/* ============================================================
   滁州讯星人工智能科技有限公司 - 企业官网全局样式
   Design: 简约大气 / Clean & Professional
   ============================================================ */

/* --- CSS Variables --- */
:root {
  --primary: #1a56db;
  --primary-dark: #1e40af;
  --primary-light: #3b82f6;
  --primary-bg: #eff6ff;
  --accent: #06b6d4;
  --text: #1e293b;
  --text-secondary: #64748b;
  --text-light: #94a3b8;
  --bg: #ffffff;
  --bg-alt: #f8fafc;
  --bg-dark: #0f172a;
  --border: #e2e8f0;
  --border-light: #f1f5f9;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
  --shadow-xl: 0 20px 25px rgba(0,0,0,0.1), 0 10px 10px rgba(0,0,0,0.04);
  --radius: 12px;
  --radius-sm: 8px;
  --radius-lg: 16px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --max-width: 1200px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
  overflow-x: hidden;
}

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

ul, ol { list-style: none; }

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

button {
  cursor: pointer;
  border: none;
  font-family: inherit;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 100px 0;
}

.section-label {
  display: inline-block;
  font-size: 14px;
  font-weight: 600;
  color: var(--primary);
  background: var(--primary-bg);
  padding: 6px 16px;
  border-radius: 20px;
  margin-bottom: 16px;
  letter-spacing: 0.5px;
}

.section-title {
  font-size: 40px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 16px;
  line-height: 1.3;
}

.section-desc {
  font-size: 18px;
  color: var(--text-secondary);
  max-width: 600px;
  line-height: 1.8;
}

/* --- Navbar --- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid transparent;
  transition: all var(--transition);
}

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

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
}

.nav-logo .logo-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -1px;
}

.nav-logo .logo-wrap {
  position: relative;
  width: 40px;
  height: 40px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.nav-logo .logo-img {
  max-height: 40px;
  width: auto;
  max-width: 160px;
  object-fit: contain;
  border-radius: 8px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-links a {
  padding: 8px 20px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary);
  background: var(--primary-bg);
}

.nav-cta {
  background: var(--primary) !important;
  color: #fff !important;
  padding: 10px 24px !important;
  border-radius: 8px !important;
}

.nav-cta:hover {
  background: var(--primary-dark) !important;
  color: #fff !important;
}

.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: all var(--transition);
}

/* --- Hero --- */
.hero {
  padding: 160px 0 100px;
  background: linear-gradient(180deg, #f0f5ff 0%, #ffffff 100%);
  overflow: hidden;
}

.hero .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: center;
}

.hero-content h1 {
  font-size: 52px;
  font-weight: 800;
  line-height: 1.2;
  color: var(--text);
  margin-bottom: 24px;
}

.hero-content h1 .highlight {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-content p {
  font-size: 18px;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 40px;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 10px;
  font-size: 16px;
  font-weight: 600;
  transition: all var(--transition);
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 4px 14px rgba(26, 86, 219, 0.35);
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(26, 86, 219, 0.45);
}

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

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

.hero-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-card {
  background: #fff;
  border-radius: var(--radius-lg);
  padding: 48px;
  box-shadow: var(--shadow-xl);
  position: relative;
}

.hero-card::before {
  content: '';
  position: absolute;
  inset: -2px;
  border-radius: 18px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  z-index: -1;
  opacity: 0.15;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

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

.stat-number {
  font-size: 36px;
  font-weight: 800;
  color: var(--primary);
  display: block;
}

.stat-label {
  font-size: 14px;
  color: var(--text-secondary);
  margin-top: 4px;
}

/* --- Services Grid --- */
.services-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 60px;
}

.service-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px;
  transition: all var(--transition);
  cursor: default;
}

.service-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.service-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 26px;
  margin-bottom: 20px;
}

.service-icon.blue { background: #eff6ff; color: var(--primary); }
.service-icon.cyan { background: #ecfeff; color: var(--accent); }
.service-icon.indigo { background: #eef2ff; color: #6366f1; }
.service-icon.green { background: #ecfdf5; color: #10b981; }
.service-icon.amber { background: #fffbeb; color: #f59e0b; }
.service-icon.rose { background: #fff1f2; color: #f43f5e; }

.service-card h3 {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text);
}

.service-card p {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* --- About Page --- */
.page-header {
  padding: 160px 0 80px;
  background: linear-gradient(180deg, #f0f5ff 0%, #ffffff 100%);
  text-align: center;
}

.page-header h1 {
  font-size: 44px;
  font-weight: 800;
  margin-bottom: 16px;
}

.page-header p {
  font-size: 18px;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

.about-content {
  padding: 0 0 100px;
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: center;
}

.about-image {
  background: linear-gradient(135deg, var(--primary-bg), #f0f9ff);
  border-radius: var(--radius-lg);
  aspect-ratio: 4/3;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.about-image .placeholder {
  font-size: 80px;
  opacity: 0.3;
}

.about-text h2 {
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 20px;
}

.about-text p {
  font-size: 16px;
  color: var(--text-secondary);
  line-height: 1.9;
  margin-bottom: 16px;
}

.about-features {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 32px;
}

.about-feature {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px;
  background: var(--bg-alt);
  border-radius: var(--radius-sm);
}

.about-feature .check {
  width: 24px;
  height: 24px;
  background: var(--primary-bg);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  font-size: 14px;
  flex-shrink: 0;
}

.about-feature span {
  font-size: 14px;
  font-weight: 500;
  color: var(--text);
}

/* --- Timeline --- */
.timeline-section {
  padding: 0 0 100px;
}

.timeline {
  position: relative;
  max-width: 800px;
  margin: 60px auto 0;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  width: 2px;
  height: 100%;
  background: var(--border);
}

.timeline-item {
  display: flex;
  align-items: flex-start;
  margin-bottom: 48px;
  position: relative;
}

.timeline-item:nth-child(odd) {
  flex-direction: row;
}

.timeline-item:nth-child(even) {
  flex-direction: row-reverse;
}

.timeline-dot {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  width: 16px;
  height: 16px;
  background: var(--primary);
  border-radius: 50%;
  border: 4px solid #fff;
  box-shadow: 0 0 0 4px var(--primary-bg);
  z-index: 2;
}

.timeline-content {
  width: calc(50% - 40px);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

.timeline-content .year {
  font-size: 14px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 8px;
}

.timeline-content h4 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 8px;
}

.timeline-content p {
  font-size: 14px;
  color: var(--text-secondary);
}

/* --- Products Page --- */
.product-section {
  padding: 0 0 100px;
}

.product-block {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: center;
  padding: 80px 0;
  border-bottom: 1px solid var(--border);
}

.product-block:last-child {
  border-bottom: none;
}

.product-block:nth-child(even) .product-image {
  order: -1;
}

.product-image {
  background: linear-gradient(135deg, var(--primary-bg), #f0f9ff);
  border-radius: var(--radius-lg);
  aspect-ratio: 4/3;
  display: flex;
  align-items: center;
  justify-content: center;
}

.product-image .icon-placeholder {
  font-size: 80px;
  opacity: 0.3;
}

.product-info h2 {
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 16px;
}

.product-info p {
  font-size: 16px;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 24px;
}

.product-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.product-tag {
  padding: 6px 16px;
  background: var(--bg-alt);
  border-radius: 20px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  border: 1px solid var(--border);
}

/* --- Contact Page --- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.2fr;
  gap: 60px;
  padding: 0 0 100px;
}

.contact-info h2 {
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 16px;
}

.contact-info > p {
  font-size: 16px;
  color: var(--text-secondary);
  margin-bottom: 40px;
  line-height: 1.8;
}

.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 28px;
}

.contact-item .icon {
  width: 48px;
  height: 48px;
  background: var(--primary-bg);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  flex-shrink: 0;
}

.contact-item h4 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 4px;
}

.contact-item p {
  font-size: 14px;
  color: var(--text-secondary);
}

.contact-form {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-md);
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-family: inherit;
  color: var(--text);
  background: var(--bg-alt);
  transition: all var(--transition);
  outline: none;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(26, 86, 219, 0.1);
  background: #fff;
}

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

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.btn-submit {
  width: 100%;
  padding: 16px;
  background: var(--primary);
  color: #fff;
  font-size: 16px;
  font-weight: 600;
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}

.btn-submit:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(26, 86, 219, 0.4);
}

/* --- Footer --- */
.footer {
  background: var(--bg-dark);
  color: #fff;
  padding: 60px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-brand h3 {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 12px;
}

.footer-brand p {
  font-size: 14px;
  color: #94a3b8;
  line-height: 1.8;
}

.footer-col h4 {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 20px;
  color: #cbd5e1;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.footer-col a {
  display: block;
  font-size: 14px;
  color: #94a3b8;
  margin-bottom: 12px;
  transition: color var(--transition);
}

.footer-col a:hover {
  color: #fff;
}

.footer-bottom {
  border-top: 1px solid #1e293b;
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-bottom p {
  font-size: 14px;
  color: #64748b;
}

.footer-bottom a {
  font-size: 14px;
  color: #94a3b8;
  margin-left: 24px;
  transition: color var(--transition);
}

.footer-bottom a:hover {
  color: #fff;
}

/* --- Animations --- */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* --- Responsive --- */
@media (max-width: 1024px) {
  .hero .container {
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .hero-content h1 {
    font-size: 40px;
  }

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

  .about-grid,
  .product-block {
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .product-block:nth-child(even) .product-image {
    order: 0;
  }

  .contact-grid {
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

  .section-title {
    font-size: 32px;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: #fff;
    flex-direction: column;
    padding: 24px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-md);
    gap: 12px;
  }

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

  .menu-toggle {
    display: flex;
  }

  .hero {
    padding: 120px 0 60px;
  }

  .hero-content h1 {
    font-size: 32px;
  }

  .hero-stats {
    grid-template-columns: 1fr;
  }

  .services-grid {
    grid-template-columns: 1fr;
  }

  .about-features {
    grid-template-columns: 1fr;
  }

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

  .footer-grid {
    grid-template-columns: 1fr;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

  .footer-bottom a {
    margin: 0 12px;
  }

  .section {
    padding: 60px 0;
  }

  .page-header {
    padding: 120px 0 48px;
  }

  .page-header h1 {
    font-size: 32px;
  }

  .section-title {
    font-size: 28px;
  }

  .timeline::before {
    left: 20px;
  }

  .timeline-item,
  .timeline-item:nth-child(even) {
    flex-direction: row;
    padding-left: 56px;
  }

  .timeline-dot {
    left: 20px;
  }

  .timeline-content {
    width: 100%;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  .hero-buttons {
    flex-direction: column;
  }

  .btn {
    justify-content: center;
  }
}

/* --- Page-specific helper --- */
.text-center { text-align: center; }
.mb-20 { margin-bottom: 20px; }
.mb-40 { margin-bottom: 40px; }
.mb-60 { margin-bottom: 60px; }
.mt-20 { margin-top: 20px; }
.mt-40 { margin-top: 40px; }

/* --- Banner Carousel --- */
.banner-carousel {
  position: relative;
  width: 100%;
  margin-top: 72px;
  overflow: hidden;
  background: var(--bg-dark);
}

.carousel-track {
  position: relative;
  width: 100%;
  height: 0;
  padding-bottom: 29.17%; /* 1920x560 比例 */
}

.carousel-slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity 0.8s ease;
  display: flex;
  align-items: center;
}

.carousel-slide.active {
  opacity: 1;
  z-index: 2;
}

.carousel-slide img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.carousel-caption {
  position: relative;
  z-index: 2;
  max-width: var(--max-width);
  margin: auto;
  padding: 80px 40px;
  width: 100%;
  text-align: left;
}

.carousel-caption h2 {
  font-size: 48px;
  font-weight: 800;
  color: #fff;
  line-height: 1.25;
  text-shadow: 0 2px 12px rgba(0,0,0,0.3);
  margin-bottom: 16px;
}

.carousel-caption p {
  font-size: 20px;
  color: rgba(255,255,255,0.9);
  text-shadow: 0 1px 8px rgba(0,0,0,0.3);
  max-width: 640px;
  line-height: 1.6;
  margin-bottom: 28px;
}

.carousel-caption .btn {
  text-shadow: none;
}

.carousel-arrow {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  z-index: 10;
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: rgba(255,255,255,0.25);
  color: #fff;
  font-size: 32px;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  transition: all var(--transition);
  border: none;
}

.carousel-arrow:hover {
  background: rgba(255,255,255,0.45);
}

.carousel-prev { left: 24px; }
.carousel-next { right: 24px; }

.carousel-dots {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 10;
  display: flex;
  gap: 10px;
}

.carousel-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: rgba(255,255,255,0.5);
  cursor: pointer;
  transition: all var(--transition);
  border: none;
}

.carousel-dot.active {
  background: #fff;
  width: 28px;
  border-radius: 5px;
}

@media (max-width: 1024px) {
  .carousel-caption h2 { font-size: 36px; }
  .carousel-caption p { font-size: 17px; }
}

@media (max-width: 768px) {
  .banner-carousel { margin-top: 72px; }
  .carousel-track { padding-bottom: 50%; }
  .carousel-caption h2 { font-size: 26px; }
  .carousel-caption p { font-size: 15px; margin-bottom: 18px; }
  .carousel-arrow { width: 40px; height: 40px; font-size: 24px; }
  .carousel-caption .btn { padding: 10px 22px; font-size: 14px; }
}

@media (max-width: 480px) {
  .carousel-track { padding-bottom: 60%; }
  .carousel-caption h2 { font-size: 22px; }
}