/* ============================================================
   GIA SƯ KIẾN VINH – STYLE.CSS
   Color palette: Deep navy + warm gold + soft sky blue
   Font: Playfair Display (display) + Be Vietnam Pro (body)
   ============================================================ */

:root {
  --navy: #0f2c57;
  --navy-mid: #1a3f7a;
  --gold: #e6a817;
  --gold-lt: #f5c842;
  --sky: #e8f4fd;
  --sky-mid: #c9e6f7;
  --white: #ffffff;
  --gray-50: #f8f9fb;
  --gray-100: #eef1f6;
  --gray-400: #8899aa;
  --gray-600: #4a5f75;
  --gray-800: #1e2f42;
  --zalo: #0068ff;

  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --shadow-sm: 0 2px 12px rgba(15, 44, 87, .08);
  --shadow-md: 0 8px 32px rgba(15, 44, 87, .13);
  --shadow-lg: 0 16px 48px rgba(15, 44, 87, .18);
  --transition: .3s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Be Vietnam Pro', sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--gray-800);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
}

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

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

/* UTILITY */
.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 24px;
}

strong {
  font-weight: 700;
}

/* ── HEADER ── */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: var(--transition);
}

.header.scrolled {
  border-bottom-color: var(--gray-100);
  box-shadow: var(--shadow-sm);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo-icon {
  font-size: 24px;
  color: var(--gold);
  filter: drop-shadow(0 0 6px rgba(230, 168, 23, .4));
}

.logo-title {
  display: block;
  font-family: 'Playfair Display', serif;
  font-size: 1.5rem;
  font-weight: 900;
  color: var(--navy);
  line-height: 1.1;
}

.logo-sub {
  display: block;
  font-size: 1rem;
  font-weight: 500;
  color: var(--gold);
  letter-spacing: .06em;
}

.nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav a {
  font-size: .9rem;
  font-weight: 500;
  color: var(--gray-600);
  transition: color var(--transition);
}

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

.btn-nav {
  background: var(--navy);
  color: var(--white) !important;
  padding: 9px 22px;
  border-radius: 50px;
  font-weight: 600 !important;
  transition: background var(--transition), transform var(--transition) !important;
}

.btn-nav:hover {
  background: var(--navy-mid) !important;
  transform: translateY(-1px);
}

/* ── BUTTONS ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  padding: 14px 28px;
  border-radius: 50px;
  font-family: 'Be Vietnam Pro', sans-serif;
  font-size: .95rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform .2s, box-shadow .2s, background .2s;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-primary {
  background: var(--gold);
  color: var(--navy);
}

.btn-primary:hover {
  background: var(--gold-lt);
}

.btn-zalo {
  background: var(--zalo);
  color: var(--white);
}

.btn-zalo:hover {
  background: #0057d0;
}

.btn-zalo-lg {
  display: inline-block;
  padding: 13px 30px;
  border-radius: 50px;
  background: var(--zalo);
  color: var(--white);
  font-weight: 700;
  font-size: .95rem;
  transition: var(--transition);
}

.btn-zalo-lg:hover {
  background: #0057d0;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

/* ── HERO ── */
.hero {
  position: relative;
  padding: 140px 0 80px;
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-mid) 60%, #1e5294 100%);
  overflow: hidden;
}

.hero-bg-shapes {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.shape {
  position: absolute;
  border-radius: 50%;
  opacity: .08;
  background: var(--gold);
}

.shape-1 {
  width: 480px;
  height: 480px;
  top: -140px;
  right: -100px;
}

.shape-2 {
  width: 260px;
  height: 260px;
  bottom: -80px;
  left: 10%;
  background: var(--sky-mid);
  opacity: .12;
}

.shape-3 {
  width: 140px;
  height: 140px;
  top: 60%;
  right: 18%;
  background: var(--white);
  opacity: .05;
}

.hero-content {
  position: relative;
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 22px;
  max-width: 720px;
}

.hero-badge {
  background: rgba(230, 168, 23, .18);
  border: 1px solid rgba(230, 168, 23, .4);
  color: var(--gold-lt);
  padding: 7px 18px;
  border-radius: 50px;
  font-size: .85rem;
  font-weight: 600;
  letter-spacing: .04em;
}

.hero-title {
  font-family: 'Playfair Display', serif;
  font-size: clamp(2.4rem, 5vw, 3.6rem);
  font-weight: 900;
  color: var(--white);
  line-height: 1.15;
}

.hero-title .highlight {
  color: var(--gold);
  display: block;
}

.hero-desc {
  font-size: 1.05rem;
  color: rgba(255, 255, 255, .82);
  max-width: 560px;
  line-height: 1.75;
}

.hero-desc strong {
  color: var(--gold-lt);
}

.hero-cta {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.hero-stats {
  display: flex;
  align-items: center;
  gap: 28px;
  margin-top: 16px;
  padding-top: 28px;
  border-top: 1px solid rgba(255, 255, 255, .15);
}

.stat {
  text-align: center;
}

.stat-num {
  display: block;
  font-family: 'Playfair Display', serif;
  font-size: 2rem;
  font-weight: 900;
  color: var(--gold);
  line-height: 1;
}

.stat-label {
  font-size: .8rem;
  color: rgba(255, 255, 255, .65);
  margin-top: 4px;
  display: block;
  font-weight: 500;
}

.stat-divider {
  width: 1px;
  height: 44px;
  background: rgba(255, 255, 255, .2);
}

/* ── SECTIONS ── */
.section {
  padding: 90px 0;
}

.section-alt {
  background: var(--gray-50);
}

.section-label {
  display: inline-block;
  background: var(--sky);
  color: var(--navy-mid);
  font-size: .8rem;
  font-weight: 700;
  letter-spacing: .1em;
  text-transform: uppercase;
  padding: 5px 16px;
  border-radius: 50px;
  margin-bottom: 14px;
}

.section-title {
  font-family: 'Playfair Display', serif;
  font-size: clamp(1.8rem, 3.5vw, 2.5rem);
  font-weight: 900;
  color: var(--navy);
  line-height: 1.2;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 1rem;
  color: var(--gray-600);
  margin-bottom: 48px;
  max-width: 580px;
}

/* ── INTRO GRID ── */
.intro-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: start;
}

.intro-text {
  display: flex;
  flex-direction: column;
  gap: 18px;
  font-size: 1rem;
  color: var(--gray-600);
  line-height: 1.8;
  text-align: justify;
}

.address-card {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  background: var(--sky);
  border-left: 4px solid var(--gold);
  border-radius: var(--radius-sm);
  padding: 18px 20px;
  font-size: .95rem;
  line-height: 1.7;
  color: var(--gray-800);
  margin-top: 8px;
}

.address-icon {
  font-size: 1.3rem;
  flex-shrink: 0;
  margin-top: 2px;
}

.intro-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}

.value-card {
  background: var(--white);
  border: 1.5px solid var(--gray-100);
  border-radius: var(--radius-md);
  padding: 22px 18px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition), border-color var(--transition);
}

.value-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--sky-mid);
  transform: translateY(-3px);
}

.value-icon {
  font-size: 1.8rem;
  display: block;
  margin-bottom: 10px;
}

.value-card h3 {
  font-size: .95rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 6px;
}

.value-card p {
  font-size: .85rem;
  color: var(--gray-600);
  line-height: 1.6;
}

/* ── SUBJECTS GRID ── */
.subjects-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-bottom: 40px;
}

.subject-card {
  background: var(--white);
  border: 1.5px solid var(--gray-100);
  border-radius: var(--radius-md);
  padding: 26px 20px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.subject-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--gold);
}

.subject-icon {
  font-size: 2.2rem;
  display: block;
  margin-bottom: 12px;
}

.subject-card h3 {
  font-size: .95rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 8px;
}

.subject-card p {
  font-size: .82rem;
  color: var(--gray-600);
  line-height: 1.55;
}

.levels-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.level-tag {
  background: var(--gray-100);
  color: var(--gray-600);
  padding: 8px 20px;
  border-radius: 50px;
  font-size: .88rem;
  font-weight: 600;
  border: 2px solid transparent;
}

.level-tag.active {
  background: var(--navy);
  color: var(--gold);
  border-color: var(--navy);
}

.level-arrow {
  color: var(--gold);
  font-size: 1.1rem;
  font-weight: 700;
}

/* ── STEPS ── */
.steps {
  display: flex;
  align-items: flex-start;
  gap: 0;
}

.step {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 16px;
  padding: 0 12px;
}

.step-num {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: var(--navy);
  color: var(--gold);
  font-family: 'Playfair Display', serif;
  font-size: 1.4rem;
  font-weight: 900;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  box-shadow: 0 4px 20px rgba(15, 44, 87, .25);
}

.step-content h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 8px;
}

.step-content p {
  font-size: .88rem;
  color: var(--gray-600);
  line-height: 1.65;
}

.step-connector {
  flex: 0 0 40px;
  height: 2px;
  background: linear-gradient(to right, var(--navy), var(--gold));
  margin-top: 32px;
  opacity: .35;
}

/* ── PROMISE ── */
.section-promise {
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-mid) 100%);
}

.promise-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px;
}

.promise-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 14px;
  padding: 32px 20px;
  background: rgba(255, 255, 255, .07);
  border: 1px solid rgba(255, 255, 255, .12);
  border-radius: var(--radius-md);
  transition: var(--transition);
}

.promise-item:hover {
  background: rgba(255, 255, 255, .12);
  transform: translateY(-3px);
}

.promise-item span {
  font-size: 2.2rem;
}

.promise-item p {
  font-size: .9rem;
  color: rgba(255, 255, 255, .85);
  line-height: 1.65;
}

.promise-item strong {
  color: var(--gold-lt);
}

/* ── CONTACT ── */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.contact-card {
  border-radius: var(--radius-lg);
  padding: 40px 30px;
  text-align: center;
  box-shadow: var(--shadow-md);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  transition: var(--transition);
}

.contact-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.contact-phone {
  background: linear-gradient(135deg, var(--gold) 0%, #f5c842 100%);
  color: var(--navy);
}

.contact-zalo {
  background: linear-gradient(135deg, var(--zalo) 0%, #38a0ff 100%);
  color: var(--white);
}

.contact-address {
  background: var(--white);
  border: 2px solid var(--gray-100);
  color: var(--gray-800);
}

.contact-icon {
  font-size: 2.4rem;
}

.contact-card h3 {
  font-size: 1.1rem;
  font-weight: 800;
}

.contact-card p {
  font-size: .9rem;
  opacity: .85;
  line-height: 1.6;
}

.open-hours {
  display: inline-block;
  background: rgba(15, 44, 87, .07);
  border-radius: 50px;
  padding: 6px 16px;
  font-size: .82rem;
  font-weight: 600;
  color: var(--navy-mid);
}

/* ── FOOTER ── */
.footer {
  background: var(--gray-800);
  color: rgba(255, 255, 255, .75);
  padding: 48px 0 0;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  padding-bottom: 36px;
  border-bottom: 1px solid rgba(255, 255, 255, .08);
  flex-wrap: wrap;
}

.footer-brand {
  display: flex;
  align-items: flex-start;
  gap: 12px;
}

.footer-brand .logo-icon {
  font-size: 22px;
  color: var(--gold);
  margin-top: 3px;
}

.footer-brand strong {
  display: block;
  font-size: .95rem;
  color: var(--white);
  margin-bottom: 4px;
}

.footer-brand span {
  display: block;
  font-size: .82rem;
  line-height: 1.7;
}

.footer-links {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}

.footer-links a {
  font-size: .88rem;
  font-weight: 500;
  color: rgba(255, 255, 255, .65);
  transition: color var(--transition);
}

.footer-links a:hover {
  color: var(--gold);
}

.footer-copy {
  text-align: center;
  font-size: .8rem;
  color: rgba(255, 255, 255, .35);
  padding: 20px 24px;
}

/* ── ANIMATIONS ── */
.fade-up {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity .55s ease, transform .55s ease;
}

.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ══════════════════════════════════════════════════════════
   RESPONSIVE – MOBILE FIRST
   Breakpoints: 1024px (tablet) · 768px (mobile-lg) · 480px (mobile-sm)
   ══════════════════════════════════════════════════════════ */

/* ── Hamburger button (hidden on desktop) ── */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  border-radius: var(--radius-sm);
  transition: background var(--transition);
}

.hamburger:hover {
  background: var(--gray-100);
}

.hamburger span {
  display: block;
  width: 24px;
  height: 2.5px;
  background: var(--navy);
  border-radius: 2px;
  transition: transform .35s ease, opacity .25s ease;
}

.hamburger.open span:nth-child(1) {
  transform: translateY(7.5px) rotate(45deg);
}

.hamburger.open span:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}

.hamburger.open span:nth-child(3) {
  transform: translateY(-7.5px) rotate(-45deg);
}

/* Mobile drawer nav */
.mobile-nav {
  display: none;
  position: fixed;
  top: 70px;
  left: 0;
  right: 0;
  background: var(--white);
  border-bottom: 2px solid var(--gray-100);
  box-shadow: var(--shadow-md);
  z-index: 99;
  flex-direction: column;
  padding: 16px 24px 24px;
  gap: 4px;
  animation: slideDown .25s ease;
}

.mobile-nav.open {
  display: flex;
}

.mobile-nav a {
  padding: 13px 16px;
  font-size: 1rem;
  font-weight: 600;
  color: var(--gray-800);
  border-radius: var(--radius-sm);
  transition: background var(--transition), color var(--transition);
}

.mobile-nav a:hover {
  background: var(--sky);
  color: var(--navy);
}

.mobile-nav .btn-nav-mobile {
  margin-top: 8px;
  background: var(--navy);
  color: var(--white) !important;
  text-align: center;
  padding: 14px;
  border-radius: 50px;
  font-size: 1rem;
}

.mobile-nav .btn-zalo-mobile {
  background: var(--zalo);
  color: var(--white) !important;
  text-align: center;
  padding: 14px;
  border-radius: 50px;
  font-size: 1rem;
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }

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

/* ── Sticky bottom CTA bar (mobile only) ── */
.sticky-cta {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 98;
  background: var(--white);
  border-top: 1px solid var(--gray-100);
  box-shadow: 0 -4px 20px rgba(15, 44, 87, .12);
  padding: 10px 16px;
  gap: 10px;
  justify-content: center;
}

.sticky-cta a {
  flex: 1;
  max-width: 200px;
  text-align: center;
  padding: 13px 10px;
  border-radius: 50px;
  font-weight: 700;
  font-size: .92rem;
  font-family: 'Be Vietnam Pro', sans-serif;
}

.sticky-cta .s-phone {
  background: var(--gold);
  color: var(--navy);
}

.sticky-cta .s-zalo {
  background: var(--zalo);
  color: var(--white);
}

/* ── TABLET ── */
@media (max-width: 1024px) {
  .section {
    padding: 72px 0;
  }

  /* Grid adjustments */
  .subjects-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 18px;
  }

  .promise-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
  }

  .intro-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .intro-cards {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Steps – horizontal still but tighter */
  .step {
    padding: 0 8px;
  }

  .step-connector {
    flex: 0 0 24px;
  }
}

/* ── MOBILE LARGE (≤768px) ── */
@media (max-width: 768px) {

  /* Header */
  .nav {
    display: none;
  }

  .hamburger {
    display: flex;
  }

  /* Hero */
  .hero {
    padding: 100px 0 56px;
  }

  .hero-content {
    align-items: flex-start;
    gap: 18px;
  }

  .hero-badge {
    font-size: .78rem;
  }

  .hero-desc {
    font-size: .95rem;
  }

  .hero-cta {
    width: 100%;
    flex-direction: column;
    gap: 12px;
  }

  .hero-cta .btn {
    width: 100%;
    justify-content: center;
    padding: 15px;
    font-size: 1rem;
  }

  .hero-stats {
    flex-wrap: wrap;
    gap: 16px 24px;
    padding-top: 22px;
  }

  .stat-divider {
    display: none;
  }

  .stat-num {
    font-size: 1.7rem;
  }

  /* Section spacing */
  .section {
    padding: 60px 0;
  }

  .section-title {
    font-size: 1.65rem;
  }

  /* Intro */
  .intro-cards {
    grid-template-columns: 1fr 1fr;
    gap: 14px;
  }

  .value-card {
    padding: 18px 14px;
  }

  .value-icon {
    font-size: 1.5rem;
  }

  /* Subjects */
  .subjects-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 14px;
  }

  .subject-card {
    padding: 20px 14px;
  }

  .subject-icon {
    font-size: 1.8rem;
  }

  /* Levels row */
  .levels-row {
    gap: 8px;
  }

  .level-tag {
    font-size: .82rem;
    padding: 7px 16px;
  }

  /* Steps – vertical */
  .steps {
    flex-direction: column;
    gap: 0;
  }

  .step {
    flex-direction: row;
    text-align: left;
    align-items: flex-start;
    padding: 20px 0;
    border-bottom: 1px solid var(--gray-100);
    gap: 18px;
  }

  .step:last-child {
    border-bottom: none;
  }

  .step-num {
    flex-shrink: 0;
    width: 52px;
    height: 52px;
    font-size: 1.15rem;
  }

  .step-content h3 {
    font-size: .95rem;
  }

  .step-connector {
    display: none;
  }

  /* Promise */
  .promise-grid {
    grid-template-columns: 1fr 1fr;
    gap: 14px;
  }

  .promise-item {
    padding: 22px 14px;
    gap: 10px;
  }

  .promise-item span {
    font-size: 1.8rem;
  }

  .promise-item p {
    font-size: .84rem;
  }

  /* Contact */
  .contact-grid {
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .contact-card {
    padding: 30px 24px;
  }

  /* Footer */
  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 24px;
  }

  .footer-links {
    gap: 16px;
  }

  /* Show sticky CTA + add bottom padding to body */
  .sticky-cta {
    display: flex;
  }

  body {
    padding-bottom: 64px;
  }
}

/* ── MOBILE SMALL (≤480px) ── */
@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  /* Hero */
  .hero {
    padding: 90px 0 48px;
  }

  .hero-badge {
    display: none;
  }

  /* Keep hero clean on tiny screens */

  /* Intro cards – single column on very small */
  .intro-cards {
    grid-template-columns: 1fr;
  }

  /* Subjects – 2 col still fine */
  .subjects-grid {
    grid-template-columns: 1fr 1fr;
    gap: 12px;
  }

  .subject-card {
    padding: 16px 10px;
  }

  .subject-card p {
    display: none;
  }

  /* Show only icon+title to save space */

  /* Promise – single column */
  .promise-grid {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .promise-item {
    flex-direction: row;
    text-align: left;
    gap: 14px;
    padding: 16px;
  }

  /* Steps */
  .step-num {
    width: 44px;
    height: 44px;
    font-size: 1rem;
  }

  /* Levels */
  .levels-row {
    flex-direction: column;
    align-items: center;
    gap: 6px;
  }

  .level-arrow {
    transform: rotate(90deg);
    font-size: .9rem;
  }

  .level-tag {
    width: 100%;
    text-align: center;
  }

  /* Section */
  .section {
    padding: 48px 0;
  }

  .section-title {
    font-size: 1.45rem;
  }

  .section-desc {
    font-size: .9rem;
  }

  /* Contact */
  .contact-card {
    padding: 26px 18px;
  }

  .contact-icon {
    font-size: 2rem;
  }

  /* Footer */
  .footer-links {
    flex-direction: column;
    gap: 10px;
  }

  .footer-links a {
    padding: 6px 0;
  }

  /* Sticky CTA */
  .sticky-cta a {
    font-size: .85rem;
    padding: 12px 8px;
  }
}