/* ============================================
   秦岭科学（香港）研究院 — Antigravity Style
   ============================================ */

:root {
  --primary: #0b4f3b;
  --primary-light: #167a5e;
  --accent: #20bf6b;
  --secondary: #f7b731;
  --text-main: #2d3436;
  --text-muted: #636e72;
  --bg-main: #ffffff;
  --bg-light: #f8f9fa;
  --bg-dark: #1e272e;
  --font-sans: 'Noto Sans SC', 'Inter', -apple-system, sans-serif;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.05);
  --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
  --shadow-lg: 0 20px 40px rgba(0,0,0,0.12);
  --radius-md: 12px;
  --radius-lg: 20px;
  --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-sans);
  color: var(--text-main);
  background: var(--bg-main);
  line-height: 1.6;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  color: var(--bg-dark);
}

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

.text-gradient {
  background: linear-gradient(135deg, var(--accent), var(--primary-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.lead {
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--primary);
  margin-bottom: 1.5rem;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.section { padding: 6rem 0; }
.bg-light { background: var(--bg-light); }

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.85rem 2rem;
  font-size: 1rem;
  font-weight: 600;
  font-family: var(--font-sans);
  border-radius: 50px;
  text-decoration: none;
  transition: var(--transition);
  cursor: pointer;
  border: 2px solid transparent;
}

.btn-primary {
  background: var(--primary);
  color: white;
  box-shadow: 0 4px 14px rgba(11, 79, 59, 0.3);
}

.btn-primary:hover {
  background: var(--primary-light);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(11, 79, 59, 0.4);
}

.btn-outline {
  background: transparent;
  color: white;
  border-color: rgba(255,255,255,0.5);
}

.btn-outline:hover {
  background: white;
  color: var(--primary);
}

.btn-outline-light {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 1rem;
  padding: 0.6rem 1.4rem;
  border-radius: 50px;
  font-size: 0.9rem;
  font-weight: 600;
  color: white;
  border: 1.5px solid rgba(255,255,255,0.5);
  transition: var(--transition);
}

.btn-outline-light:hover {
  background: rgba(255,255,255,0.15);
}

/* --- Section Header --- */
.section-header { margin-bottom: 4rem; }

.section-title {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 4px;
  background: var(--accent);
  border-radius: 2px;
}

.section-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 1.5rem auto 0;
}

/* ========================
   Navigation
   ======================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  padding: 1rem 0;
  z-index: 1000;
  transition: var(--transition);
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
}

.navbar.scrolled {
  padding: 0.7rem 0;
  box-shadow: 0 8px 24px rgba(0,0,0,0.1);
  background: rgba(255,255,255,0.98);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 2rem;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-text {
  display: flex;
  flex-direction: column;
}

.logo-cn {
  font-size: 1.3rem;
  font-weight: 900;
  color: var(--primary);
  letter-spacing: 1px;
  line-height: 1.3;
}

.logo-en {
  font-size: 0.65rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  line-height: 1.3;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 1.8rem;
}

.nav-link {
  color: var(--text-main);
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: var(--transition);
}

.nav-link:hover { color: var(--primary); }
.nav-link:hover::after { width: 100%; }

.nav-link-btn {
  background: var(--primary);
  color: white !important;
  padding: 0.5rem 1.4rem;
  border-radius: 50px;
  font-size: 0.9rem;
}

.nav-link-btn::after { display: none; }

.nav-link-btn:hover {
  background: var(--primary-light);
  color: white !important;
}

.lang-toggle {
  background: none;
  border: 1px solid var(--text-muted);
  border-radius: 4px;
  padding: 0.2rem 0.6rem;
  cursor: pointer;
  font-family: inherit;
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--text-muted);
  transition: var(--transition);
}

.lang-toggle:hover {
  color: var(--primary);
  border-color: var(--primary);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 25px;
  height: 3px;
  background: var(--text-main);
  transition: var(--transition);
}

.nav-toggle.active span:nth-child(1) { transform: translateY(8px) rotate(45deg); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: translateY(-8px) rotate(-45deg); }

/* ========================
   Hero
   ======================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8rem 2rem 4rem;
  background: url('https://images.unsplash.com/photo-1549558549-415fe4c37b60?ixlib=rb-4.0.3&auto=format&fit=crop&w=2000&q=80') center/cover no-repeat;
  color: white;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to right, rgba(11, 79, 59, 0.88), rgba(30, 39, 46, 0.6));
  z-index: 1;
}

.hero-content {
  position: relative;
  z-index: 2;
  text-align: center;
  max-width: 900px;
}

.hero-title {
  font-size: clamp(2.5rem, 5vw, 4rem);
  color: white;
  margin-bottom: 1.5rem;
  letter-spacing: 2px;
  opacity: 0;
  transform: translateY(30px);
  animation: fadeUp 1s ease forwards;
}

.hero-subtitle {
  font-size: 1.3rem;
  font-weight: 300;
  margin-bottom: 3rem;
  opacity: 0;
  transform: translateY(30px);
  animation: fadeUp 1s ease 0.3s forwards;
}

.hero-actions {
  display: flex;
  gap: 1.5rem;
  justify-content: center;
  margin-bottom: 4rem;
  opacity: 0;
  transform: translateY(30px);
  animation: fadeUp 1s ease 0.6s forwards;
}

/* Hero Stats */
.hero-stats {
  display: flex;
  justify-content: center;
  gap: clamp(2rem, 5vw, 4rem);
  opacity: 0;
  animation: fadeIn 1.5s ease 1s forwards;
}

.stat-item { text-align: center; }

.stat-number {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  color: var(--secondary);
  line-height: 1;
  margin-bottom: 0.5rem;
}

.stat-label {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: rgba(255,255,255,0.8);
}

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

@keyframes fadeIn {
  to { opacity: 1; }
}

/* ========================
   About
   ======================== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: start;
}

.about-text p {
  margin-bottom: 1.5rem;
  color: var(--text-muted);
}

.about-cards {
  display: grid;
  gap: 1.5rem;
}

.about-card {
  background: white;
  border-radius: var(--radius-md);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  border-left: 4px solid var(--accent);
}

.about-card:hover {
  transform: translateX(10px);
  box-shadow: var(--shadow-md);
}

.card-icon {
  font-size: 2rem;
  margin-bottom: 0.5rem;
}

.about-card h3 {
  margin-bottom: 0.5rem;
  font-size: 1.2rem;
}

.about-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin: 0;
}

/* ========================
   Research
   ======================== */
.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.research-card {
  background: white;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.research-card:hover {
  transform: translateY(-10px);
  box-shadow: var(--shadow-lg);
}

.research-card-img {
  height: 200px;
  background-size: cover;
  background-position: center;
  position: relative;
  overflow: hidden;
}

.research-card-img::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(0,0,0,0.5), transparent);
}

.research-card-content {
  padding: 1.5rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.research-card h3 {
  font-size: 1.3rem;
  margin-bottom: 0.25rem;
}

.research-en {
  font-size: 0.8rem;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 1rem;
  text-transform: uppercase;
}

.research-desc {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
  flex: 1;
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.tags li {
  font-size: 0.8rem;
  background: var(--bg-light);
  padding: 0.2rem 0.8rem;
  border-radius: 20px;
  color: var(--text-main);
  border: 1px solid #eee;
}

/* ========================
   Projects
   ======================== */
.projects-list {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  max-width: 900px;
  margin: 0 auto;
}

.project-item {
  display: flex;
  gap: 2rem;
  background: white;
  padding: 2rem;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  border: 1px solid rgba(0,0,0,0.02);
}

.project-item:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--accent);
}

.project-number {
  font-size: 3rem;
  font-weight: 900;
  color: rgba(11, 79, 59, 0.1);
  line-height: 1;
  flex-shrink: 0;
}

.project-info { flex: 1; }

.project-info h3 {
  font-size: 1.4rem;
  margin-bottom: 1rem;
  color: var(--primary);
}

.project-info p {
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
}

.read-more {
  color: var(--accent);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.read-more span { transition: var(--transition); }
.read-more:hover span { transform: translateX(5px); }

/* ========================
   Team
   ======================== */
.team-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

.team-card {
  text-align: center;
  padding: 2rem;
  background: white;
  border-radius: var(--radius-lg);
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

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

.team-avatar {
  width: 100px;
  height: 100px;
  margin: 0 auto 1.5rem;
}

.avatar-placeholder {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--primary);
  background: rgba(11, 79, 59, 0.1);
}

.team-card h3 {
  font-size: 1.2rem;
  margin-bottom: 0.3rem;
}

.team-title {
  color: var(--accent);
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 0.3rem;
}

.team-field {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.team-bio {
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* ========================
   News
   ======================== */
.news-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.news-card {
  background: white;
  padding: 2rem;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  border-left: 4px solid var(--text-muted);
}

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

.news-date {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
  font-family: monospace;
}

.news-card h3 {
  font-size: 1.2rem;
  margin-bottom: 1rem;
}

.news-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
}

.highlight-card {
  border-left-color: var(--primary);
  background: var(--primary);
  color: white;
}

.highlight-card h3,
.highlight-card p { color: white; }

.news-tag-badge {
  background: rgba(255,255,255,0.2);
  display: inline-block;
  padding: 0.3rem 0.8rem;
  border-radius: 20px;
  font-size: 0.8rem;
  margin-bottom: 1rem;
}

/* ========================
   Footer
   ======================== */
.footer {
  background: var(--bg-dark);
  color: white;
  padding: 5rem 0 2rem;
}

.footer-content {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: 4rem;
  margin-bottom: 4rem;
}

.footer-info h2 {
  color: white;
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.footer-slogan {
  color: var(--accent);
  margin-bottom: 2rem;
  font-weight: 500;
}

.contact-details p {
  margin-bottom: 0.8rem;
  color: rgba(255,255,255,0.7);
  font-size: 0.95rem;
}

.contact-details a {
  color: rgba(255,255,255,0.7);
}

.contact-details a:hover { color: var(--accent); }

.footer-links-wrap {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.link-col {
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
}

.link-col h4 {
  color: white;
  margin-bottom: 0.8rem;
  font-size: 1.1rem;
}

.link-col a {
  color: rgba(255,255,255,0.6);
  transition: var(--transition);
  font-size: 0.95rem;
}

.link-col a:hover {
  color: var(--accent);
  padding-left: 5px;
}

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid rgba(255,255,255,0.1);
  color: rgba(255,255,255,0.4);
  font-size: 0.85rem;
}

/* ========================
   Fade-in Animation
   ======================== */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease-out, transform 0.7s ease-out;
}

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

/* ========================
   Responsive
   ======================== */
@media (max-width: 900px) {
  .nav-menu {
    position: fixed;
    top: 70px;
    left: 0;
    right: 0;
    background: rgba(255,255,255,0.98);
    backdrop-filter: blur(12px);
    flex-direction: column;
    padding: 2rem;
    gap: 0.8rem;
    box-shadow: var(--shadow-md);
    transform: translateY(-120%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.4s, opacity 0.4s;
  }

  .nav-menu.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }

  .nav-toggle { display: flex; }

  .about-grid { grid-template-columns: 1fr; gap: 2rem; }

  .footer-content {
    grid-template-columns: 1fr;
    gap: 3rem;
  }

  .project-item {
    flex-direction: column;
    gap: 1rem;
  }

  .hero-actions {
    flex-direction: column;
    align-items: center;
    gap: 1rem;
  }

  .hero-stats {
    flex-wrap: wrap;
    gap: 1.5rem;
  }
}

@media (max-width: 480px) {
  .logo-en { display: none; }
  .hero-title { font-size: 2rem; }
}