: 0.9rem;
  color: var(--grey);
  line-height: 1.75;
  padding-bottom: 1.4rem;
}

/* ============================================================
   ĐĂNG KÝ
   ============================================================ */
.register {
  padding: var(--section-y) 0;
  background: var(--black);
  color: var(--cream);
}

.register-inner {
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  gap: clamp(3rem, 6vw, 7rem);
  align-items: start;
}

.register-text h2 {
  font-family: var(--font-serif);
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 900;
  line-height: 1.05;
  letter-spacing: -0.03em;
  margin-bottom: 1.25rem;
}

.register-text p {
  font-size: 0.92rem;
  color: rgba(245, 239, 230, 0.6);
  line-height: 1.7;
  margin-bottom: 1rem;
}

.register-note {
  font-size: 0.8rem !important;
  color: rgba(245, 239, 230, 0.35) !important;
  line-height: 1.6 !important;
}

/* Form */
.register-form {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.form-group label {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: rgba(245, 239, 230, 0.55);
}

.form-group label span[aria-hidden] {
  color: var(--red);
  margin-left: 0.15em;
}

.optional {
  text-transform: none;
  letter-spacing: 0;
  font-weight: 400;
  color: rgba(245, 239, 230, 0.3) !important;
}

.form-group input,
.form-group textarea,
.form-group select {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 3px;
  padding: 0.8rem 1rem;
  color: var(--cream);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  transition: border-color 0.2s, background 0.2s;
  width: 100%;
  appearance: none;
  -webkit-appearance: none;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
  color: rgba(245, 239, 230, 0.25);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: rgba(245, 239, 230, 0.5);
  background: rgba(255,255,255,0.09);
}

.form-group.error input,
.form-group.error textarea,
.form-group.error select {
  border-color: var(--red);
}

.field-error {
  font-size: 0.75rem;
  color: #e87070;
  display: none;
}

.form-group.error .field-error { display: block; }

.select-wrap {
  position: relative;
}

.select-wrap select {
  padding-right: 2.5rem;
  cursor: pointer;
}

.select-wrap select option {
  background: #1A1A1A;
  color: var(--cream);
}

.select-arrow {
  position: absolute;
  right: 0.85rem;
  top: 50%;
  transform: translateY(-50%);
  pointer-events: none;
  color: rgba(245, 239, 230, 0.35);
}

.form-group textarea {
  resize: vertical;
  min-height: 90px;
}

.btn-submit {
  position: relative;
  width: 100%;
  justify-content: center;
  padding: 1rem;
  font-size: 0.95rem;
  margin-top: 0.25rem;
}

.btn-loading-text { display: none; }

.btn-submit.loading .btn-default-text { display: none; }
.btn-submit.loading .btn-loading-text { display: inline; }
.btn-submit.loading { opacity: 0.7; cursor: not-allowed; }

.form-success {
  display: none;
  align-items: flex-start;
  gap: 1rem;
  background: rgba(200, 48, 42, 0.1);
  border: 1px solid rgba(200, 48, 42, 0.3);
  border-radius: 4px;
  padding: 1.25rem;
  margin-top: 0.5rem;
}

.form-success.visible { display: flex; }

.form-success strong {
  display: block;
  font-size: 0.9rem;
  color: var(--cream);
  margin-bottom: 0.25rem;
}

.form-success p {
  font-size: 0.82rem;
  color: rgba(245, 239, 230, 0.55);
  margin-bottom: 0 !important;
}

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
  background: #0e0e0e;
  color: var(--cream);
  padding: clamp(3rem, 6vw, 5rem) 0 2rem;
}

.footer-inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr auto;
  gap: clamp(2rem, 4vw, 4rem);
  align-items: start;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid rgba(255,255,255,0.07);
  margin-bottom: 2rem;
}

.footer-name {
  display: block;
  font-family: var(--font-serif);
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 0.6rem;
}

.footer-brand p {
  font-size: 0.82rem;
  color: rgba(245, 239, 230, 0.4);
  line-height: 1.7;
}

.footer-nav {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.footer-nav a {
  font-size: 0.85rem;
  color: rgba(245, 239, 230, 0.5);
  transition: color 0.2s;
}

.footer-nav a:hover { color: var(--cream); }

.social-link {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 0.85rem;
  color: rgba(245, 239, 230, 0.5);
  transition: color 0.2s;
}

.social-link:hover { color: var(--cream); }

.footer-bottom p {
  font-size: 0.75rem;
  color: rgba(245, 239, 230, 0.25);
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 1024px) {
  .why-grid { grid-template-columns: 1fr; gap: 2.5rem; }
  .courses-grid { grid-template-columns: repeat(2, 1fr); }
  .teachers-grid { grid-template-columns: 1fr 1fr; }
  .pricing-inner { grid-template-columns: 1fr; }
  .pricing-card { min-width: unset; max-width: 420px; }
  .register-inner { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr 1fr; }
  .footer-social { grid-column: 1 / -1; }
}

@media (max-width: 768px) {
  .hero-inner {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 2rem;
  }
  .hero-logo-wrap { display: flex; justify-content: center; }
  .hero-logo { width: clamp(120px, 40vw, 180px); height: clamp(120px, 40vw, 180px); }
  .hero-meta { justify-content: center; }

  .nav-links { display: none; }

  .why-item { grid-template-columns: auto 1fr; }
  .courses-grid { grid-template-columns: 1fr; }
  .courses-cta { flex-direction: column; align-items: flex-start; }
  .testimonials-grid { grid-template-columns: 1fr; }
  .teachers-grid { grid-template-columns: 1fr; }
  .teacher-card { flex-direction: row; }
  .form-row { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
  .hero-title { font-size: clamp(2.4rem, 10vw, 3rem); }
  .why-item { grid-template-columns: 1fr; }
  .why-num { font-size: 2.5rem; }
  .teacher-card { flex-direction: column; }
  .pricing-inner { gap: 2rem; }
}

/* ============================================================
   REDUCED MOTION
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .marquee-track { animation: none; }
  html { scroll-behavior: auto; }
}