:root {
  --primary-gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 50%, #ec4899 100%);
  --rainbow-subtle: linear-gradient(135deg, rgba(99, 102, 241, 0.08) 0%, rgba(168, 85, 247, 0.08) 50%, rgba(236, 72, 153, 0.08) 100%);
  --rainbow-border: linear-gradient(90deg, #6366f1, #a855f7, #ec4899, #f59e0b, #10b981);
  --primary-color: #6366f1;
  --secondary-color: #ec4899;
  --dark-text: #0f172a;
  --muted-text: #475569;
  --light-bg: #f8fafc;
  --white: #ffffff;
  --border-color: #e2e8f0;
  --radius-lg: 16px;
  --radius-md: 10px;
  --shadow-sm: 0 2px 8px rgba(15, 23, 42, 0.04);
  --shadow-md: 0 10px 30px rgba(15, 23, 42, 0.08);
  --shadow-rainbow: 0 10px 25px rgba(99, 102, 241, 0.25);
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--dark-text);
  background-color: var(--light-bg);
  line-height: 1.6;
}

body {
  width: 100%;
  overflow-x: hidden;
}

/* 统一容器控制 */
.ai-container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Rainbow 饰条 */
.rainbow-bar {
  height: 4px;
  background: var(--rainbow-border);
  width: 100%;
}

/* 顶部导航 */
.header-nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

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

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

.ai-page-logo {
  height: 40px;
  width: auto;
  display: block;
}

.brand-name {
  font-size: 20px;
  font-weight: 800;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.5px;
}

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

.nav-links li a {
  display: inline-block;
  padding: 8px 14px;
  color: var(--dark-text);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: var(--transition);
  border-radius: 6px;
}

.nav-links li a:hover,
.nav-links li a.active {
  color: var(--primary-color);
  background: rgba(99, 102, 241, 0.08);
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 22px;
  font-size: 14px;
  font-weight: 600;
  border-radius: 50px;
  text-decoration: none;
  transition: var(--transition);
  cursor: pointer;
  border: none;
}

.btn-rainbow {
  background: var(--primary-gradient);
  color: #ffffff !important;
  box-shadow: var(--shadow-rainbow);
}

.btn-rainbow:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 28px rgba(168, 85, 247, 0.35);
}

.btn-outline {
  background: transparent;
  border: 1px solid var(--primary-color);
  color: var(--primary-color);
}

.btn-outline:hover {
  background: rgba(99, 102, 241, 0.08);
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 24px;
  color: var(--dark-text);
  cursor: pointer;
}

/* 模块通用样式 */
.section-padding {
  padding: 80px 0;
  position: relative;
}

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

.section-bg-rainbow {
  background: var(--rainbow-subtle);
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 50px auto;
}

.badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 30px;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  background: rgba(99, 102, 241, 0.1);
  color: var(--primary-color);
  margin-bottom: 12px;
  border: 1px solid rgba(99, 102, 241, 0.2);
}

.section-title {
  font-size: 32px;
  font-weight: 800;
  color: var(--dark-text);
  margin-bottom: 16px;
  line-height: 1.3;
}

.section-subtitle {
  font-size: 16px;
  color: var(--muted-text);
}

/* 首屏 HERO 区域 - 严禁出现图片 */
.hero-section {
  padding: 90px 0 70px 0;
  background: radial-gradient(circle at 50% 20%, rgba(168, 85, 247, 0.12) 0%, rgba(248, 250, 252, 1) 70%);
  text-align: center;
}

.hero-h1 {
  font-size: 40px;
  font-weight: 900;
  line-height: 1.25;
  margin-bottom: 20px;
  color: var(--dark-text);
  letter-spacing: -0.5px;
}

.hero-h1 span {
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-desc {
  font-size: 18px;
  color: var(--muted-text);
  max-width: 800px;
  margin: 0 auto 36px auto;
  line-height: 1.7;
}

.hero-btns {
  display: flex;
  justify-content: center;
  gap: 16px;
  margin-bottom: 60px;
  flex-wrap: wrap;
}

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

.metric-card {
  background: var(--white);
  padding: 24px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  text-align: center;
}

.metric-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: rgba(168, 85, 247, 0.4);
}

.metric-num {
  font-size: 32px;
  font-weight: 800;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 6px;
}

.metric-label {
  font-size: 14px;
  color: var(--muted-text);
  font-weight: 500;
}

/* 卡片网格 */
.card-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

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

.feature-card {
  background: var(--white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
  border-color: rgba(99, 102, 241, 0.3);
}

.feature-icon-box {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: var(--rainbow-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  margin-bottom: 20px;
  color: var(--primary-color);
}

.feature-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--dark-text);
}

.feature-card p {
  font-size: 14px;
  color: var(--muted-text);
  line-height: 1.6;
}

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

.tag-item {
  background: var(--white);
  border: 1px solid var(--border-color);
  padding: 8px 16px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 600;
  color: var(--dark-text);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.tag-item:hover {
  border-color: var(--secondary-color);
  color: var(--secondary-color);
  transform: scale(1.05);
}

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

.process-card {
  background: var(--white);
  padding: 30px 20px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  text-align: center;
  position: relative;
}

.process-step-num {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--primary-gradient);
  color: #fff;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px auto;
}

/* 对比评测 */
.rating-highlight {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  background: var(--white);
  border: 2px solid rgba(168, 85, 247, 0.3);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-bottom: 40px;
  box-shadow: var(--shadow-sm);
}

.score-num {
  font-size: 48px;
  font-weight: 900;
  color: #f59e0b;
}

.stars {
  color: #f59e0b;
  font-size: 24px;
  letter-spacing: 2px;
}

.comparison-table-wrapper {
  overflow-x: auto;
  background: var(--white);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  min-width: 700px;
}

.comparison-table th,
.comparison-table td {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-color);
  font-size: 14px;
}

.comparison-table th {
  background: #f1f5f9;
  font-weight: 700;
  color: var(--dark-text);
}

.comparison-table th.highlight-col {
  background: rgba(99, 102, 241, 0.1);
  color: var(--primary-color);
}

.comparison-table td.highlight-col {
  background: rgba(99, 102, 241, 0.03);
  font-weight: 600;
  color: var(--primary-color);
}

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

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

.case-img-box {
  width: 100%;
  overflow: hidden;
  background: #e2e8f0;
}

.ai-page-image {
  width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
}

.case-info {
  padding: 20px;
}

.case-info h4 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 8px;
}

.case-info p {
  font-size: 13px;
  color: var(--muted-text);
}

/* 评论卡片 */
.review-card {
  background: var(--white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 16px;
}

.avatar-circle {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--primary-gradient);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
}

/* FAQ 手风琴 */
.faq-list {
  max-width: 900px;
  margin: 0 auto;
}

.faq-item {
  background: var(--white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  overflow: hidden;
}

.faq-question {
  width: 100%;
  padding: 18px 24px;
  text-align: left;
  background: none;
  border: none;
  font-size: 16px;
  font-weight: 700;
  color: var(--dark-text);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out;
  padding: 0 24px;
  background: #fafafa;
}

.faq-answer p {
  padding: 16px 0;
  font-size: 14px;
  color: var(--muted-text);
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 200px;
}

.faq-item.active .faq-question {
  color: var(--primary-color);
}

/* 表单与联系区 */
.contact-wrapper {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: start;
}

.form-box {
  background: var(--white);
  padding: 36px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  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(--dark-text);
}

.form-control {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 14px;
  outline: none;
  transition: var(--transition);
}

.form-control:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

textarea.form-control {
  min-height: 110px;
  resize: vertical;
}

.contact-info-card {
  background: var(--white);
  padding: 30px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  margin-bottom: 20px;
}

.qr-code-img {
  width: 130px;
  height: 130px;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  padding: 4px;
}

/* 友情链接与页脚 */
.footer-section {
  background: #0f172a;
  color: #94a3b8;
  padding-top: 60px;
  padding-bottom: 30px;
  font-size: 14px;
}

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

.footer-col h4 {
  color: #ffffff;
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 20px;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 10px;
}

.footer-links a {
  color: #94a3b8;
  text-decoration: none;
  transition: var(--transition);
}

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

.friend-links-box {
  border-top: 1px solid #1e293b;
  padding-top: 24px;
  margin-top: 30px;
}

.friend-links-box h5 {
  color: #cbd5e1;
  font-size: 14px;
  margin-bottom: 12px;
}

.friend-links-list {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.friend-links-list a {
  color: #64748b;
  text-decoration: none;
  font-size: 13px;
  transition: var(--transition);
}

.friend-links-list a:hover {
  color: #38bdf8;
}

.copyright-bar {
  border-top: 1px solid #1e293b;
  padding-top: 24px;
  margin-top: 30px;
  text-align: center;
  font-size: 13px;
  color: #64748b;
}

/* 浮动客服入口 */
.floating-widget {
  position: fixed;
  bottom: 30px;
  right: 30px;
  z-index: 999;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.float-btn {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: var(--primary-gradient);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-rainbow);
  text-decoration: none;
  font-size: 20px;
  cursor: pointer;
  transition: var(--transition);
}

.float-btn:hover {
  transform: scale(1.1);
}

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

@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }
  .nav-links {
    display: none;
    position: absolute;
    top: 72px;
    left: 0;
    width: 100%;
    background: #ffffff;
    flex-direction: column;
    padding: 20px 0;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
  }
  .nav-links.active {
    display: flex;
  }
  .nav-links li {
    width: 100%;
    text-align: center;
  }
  .hero-h1 {
    font-size: 28px;
  }
  .hero-desc {
    font-size: 15px;
  }
  .card-grid-4, .card-grid-3, .metrics-grid, .process-grid {
    grid-template-columns: 1fr;
  }
  .footer-grid {
    grid-template-columns: 1fr;
  }
}