:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --accent: #f97316;
  --accent-light: #fff7ed;
  --text-main: #0f172a;
  --text-muted: #475569;
  --bg-page: #f8fafc;
  --bg-card: #ffffff;
  --border-color: #e2e8f0;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -2px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --transition: all 0.25s ease-in-out;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  background-color: var(--bg-page);
  color: var(--text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

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

.container {
  width: 100%;
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 20px;
  padding-right: 20px;
}

/* 顶部导航 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border-color);
}

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

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

.nav-brand .ai-page-logo {
  height: 40px;
  width: auto;
}

.nav-brand-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary);
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0;
  list-style: none;
}

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
}

.nav-links a:hover {
  color: var(--primary);
  background-color: #eff6ff;
}

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

.btn-nav-primary {
  background-color: var(--primary);
  color: #ffffff !important;
  font-size: 0.9rem;
  font-weight: 600;
  padding: 8px 18px;
  border-radius: 9999px;
  box-shadow: 0 2px 4px rgba(37, 99, 235, 0.2);
}

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

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.mobile-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--text-main);
  margin: 5px 0;
  transition: var(--transition);
}

/* 首屏 Hero（无图片纯 CSS） */
.hero-section {
  position: relative;
  background: linear-gradient(135deg, #eff6ff 0%, #ffffff 50%, #fff7ed 100%);
  padding: 80px 0 60px;
  border-bottom: 1px solid var(--border-color);
  overflow: hidden;
}

.hero-content {
  text-align: center;
  max-width: 860px;
  margin: 0 auto;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background-color: #dbeafe;
  color: var(--primary);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 9999px;
  margin-bottom: 20px;
}

.hero-title {
  font-size: 2.5rem;
  line-height: 1.25;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 20px;
  letter-spacing: -0.5px;
}

.hero-title span {
  color: var(--primary);
}

.hero-desc {
  font-size: 1.125rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 36px;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn-hero-main {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  color: #ffffff !important;
  font-size: 1.1rem;
  font-weight: 700;
  padding: 14px 32px;
  border-radius: 9999px;
  box-shadow: 0 6px 16px rgba(37, 99, 235, 0.3);
  transition: var(--transition);
}

.btn-hero-main:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(37, 99, 235, 0.4);
}

.btn-hero-sub {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: #ffffff;
  color: var(--text-main) !important;
  border: 1px solid var(--border-color);
  font-size: 1.1rem;
  font-weight: 600;
  padding: 14px 30px;
  border-radius: 9999px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.btn-hero-sub:hover {
  border-color: var(--primary);
  color: var(--primary) !important;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-top: 50px;
  background: #ffffff;
  padding: 24px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-color);
}

.stat-item {
  text-align: center;
  border-right: 1px solid var(--border-color);
}

.stat-item:last-child {
  border-right: none;
}

.stat-num {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 4px;
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* 模块公共样式 */
.section-pad {
  padding: 70px 0;
}

.section-pad-alt {
  background-color: #ffffff;
  padding: 70px 0;
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 50px;
}

.section-tag {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent);
  background-color: var(--accent-light);
  padding: 4px 12px;
  border-radius: 9999px;
  margin-bottom: 12px;
}

.section-title {
  font-size: 2rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 12px;
  letter-spacing: -0.5px;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--text-muted);
}

/* 平台能力卡片 */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 30px;
}

.card-item {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.card-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: #cbd5e1;
}

.card-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: #eff6ff;
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  font-weight: bold;
  margin-bottom: 16px;
}

.card-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 10px;
}

.card-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
  flex-grow: 1;
}

/* 模型支持标签云 */
.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  margin-top: 30px;
}

.model-tag {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 8px 16px;
  border-radius: 9999px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.model-tag:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: #eff6ff;
}

/* 场景卡片矩阵 */
.scene-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
  transition: var(--transition);
}

.scene-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
}

.scene-card h4 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.scene-card h4::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 14px;
  background-color: var(--accent);
  border-radius: 2px;
}

.scene-card p {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* 对比评测表格 */
.compare-box {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 30px;
  box-shadow: var(--shadow-md);
}

.score-badge {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  background: #ecfdf5;
  border: 1px solid #a7f3d0;
  color: #065f46;
  padding: 10px 20px;
  border-radius: 9999px;
  font-weight: 700;
  margin-bottom: 24px;
}

.score-badge .score-val {
  font-size: 1.25rem;
  color: #059669;
}

.table-responsive {
  width: 100%;
  overflow-x: auto;
}

.compare-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
}

.compare-table th,
.compare-table td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border-color);
  font-size: 0.95rem;
}

.compare-table th {
  background-color: #f8fafc;
  font-weight: 700;
  color: var(--text-main);
}

.compare-table .highlight-col {
  background-color: #eff6ff;
  color: var(--primary);
  font-weight: 700;
}

/* 步骤流程 */
.step-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.step-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px 20px;
  text-align: center;
  position: relative;
}

.step-idx {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--primary);
  color: #ffffff;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 14px;
}

.step-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.step-desc {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* 案例展示 */
.case-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

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

.case-img-wrap {
  width: 100%;
  overflow: hidden;
  background-color: #f1f5f9;
}

.case-body {
  padding: 20px;
}

.case-tag {
  font-size: 0.75rem;
  color: var(--primary);
  font-weight: 600;
  background: #eff6ff;
  padding: 2px 8px;
  border-radius: 4px;
  display: inline-block;
  margin-bottom: 8px;
}

.case-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.case-text {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* 需求表单 */
.form-box {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px;
  box-shadow: var(--shadow-md);
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin-bottom: 20px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.form-group.full-width {
  grid-column: span 2;
}

.form-label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-main);
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  color: var(--text-main);
  background-color: #f8fafc;
  outline: none;
  transition: var(--transition);
  font-family: inherit;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  border-color: var(--primary);
  background-color: #ffffff;
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.form-btn {
  background: var(--primary);
  color: #ffffff;
  border: none;
  padding: 14px 28px;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
  width: 100%;
}

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

/* FAQ 手风琴 */
.faq-wrap {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.faq-item {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
}

.faq-question {
  width: 100%;
  padding: 18px 20px;
  text-align: left;
  background: none;
  border: none;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-main);
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
}

.faq-question::after {
  content: "+";
  font-size: 1.4rem;
  color: var(--primary);
  line-height: 1;
}

.faq-item.active .faq-question::after {
  content: "−";
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out;
  padding: 0 20px;
  background-color: #f8fafc;
}

.faq-item.active .faq-answer {
  padding: 16px 20px;
  border-top: 1px solid var(--border-color);
}

.faq-answer p {
  font-size: 0.925rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* 客户评价 */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.review-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.review-text {
  font-size: 0.925rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 16px;
  font-style: italic;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 12px;
  border-top: 1px solid #f1f5f9;
  padding-top: 12px;
}

.author-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: #e0e7ff;
  color: var(--primary);
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.95rem;
}

.author-meta h5 {
  font-size: 0.95rem;
  color: var(--text-main);
}

.author-meta span {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* 资讯与友情链接 */
.links-box {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
  margin-top: 20px;
}

.links-box h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-main);
}

.links-flex {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.links-flex a {
  font-size: 0.875rem;
  color: var(--text-muted);
  background: #f8fafc;
  padding: 6px 12px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

.links-flex a:hover {
  color: var(--primary);
  border-color: var(--primary);
}

/* 页脚 */
.site-footer {
  background-color: #0f172a;
  color: #94a3b8;
  padding: 60px 0 30px;
  font-size: 0.9rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 30px;
  margin-bottom: 40px;
}

.footer-info h4 {
  color: #ffffff;
  font-size: 1.1rem;
  margin-bottom: 12px;
}

.footer-info p {
  line-height: 1.6;
  margin-bottom: 8px;
}

.footer-nav h5 {
  color: #ffffff;
  font-size: 1rem;
  margin-bottom: 16px;
}

.footer-nav ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.footer-nav a {
  color: #94a3b8;
}

.footer-nav a:hover {
  color: #ffffff;
}

.footer-qr-box {
  text-align: center;
}

.footer-qr-img {
  width: 100px;
  height: 100px;
  margin: 0 auto 8px;
  border-radius: 6px;
  background: #ffffff;
  padding: 4px;
}

.footer-bottom {
  text-align: center;
  padding-top: 24px;
  border-top: 1px solid #1e293b;
  font-size: 0.85rem;
}

/* 悬浮客服 */
.float-contact {
  position: fixed;
  right: 20px;
  bottom: 30px;
  z-index: 999;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.float-btn {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--primary);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  cursor: pointer;
  border: none;
  transition: var(--transition);
}

.float-btn:hover {
  transform: scale(1.08);
  background: var(--primary-hover);
}

/* 响应式适配 */
@media (max-width: 992px) {
  .grid-4, .step-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .grid-3, .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 72px;
    left: 0;
    width: 100%;
    background: #ffffff;
    flex-direction: column;
    padding: 20px;
    box-shadow: var(--shadow-md);
    border-bottom: 1px solid var(--border-color);
  }
  .nav-links.active {
    display: flex;
  }
  .mobile-toggle {
    display: block;
  }
  .hero-title {
    font-size: 1.85rem;
  }
  .hero-stats {
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
  }
  .stat-item {
    border-right: none;
  }
  .grid-3, .grid-2, .reviews-grid, .form-grid {
    grid-template-columns: 1fr;
  }
  .form-group.full-width {
    grid-column: span 1;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
}