/* ==========================================================================
   大象网络 (Elephant Network) - 纯原生 CSS 浅色样式表
   极致秒开 · 响应式适配 · 浅色科技极简风
   ========================================================================== */

/* 全局 CSS 变量（浅色主题） */
:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --text-main: #0f172a;
  --text-muted: #334155;
  --text-light: #64748b;
  
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --primary-gradient: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);
  
  --accent: #0284c7;
  --accent-light: #e0f2fe;
  --badge-bg: #dbeafe;
  --badge-text: #1e40af;
  
  --border: #e2e8f0;
  --border-hover: #cbd5e1;
  --card-bg: #ffffff;
  
  --shadow-sm: 0 1px 3px 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, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --shadow-hover: 0 20px 25px -5px rgba(37, 99, 235, 0.12), 0 8px 10px -6px rgba(37, 99, 235, 0.08);
  
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-full: 9999px;
  
  --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
}

/* 基础重置 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-secondary);
  color: var(--text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* 常用组件 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 28px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  transition: var(--transition);
  cursor: pointer;
  border: none;
  text-align: center;
  white-space: nowrap;
}

.btn-primary {
  background: var(--primary-gradient);
  color: #ffffff !important;
  box-shadow: 0 4px 14px 0 rgba(37, 99, 235, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px 0 rgba(37, 99, 235, 0.45);
  background: linear-gradient(135deg, #2563eb 0%, #1e40af 100%);
}

.btn-secondary {
  background-color: var(--bg-primary);
  color: var(--text-main) !important;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
  background-color: var(--bg-tertiary);
  border-color: var(--border-hover);
  transform: translateY(-2px);
}

.btn-block {
  width: 100%;
}

.badge {
  display: inline-block;
  padding: 6px 14px;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--badge-text);
  background-color: var(--badge-bg);
  border-radius: var(--radius-full);
  margin-bottom: 16px;
}

.section-title-wrap {
  text-align: center;
  margin-bottom: 50px;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.025em;
  margin-bottom: 12px;
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--text-muted);
  max-width: 650px;
  margin: 0 auto;
}

/* 顶部导航 */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 76px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--text-main);
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: var(--primary-gradient);
  color: #fff;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.25);
}

.nav-links {
  display: flex;
  gap: 30px;
  list-style: none;
}

.nav-links a {
  font-weight: 500;
  color: var(--text-muted);
}

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

/* 核心 Hero 主视觉区 */
.hero {
  padding: 90px 0 70px;
  background: radial-gradient(circle at 50% 0%, #eff6ff 0%, #ffffff 70%);
  text-align: center;
}

.hero-content {
  max-width: 850px;
  margin: 0 auto;
}

.hero-headline {
  font-size: 3.25rem;
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: -0.03em;
  color: var(--text-main);
  margin-bottom: 24px;
}

.hero-headline span {
  background: linear-gradient(135deg, #2563eb 0%, #0284c7 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-muted);
  margin-bottom: 36px;
  line-height: 1.7;
}

.hero-cta-group {
  display: flex;
  gap: 16px;
  justify-content: center;
  align-items: center;
  margin-bottom: 48px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 50px;
  padding-top: 40px;
  border-top: 1px solid var(--border);
}

.stat-item h4 {
  font-size: 2rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 4px;
}

.stat-item p {
  font-size: 0.95rem;
  color: var(--text-light);
}

/* 产品核心优势 */
.advantages {
  padding: 90px 0;
  background-color: var(--bg-primary);
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
}

.adv-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  transition: var(--transition);
}

.adv-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
  border-color: var(--border-hover);
  background-color: var(--bg-primary);
}

.adv-icon {
  width: 56px;
  height: 56px;
  background-color: var(--primary-light);
  color: var(--primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 20px;
}

.adv-card h3 {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-main);
}

.adv-card p {
  color: var(--text-muted);
  font-size: 0.975rem;
}

/* 流媒体与 AI 支持 */
.media-ai {
  padding: 90px 0;
  background-color: var(--bg-secondary);
}

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

.service-item {
  background-color: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 24px 20px;
  text-align: center;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.service-item:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.service-logo {
  font-size: 2.2rem;
  margin-bottom: 10px;
}

.service-name {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text-main);
  margin-bottom: 4px;
}

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

/* 套餐价格对比 */
.pricing {
  padding: 90px 0;
  background-color: var(--bg-primary);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
  align-items: stretch;
}

.price-card {
  position: relative;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 40px 30px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition);
}

.price-card.popular {
  background-color: var(--bg-primary);
  border: 2px solid var(--primary);
  box-shadow: var(--shadow-lg);
  transform: scale(1.03);
}

.popular-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary-gradient);
  color: #fff;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 4px 16px;
  border-radius: var(--radius-full);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.price-header h3 {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 8px;
}

.price-header p {
  color: var(--text-light);
  font-size: 0.9rem;
  margin-bottom: 20px;
}

.price-val {
  font-size: 2.75rem;
  font-weight: 900;
  color: var(--text-main);
  margin-bottom: 24px;
}

.price-val span {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-light);
}

.feature-list {
  list-style: none;
  margin-bottom: 32px;
  flex-grow: 1;
}

.feature-list li {
  padding: 10px 0;
  font-size: 0.95rem;
  color: var(--text-muted);
  border-bottom: 1px dashed var(--border);
  display: flex;
  align-items: center;
  gap: 10px;
}

.feature-list li::before {
  content: "✓";
  color: var(--primary);
  font-weight: bold;
}

/* 用户评价 */
.reviews {
  padding: 90px 0;
  background-color: var(--bg-secondary);
}

.review-card {
  background-color: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 30px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.review-card:hover {
  box-shadow: var(--shadow-md);
}

.review-rating {
  color: #f59e0b;
  margin-bottom: 14px;
  font-size: 1.1rem;
}

.review-text {
  color: var(--text-muted);
  font-size: 0.975rem;
  line-height: 1.7;
  margin-bottom: 20px;
}

.review-user {
  display: flex;
  align-items: center;
  gap: 12px;
}

.avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--accent-light);
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
}

.user-info h5 {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-main);
}

.user-info p {
  font-size: 0.8rem;
  color: var(--text-light);
}

/* FAQ 常见问题解答 */
.faq {
  padding: 90px 0;
  background-color: var(--bg-primary);
}

.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background-color: var(--bg-secondary);
  padding: 24px;
}

.faq-question {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.faq-question::before {
  content: "Q.";
  color: var(--primary);
  font-weight: 800;
}

.faq-answer {
  color: var(--text-muted);
  font-size: 0.95rem;
  padding-left: 26px;
  line-height: 1.6;
}

/* 页脚 (只保留 4 个新页面跳转标题) */
.footer {
  background-color: var(--bg-primary);
  border-top: 1px solid var(--border);
  padding: 50px 0 30px;
  text-align: center;
}

.footer-nav {
  display: flex;
  justify-content: center;
  gap: 40px;
  margin-bottom: 30px;
}

.footer-nav a {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-main);
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.footer-nav a:hover {
  background-color: var(--primary-light);
  color: var(--primary);
}

.copyright {
  color: var(--text-light);
  font-size: 0.875rem;
}

/* 通用文档页 (subpages) 样式 */
.page-header {
  padding: 60px 0 40px;
  background: var(--primary-light);
  border-bottom: 1px solid var(--border);
  margin-bottom: 40px;
}

.page-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 10px;
}

.page-desc {
  color: var(--text-muted);
  font-size: 1.1rem;
}

.content-box {
  background-color: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 40px;
  margin-bottom: 60px;
  box-shadow: var(--shadow-sm);
}

.content-box h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-main);
  margin: 28px 0 14px;
  border-bottom: 2px solid var(--primary-light);
  padding-bottom: 8px;
}

.content-box h2:first-child {
  margin-top: 0;
}

.content-box p {
  color: var(--text-muted);
  font-size: 1rem;
  margin-bottom: 16px;
  line-height: 1.7;
}

.content-box ul {
  margin-bottom: 20px;
  padding-left: 20px;
  color: var(--text-muted);
}

.content-box li {
  margin-bottom: 8px;
  line-height: 1.6;
}

/* ==========================================================================
   响应式媒体查询 (@media) - 手机端完美适配
   ========================================================================== */

@media (max-width: 992px) {
  .hero-headline {
    font-size: 2.5rem;
  }
  .grid-3, .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .service-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .price-card.popular {
    transform: none;
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }

  .header {
    position: relative;
  }

  .nav-container {
    height: 64px;
  }

  .nav-links {
    display: none; /* 移动端隐藏冗余顶部菜单，直奔主题 */
  }

  .hero {
    padding: 50px 0 40px;
  }

  .hero-headline {
    font-size: 2.1rem;
    line-height: 1.3;
  }

  .hero-subtitle {
    font-size: 1.05rem;
    margin-bottom: 28px;
  }

  .hero-cta-group {
    flex-direction: column;
    width: 100%;
    gap: 12px;
  }

  .btn {
    width: 100%;
    min-height: 50px; /* 触屏友好高度 */
    font-size: 1.05rem;
  }

  .hero-stats {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .grid-3, .service-grid, .pricing-grid {
    grid-template-columns: 1fr;
  }

  .section-title {
    font-size: 1.75rem;
  }

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

  .footer-nav {
    flex-direction: column;
    gap: 16px;
    align-items: center;
  }

  .footer-nav a {
    width: 100%;
    text-align: center;
  }

  .content-box {
    padding: 24px 18px;
  }

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

/* ==========================================================================
   高科技网格卡片 (High-Tech Article Grid Cards)
   ========================================================================== */
.article-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  margin-top: 36px;
  margin-bottom: 50px;
}

.tech-card {
  background: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
}

.tech-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--primary-gradient);
  opacity: 0;
  transition: var(--transition);
}

.tech-card:hover {
  transform: translateY(-6px);
  border-color: var(--primary);
  box-shadow: var(--shadow-hover);
}

.tech-card:hover::before {
  opacity: 1;
}

.tech-card-badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--primary);
  background-color: var(--primary-light);
  padding: 4px 12px;
  border-radius: var(--radius-full);
  margin-bottom: 14px;
  width: fit-content;
}

.tech-card-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.45;
  margin-bottom: 12px;
}

.tech-card-snippet {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 20px;
  flex-grow: 1;
}

.tech-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  border-top: 1px dashed var(--border);
}

.tech-card-meta {
  font-size: 0.8rem;
  color: var(--text-light);
}

.tech-card-link {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 4px;
}

.tech-card-link:hover {
  color: var(--primary-hover);
}