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

:root {
  --brand: #1a2a5c;
  --brand-light: #2a3f7a;
  --brand-dark: #0f1a3a;
  --brand-gradient: linear-gradient(135deg, #1a2a5c, #2a3f7a);

  --blue: #004080;
  --blue-light: #2a6a9e;
  --orange: #e67e22;
  --orange-dark: #d35400;
  --green: #27ae60;
  --green-light: #2ecc71;
  --red: #c0392b;
  --red-light: #e74c3c;

  --grey: #f0f4f8;
  --grey-light: #f8fafc;
  --text: #1a2a3a;
  --text-light: #4a5b6e;
  --white: #ffffff;
  --shadow: 0 12px 48px rgba(0, 0, 0, 0.06);
  --shadow-hover: 0 24px 64px rgba(0, 0, 0, 0.10);
  --radius: 20px;
  --transition: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  --max-width: 1140px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Open Sans', sans-serif;
  background: var(--grey-light);
  color: var(--text);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 30px;
}

/* ============================================
   SCROLLBAR
   ============================================ */
::-webkit-scrollbar {
  width: 8px;
}
::-webkit-scrollbar-track {
  background: var(--grey);
}
::-webkit-scrollbar-thumb {
  background: var(--brand);
  border-radius: 10px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--brand-dark);
}

/* ============================================
   LANGUAGE TOGGLE - 固定在顶部
   ============================================ */
.lang-toggle {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
  padding: 8px 30px;
  background: var(--white);
  border-bottom: 1px solid rgba(0, 0, 0, 0.04);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.lang-btn {
  background: transparent;
  border: 1.5px solid #e0e6ed;
  padding: 5px 18px;
  border-radius: 30px;
  font-weight: 600;
  font-size: 0.78rem;
  color: #5a6b7e;
  cursor: pointer;
  transition: var(--transition);
}

.lang-btn.active {
  background: var(--brand);
  border-color: var(--brand);
  color: var(--white);
}

.lang-btn i {
  margin-right: 5px;
}

.lang-btn:hover:not(.active) {
  border-color: var(--brand);
  color: var(--brand);
}

/* ============================================
   HEADER
   ============================================ */
.main-header {
  background: var(--brand-gradient);
  color: var(--white);
  padding: 24px 0;
  position: relative;
  overflow: hidden;
}

.main-header::after {
  content: '';
  position: absolute;
  top: -40%;
  right: -10%;
  width: 55%;
  height: 180%;
  background: rgba(255, 255, 255, 0.03);
  transform: rotate(18deg);
  pointer-events: none;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 28px;
  position: relative;
  z-index: 1;
}

.header-logo-img {
  width: 68px;
  height: 68px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid rgba(255, 255, 255, 0.2);
  background: var(--white);
  padding: 4px;
  transition: var(--transition);
}

.header-logo-img:hover {
  transform: scale(1.06);
  border-color: rgba(255, 255, 255, 0.5);
}

.header-title {
  text-align: center;
}

.header-title h1 {
  font-family: 'Montserrat', sans-serif;
  font-weight: 800;
  font-size: 2.2rem;
  letter-spacing: -0.5px;
}

.header-title .subhead {
  font-weight: 300;
  font-size: 1rem;
  opacity: 0.85;
  margin-top: 4px;
  letter-spacing: 2px;
}

.header-title .subhead-zh {
  font-weight: 300;
  font-size: 0.88rem;
  opacity: 0.6;
  margin-top: 2px;
  letter-spacing: 1px;
}

/* ============================================
   NAVIGATION - 跟随滚动
   ============================================ */
.main-nav {
  background: var(--white);
  box-shadow: 0 2px 16px rgba(0, 0, 0, 0.04);
  position: sticky;
  top: 44px;  /* 语言切换栏高度 */
  z-index: 999;
  padding: 0 30px;
  transition: box-shadow 0.3s ease;
}

.main-nav.scrolled {
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.08);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 62px;
}

.nav-brand {
  font-weight: 700;
  color: var(--brand);
  font-size: 1.05rem;
  letter-spacing: 0.5px;
}

.nav-brand i {
  margin-right: 8px;
}

.nav-links {
  display: flex;
  gap: 30px;
  align-items: center;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-light);
  font-weight: 500;
  font-size: 0.88rem;
  padding: 6px 0;
  border-bottom: 2.5px solid transparent;
  transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--brand);
  border-bottom-color: var(--brand);
}

.nav-links a i {
  margin-right: 6px;
}

/* ============================================
   HERO
   ============================================ */
.hero {
  padding: 70px 0 60px;
  background: linear-gradient(135deg, #f0f4fa 0%, var(--grey-light) 100%);
  position: relative;
}

.hero::before {
  content: '';
  position: absolute;
  top: -20%;
  left: -10%;
  width: 60%;
  height: 140%;
  background: radial-gradient(circle, rgba(26, 42, 92, 0.04) 0%, transparent 70%);
  pointer-events: none;
}

.hero-grid {
  display: flex;
  align-items: center;
  gap: 50px;
  position: relative;
  z-index: 1;
}

.hero-text {
  flex: 1.2;
}

.hero-tag {
  display: inline-block;
  background: var(--brand);
  color: var(--white);
  padding: 4px 20px;
  border-radius: 30px;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  margin-bottom: 18px;
  box-shadow: 0 4px 16px rgba(26, 42, 92, 0.2);
}

.hero-text h2 {
  font-family: 'Montserrat', sans-serif;
  font-size: 3.2rem;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 16px;
}

.hero-text h2 .highlight {
  color: var(--brand);
  position: relative;
}

.hero-text h2 .highlight::after {
  content: '';
  position: absolute;
  bottom: 6px;
  left: 0;
  right: 0;
  height: 10px;
  background: rgba(26, 42, 92, 0.10);
  border-radius: 4px;
}

.hero-text p {
  font-size: 1.1rem;
  color: var(--text-light);
  max-width: 520px;
  line-height: 1.8;
  margin-bottom: 28px;
}

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

.btn-primary,
.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 34px;
  border-radius: 50px;
  font-weight: 600;
  font-size: 0.92rem;
  text-decoration: none;
  transition: var(--transition);
}

.btn-primary {
  background: var(--brand-gradient);
  color: var(--white);
  box-shadow: 0 6px 20px rgba(26, 42, 92, 0.25);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 36px rgba(26, 42, 92, 0.30);
}

.btn-secondary {
  background: var(--white);
  color: var(--brand);
  border: 2px solid var(--brand);
}

.btn-secondary:hover {
  background: var(--brand);
  color: var(--white);
  transform: translateY(-3px);
}

.hero-image {
  flex: 0.8;
  text-align: center;
}

.hero-image-wrapper {
  position: relative;
  display: inline-block;
}

.hero-logo-img {
  width: 220px;
  height: 220px;
  border-radius: 50%;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.10);
  background: var(--white);
  padding: 10px;
  object-fit: cover;
  border: 4px solid rgba(255, 255, 255, 0.1);
  transition: var(--transition);
}

.hero-logo-img:hover {
  transform: scale(1.02);
}

.floating-badge {
  position: absolute;
  bottom: -6px;
  right: -16px;
  background: var(--white);
  padding: 8px 18px;
  border-radius: 30px;
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 0.82rem;
  color: var(--brand);
  animation: floatBadge 3s ease-in-out infinite;
}

@keyframes floatBadge {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-6px); }
}

.floating-badge i {
  color: #f1c40f;
  font-size: 1rem;
}

/* ============================================
   SECTION LABEL
   ============================================ */
.section-label {
  text-align: center;
  margin-bottom: 44px;
}

.label-tag {
  display: inline-block;
  background: rgba(26, 42, 92, 0.08);
  color: var(--brand);
  padding: 4px 20px;
  border-radius: 30px;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.section-label h2 {
  font-family: 'Montserrat', sans-serif;
  font-size: 2.4rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
}

.section-label p {
  color: var(--text-light);
  font-size: 1.02rem;
}

/* ============================================
   ABOUT
   ============================================ */
#presentation {
  padding: 60px 0 50px;
}

.about-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 48px 52px;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.about-card:hover {
  box-shadow: var(--shadow-hover);
}

.about-grid {
  display: flex;
  flex-direction: column;
  gap: 30px;
}

.about-text p {
  font-size: 1.02rem;
  line-height: 1.9;
  color: var(--text-light);
  margin-bottom: 14px;
}

.about-text p:last-of-type {
  margin-bottom: 0;
}

.about-text strong {
  color: var(--text);
}

.about-values-stats {
  display: flex;
  flex-direction: column;
  gap: 24px;
  padding-top: 24px;
  border-top: 1px solid #e8edf5;
}

.about-values {
  display: flex;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.value-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--grey);
  padding: 6px 20px;
  border-radius: 30px;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text);
  transition: var(--transition);
}

.value-tag:hover {
  background: var(--brand);
  color: var(--white);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(26, 42, 92, 0.20);
}

.value-tag:hover i {
  color: var(--white);
}

.value-tag i {
  color: var(--brand);
  font-size: 0.88rem;
  transition: var(--transition);
}

.about-stats {
  display: flex;
  justify-content: center;
  gap: 50px;
  padding-top: 24px;
  border-top: 1px solid #e8edf5;
}

.stat-item {
  text-align: center;
  min-width: 70px;
}

.stat-number {
  font-family: 'Montserrat', sans-serif;
  font-size: 2.2rem;
  font-weight: 800;
  color: var(--brand);
  display: block;
  line-height: 1.2;
}

.stat-label {
  font-size: 0.82rem;
  color: var(--text-light);
  margin-top: 4px;
}

/* ============================================
   PILIERS
   ============================================ */
#piliers {
  padding: 50px 0 70px;
}

.cards-grid {
  display: grid;
  gap: 28px;
}

.cards-grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

.card-pilier {
  background: var(--white);
  border-radius: var(--radius);
  padding: 36px 28px 30px;
  box-shadow: var(--shadow);
  text-align: center;
  transition: var(--transition);
  border-bottom: 5px solid transparent;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.card-pilier:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-hover);
}

.card-icon {
  width: 70px;
  height: 70px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  font-size: 2rem;
  color: var(--white);
  transition: var(--transition);
  flex-shrink: 0;
}

.card-pilier:hover .card-icon {
  transform: scale(1.04) rotate(-4deg);
}

.card-icon.blue { background: var(--blue); }
.card-icon.orange { background: var(--orange); }
.card-icon.green { background: var(--green); }
.card-icon.red { background: var(--red); }

.card-pilier h3 {
  font-family: 'Montserrat', sans-serif;
  font-size: 1.3rem;
  margin-bottom: 8px;
}

.card-pilier p {
  color: var(--text-light);
  font-size: 0.92rem;
  line-height: 1.7;
  margin-bottom: 20px;
  flex: 1;
}

.card-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 10px 28px;
  border-radius: 50px;
  font-weight: 600;
  font-size: 0.88rem;
  text-decoration: none;
  transition: var(--transition);
  color: var(--white);
  width: 100%;
  max-width: 200px;
  margin-top: auto;
}

.card-btn.blue-btn { background: var(--blue); }
.card-btn.orange-btn { background: var(--orange); }
.card-btn.green-btn { background: var(--green); }
.card-btn.red-btn { background: var(--red); }

.card-btn:hover {
  transform: translateY(-2px);
  filter: brightness(0.92);
}

.card-btn:hover i {
  transform: translateX(4px);
}

.card-btn i {
  transition: var(--transition);
}

.card-pilier.blue-card { border-bottom-color: var(--blue); }
.card-pilier.blue-card:hover { border-bottom-color: var(--blue-light); }

.card-pilier.orange-card { border-bottom-color: var(--orange); }
.card-pilier.orange-card:hover { border-bottom-color: var(--orange-dark); }

.card-pilier.green-card { border-bottom-color: var(--green); }
.card-pilier.green-card:hover { border-bottom-color: var(--green-light); }

.card-pilier.red-card { border-bottom-color: var(--red); }
.card-pilier.red-card:hover { border-bottom-color: var(--red-light); }

/* ============================================
   FOOTER
   ============================================ */
.main-footer {
  background: #0a1628;
  color: #c8d6e5;
  padding: 44px 0 24px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 44px;
}

.footer-col h4 {
  color: var(--white);
  font-family: 'Montserrat', sans-serif;
  font-size: 0.98rem;
  margin-bottom: 14px;
}

.footer-col p,
.footer-col a {
  color: #9aadc8;
  font-size: 0.9rem;
  text-decoration: none;
  display: block;
  margin-bottom: 6px;
  transition: var(--transition);
}

.footer-col a:hover {
  color: var(--white);
}

.footer-col i {
  width: 22px;
  color: var(--orange);
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 6px;
}

.contact-item i {
  width: 22px;
  color: var(--orange);
}

.contact-item a {
  display: inline;
  color: #9aadc8;
}

.contact-item a:hover {
  color: var(--white);
}

.footer-bottom {
  border-top: 1px solid #1a2a40;
  margin-top: 28px;
  padding-top: 18px;
  text-align: center;
  font-size: 0.82rem;
  color: #6a7f9a;
}

.footer-bottom .sep {
  margin: 0 12px;
  color: #2a3a50;
}

/* ============================================
   MODAL
   ============================================ */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.55);
  backdrop-filter: blur(8px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 9999;
}

.modal-overlay.show {
  display: flex;
}

.modal-container {
  background: var(--white);
  border-radius: var(--radius);
  padding: 42px 38px 34px;
  max-width: 430px;
  width: 90%;
  text-align: center;
  animation: modalFadeIn 0.3s ease;
}

@keyframes modalFadeIn {
  from { opacity: 0; transform: scale(0.95) translateY(20px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}

.modal-icon {
  width: 72px;
  height: 72px;
  background: var(--grey);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  font-size: 2.4rem;
  color: var(--brand);
}

.modal-container h3 {
  font-family: 'Montserrat', sans-serif;
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
}

.modal-container p {
  color: var(--text-light);
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 20px;
}

.modal-btn {
  background: var(--brand-gradient);
  color: var(--white);
  border: none;
  padding: 10px 32px;
  border-radius: 50px;
  font-weight: 600;
  font-size: 0.88rem;
  cursor: pointer;
  transition: var(--transition);
}

.modal-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(26, 42, 92, 0.25);
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 1024px) {
  .cards-grid-4 {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
  }
}

@media (max-width: 992px) {
  .hero-grid {
    flex-direction: column;
    text-align: center;
    gap: 35px;
  }
  .hero-text p {
    max-width: 100%;
  }
  .hero-buttons {
    justify-content: center;
  }
  .hero-text h2 {
    font-size: 2.4rem;
  }
  .hero-logo-img {
    width: 180px;
    height: 180px;
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
  .about-stats {
    gap: 35px;
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 20px;
  }
  .lang-toggle {
    padding: 6px 20px;
  }
  .main-nav {
    top: 42px; /* 移动端语言切换栏高度略小 */
  }
  .header-inner {
    flex-direction: column;
    gap: 10px;
  }
  .header-title h1 {
    font-size: 1.6rem;
  }
  .main-nav {
    padding: 0 20px;
  }
  .nav-inner {
    flex-direction: column;
    padding: 10px 0;
    gap: 6px;
  }
  .nav-links {
    gap: 16px;
    flex-wrap: wrap;
    justify-content: center;
  }
  .nav-links a {
    font-size: 0.8rem;
  }
  .hero {
    padding: 40px 0 30px;
  }
  .hero-text h2 {
    font-size: 2rem;
  }
  .hero-text p {
    font-size: 0.98rem;
  }
  .hero-logo-img {
    width: 150px;
    height: 150px;
  }
  .floating-badge {
    padding: 6px 14px;
    font-size: 0.72rem;
    bottom: -4px;
    right: -12px;
  }
  .section-label h2 {
    font-size: 1.8rem;
  }
  .about-card {
    padding: 28px 22px;
  }
  .about-stats {
    gap: 24px;
    flex-wrap: wrap;
  }
  .about-values {
    justify-content: center;
  }
  .cards-grid-4 {
    grid-template-columns: 1fr;
    max-width: 400px;
    margin: 0 auto;
  }
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }
  .footer-bottom .sep {
    display: none;
  }
  .modal-container {
    padding: 30px 22px 26px;
  }
  .modal-icon {
    width: 60px;
    height: 60px;
    font-size: 2rem;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }
  .lang-btn {
    font-size: 0.68rem;
    padding: 4px 12px;
  }
  .main-nav {
    top: 38px;
  }
  .header-title h1 {
    font-size: 1.3rem;
  }
  .hero-text h2 {
    font-size: 1.6rem;
  }
  .btn-primary,
  .btn-secondary {
    padding: 10px 20px;
    font-size: 0.82rem;
    width: 100%;
    justify-content: center;
  }
  .hero-buttons {
    width: 100%;
  }
  .hero-logo-img {
    width: 120px;
    height: 120px;
  }
  .about-card {
    padding: 20px 16px;
  }
  .about-text p {
    font-size: 0.92rem;
  }
  .card-pilier {
    padding: 24px 18px 22px;
  }
  .stat-number {
    font-size: 1.8rem;
  }
  .about-stats {
    gap: 16px;
  }
  .modal-container {
    padding: 24px 16px 20px;
  }
  .modal-icon {
    width: 52px;
    height: 52px;
    font-size: 1.6rem;
  }
  .modal-container h3 {
    font-size: 1.15rem;
  }
}