/*
 * Shanghai Jiaoai Digital Technology - Official Website
 * Main Stylesheet
 * Color Scheme: Deep Tech Purple (#6B46C1) + Vibrant Teal (#00D9FF)
 */

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

:root {
  /* Primary Colors */
  --primary: #6B46C1;
  --primary-dark: #553399;
  --primary-light: #7C3AED;

  /* Secondary Colors */
  --secondary: #00D9FF;
  --secondary-dark: #00A8CC;
  --tertiary: #10B981;

  /* Neutral Colors */
  --text-dark: #1F2937;
  --text-gray: #6B7280;
  --text-light: #9CA3AF;
  --bg-light: #F9FAFB;
  --bg-white: #FFFFFF;
  --border-color: #E5E7EB;

  /* Spacing */
  --spacing-xs: 8px;
  --spacing-sm: 12px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  --spacing-3xl: 64px;

  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 10px 24px rgba(0, 0, 0, 0.12);
  --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.15);

  /* Transitions */
  --transition: all 0.3s ease;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Microsoft YaHei', 'Segoe UI', 'PingFang SC', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', Arial, sans-serif;
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text-dark);
  background-color: var(--bg-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
  color: var(--text-dark);
}

h1 {
  font-size: 2.5rem;
  margin-bottom: var(--spacing-lg);
}

h2 {
  font-size: 2rem;
  margin-bottom: var(--spacing-lg);
}

h3 {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-md);
}

h4 {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-md);
}

h5, h6 {
  font-size: 1rem;
  font-weight: 600;
}

p {
  margin-bottom: var(--spacing-md);
  color: var(--text-gray);
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: var(--primary-dark);
}

/* ============================================
   CONTAINER & LAYOUT
   ============================================ */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

.container-fluid {
  width: 100%;
}

/* ============================================
   HEADER & NAVIGATION
   ============================================ */
header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background-color: var(--primary);
  color: var(--bg-white);
  padding: var(--spacing-md) 0;
  z-index: 1000;
  box-shadow: var(--shadow-md);
}

header.scrolled {
  background-color: rgba(107, 70, 193, 0.95);
  backdrop-filter: blur(10px);
}

.nav-wrapper {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--bg-white);
}

.nav-logo img {
  height: 40px;
  width: auto;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: var(--spacing-xl);
  margin: 0;
  padding: 0;
}

.nav-menu a {
  color: var(--bg-white);
  font-size: 0.95rem;
  font-weight: 500;
  padding: var(--spacing-xs) var(--spacing-sm);
  position: relative;
  transition: var(--transition);
}

.nav-menu a:hover,
.nav-menu a.active {
  color: var(--secondary);
}

.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--secondary);
  transition: width 0.3s ease;
}

.nav-menu a:hover::after,
.nav-menu a.active::after {
  width: 100%;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--bg-white);
  font-size: 1.5rem;
  cursor: pointer;
}

/* ============================================
   BUTTONS & CTAS
   ============================================ */
.btn {
  display: inline-block;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  text-align: center;
  transition: var(--transition);
  cursor: pointer;
  border: none;
  text-decoration: none;
}

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

.btn-primary:hover {
  background-color: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background-color: var(--secondary);
  color: var(--text-dark);
}

.btn-secondary:hover {
  background-color: var(--secondary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-outline {
  background-color: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
}

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

.btn-lg {
  padding: var(--spacing-md) var(--spacing-2xl);
  font-size: 1.1rem;
}

.btn-sm {
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: 0.9rem;
}

/* ============================================
   CARDS & COMPONENTS
   ============================================ */
.card {
  background-color: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  border-left: 4px solid var(--primary);
  box-shadow: var(--shadow-md);
  transition: var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.card-accent-teal {
  border-left-color: var(--secondary);
}

.card-accent-green {
  border-left-color: var(--tertiary);
}

.card-image {
  width: 100%;
  height: 200px;
  background-color: var(--bg-light);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-md);
  object-fit: cover;
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  color: var(--text-dark);
}

.card-description {
  font-size: 0.95rem;
  color: var(--text-gray);
  margin-bottom: var(--spacing-md);
}

/* ============================================
   GRID SYSTEM
   ============================================ */
.grid {
  display: grid;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
}

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

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

.grid-cols-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-cols-4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.grid-auto-responsive {
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: var(--bg-white);
  padding: 120px 0 80px;
  text-align: center;
  position: relative;
  overflow: hidden;
  margin-top: 70px;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1200 400"><defs><pattern id="grid" width="40" height="40" patternUnits="userSpaceOnUse"><path d="M 40 0 L 0 0 0 40" fill="none" stroke="rgba(255,255,255,0.05)" stroke-width="1"/></pattern></defs><rect width="1200" height="400" fill="url(%23grid)"/></svg>');
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 10;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: var(--spacing-md);
  color: var(--bg-white);
}

.hero-subtitle {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-lg);
  color: rgba(255, 255, 255, 0.9);
}

.hero-cta {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* ============================================
   SECTION STYLING
   ============================================ */
section {
  padding: var(--spacing-3xl) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.section-header h2 {
  font-size: 2.5rem;
  margin-bottom: var(--spacing-md);
}

.section-header p {
  font-size: 1.1rem;
  color: var(--text-gray);
  max-width: 600px;
  margin: 0 auto;
}

.section-divider {
  width: 60px;
  height: 4px;
  background: linear-gradient(90deg, var(--primary) 0%, var(--secondary) 100%);
  margin: var(--spacing-md) auto var(--spacing-lg);
  border-radius: var(--radius-md);
}

section:nth-child(even) {
  background-color: var(--bg-light);
}

/* ============================================
   FEATURE GRID
   ============================================ */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

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

.feature-icon {
  width: 60px;
  height: 60px;
  margin: 0 auto var(--spacing-md);
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  color: var(--bg-white);
}

.feature-item h3 {
  margin-bottom: var(--spacing-sm);
}

.feature-item p {
  color: var(--text-gray);
}

/* ============================================
   TABS & ACCORDION
   ============================================ */
.tabs {
  display: flex;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
  border-bottom: 2px solid var(--border-color);
}

.tab-button {
  padding: var(--spacing-md) var(--spacing-lg);
  background: none;
  border: none;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-gray);
  cursor: pointer;
  position: relative;
  transition: var(--transition);
}

.tab-button.active {
  color: var(--primary);
}

.tab-button.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--primary);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* ============================================
   MODAL
   ============================================ */
.modal {
  display: none;
  position: fixed;
  z-index: 2000;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  animation: fadeIn 0.3s ease;
}

.modal-content {
  background-color: var(--bg-white);
  margin: 5% auto;
  padding: var(--spacing-lg);
  border-radius: var(--radius-lg);
  width: 90%;
  max-width: 600px;
  max-height: 80vh;
  overflow-y: auto;
  box-shadow: var(--shadow-xl);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-lg);
  border-bottom: 1px solid var(--border-color);
  padding-bottom: var(--spacing-md);
}

.modal-header h2 {
  margin: 0;
}

.modal-close {
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--text-gray);
  cursor: pointer;
  transition: var(--transition);
}

.modal-close:hover {
  color: var(--primary);
}

.modal.active {
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ============================================
   FOOTER
   ============================================ */
footer {
  background-color: var(--text-dark);
  color: var(--bg-white);
  padding: var(--spacing-3xl) 0 var(--spacing-lg);
  margin-top: var(--spacing-3xl);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}

.footer-section h4 {
  color: var(--bg-white);
  margin-bottom: var(--spacing-md);
}

.footer-section ul {
  list-style: none;
}

.footer-section ul li {
  margin-bottom: var(--spacing-sm);
}

.footer-section a {
  color: var(--bg-white);
  opacity: 0.8;
  transition: var(--transition);
}

.footer-section a:hover {
  color: var(--secondary);
  opacity: 1;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: var(--spacing-lg);
  text-align: center;
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.7);
}

.footer-icp {
  margin-top: var(--spacing-md);
  font-size: 0.85rem;
}

/* ============================================
   FILTER & SEARCH
   ============================================ */
.filter-controls {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  margin-bottom: var(--spacing-lg);
  flex-wrap: wrap;
}

.filter-btn {
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: var(--bg-light);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-gray);
  cursor: pointer;
  font-weight: 600;
  transition: var(--transition);
}

.filter-btn.active {
  background-color: var(--primary);
  color: var(--bg-white);
  border-color: var(--primary);
}

.search-box {
  width: 100%;
  max-width: 400px;
  margin: 0 auto var(--spacing-lg);
}

.search-box input {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: 1rem;
  transition: var(--transition);
}

.search-box input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(107, 70, 193, 0.1);
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */
@media (max-width: 768px) {
  h1 {
    font-size: 1.8rem;
  }

  h2 {
    font-size: 1.5rem;
  }

  h3 {
    font-size: 1.25rem;
  }

  .nav-wrapper {
    position: relative;
  }

  .nav-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: calc(-1 * var(--spacing-md));
    right: calc(-1 * var(--spacing-md));
    flex-direction: column;
    background-color: var(--primary);
    padding: var(--spacing-md);
    gap: 0;
    box-shadow: var(--shadow-lg);
    z-index: 1001;
  }

  .nav-menu.active {
    display: flex;
  }

  .nav-menu a {
    display: block;
    padding: var(--spacing-md);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--bg-white);
    text-align: center;
  }

  .nav-toggle {
    display: block;
    position: relative;
    width: 30px;
    height: 30px;
  }

  .nav-toggle i {
    display: none;
  }

  .nav-toggle::before,
  .nav-toggle::after {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
    height: 2px;
    background-color: var(--bg-white);
    transition: var(--transition);
  }

  .nav-toggle::before {
    top: 8px;
    box-shadow: 0 8px 0 var(--bg-white);
  }

  .nav-toggle::after {
    top: 24px;
  }

  .hero {
    padding: 100px 0 60px;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .hero-cta {
    flex-direction: column;
    align-items: center;
  }

  .hero-cta .btn {
    width: 100%;
  }

  section {
    padding: var(--spacing-2xl) 0;
  }

  .section-header {
    margin-bottom: var(--spacing-2xl);
  }

  .grid-cols-2,
  .grid-cols-3,
  .grid-cols-4 {
    grid-template-columns: repeat(1, minmax(0, 1fr));
  }

  .tabs {
    flex-wrap: wrap;
  }

  .filter-controls {
    flex-direction: column;
    align-items: center;
  }

  .filter-btn {
    width: 100%;
    max-width: 200px;
  }

  .modal-content {
    width: 95%;
    margin: 20% auto;
  }
}

@media (max-width: 480px) {
  :root {
    --spacing-lg: 16px;
    --spacing-xl: 20px;
  }

  h1 {
    font-size: 1.5rem;
  }

  h2 {
    font-size: 1.25rem;
  }

  .hero h1 {
    font-size: 1.5rem;
  }

  .hero-subtitle {
    font-size: 0.95rem;
  }

  .btn {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: 0.9rem;
  }

  .btn-lg {
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 1rem;
  }

  .container {
    padding: 0 var(--spacing-sm);
  }

  section {
    padding: var(--spacing-lg) 0;
  }

  .section-header h2 {
    font-size: 1.5rem;
  }
}

/* ============================================
   UTILITY CLASSES
   ============================================ */
.text-center {
  text-align: center;
}

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

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

.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }
.mt-5 { margin-top: var(--spacing-xl); }
.mt-6 { margin-top: var(--spacing-2xl); }

.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.mb-5 { margin-bottom: var(--spacing-xl); }
.mb-6 { margin-bottom: var(--spacing-2xl); }

.p-1 { padding: var(--spacing-xs); }
.p-2 { padding: var(--spacing-sm); }
.p-3 { padding: var(--spacing-md); }
.p-4 { padding: var(--spacing-lg); }
.p-5 { padding: var(--spacing-xl); }
.p-6 { padding: var(--spacing-2xl); }

.hidden {
  display: none !important;
}

.visible {
  display: block !important;
}

.opacity-50 {
  opacity: 0.5;
}

.opacity-75 {
  opacity: 0.75;
}

/* ============================================
   ANIMATIONS
   ============================================ */
@keyframes slideInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideInLeft {
  from {
    opacity: 0;
    transform: translateX(-30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideInRight {
  from {
    opacity: 0;
    transform: translateX(30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

.animate-on-scroll {
  opacity: 0;
  animation: slideInUp 0.6s ease forwards;
}

/* ============================================
   FORM STYLES
   ============================================ */
.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-group label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-weight: 600;
  color: var(--text-dark);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-family: inherit;
  transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(107, 70, 193, 0.1);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

/* ============================================
   BADGE & STATUS
   ============================================ */
.badge {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-md);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.badge-primary {
  background-color: var(--primary);
  color: var(--bg-white);
}

.badge-secondary {
  background-color: var(--secondary);
  color: var(--text-dark);
}

.badge-success {
  background-color: var(--tertiary);
  color: var(--bg-white);
}

.status-available {
  color: var(--tertiary);
  font-weight: 600;
}

.status-coming {
  color: var(--primary);
  font-weight: 600;
}

/* ============================================
   LOADING & PLACEHOLDER
   ============================================ */
.skeleton {
  background: linear-gradient(90deg, var(--bg-light) 0%, #f0f0f0 50%, var(--bg-light) 100%);
  background-size: 200% 100%;
  animation: loading 1.5s infinite;
  border-radius: var(--radius-md);
}

@keyframes loading {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}