/* ==========================================================================
   云图机场 (Yuntu Airport) - 纯 CSS 极致极速响应式样式表
   ========================================================================== */

/* 1. 全局变量与 Reset */
:root {
  --primary-color: #3b82f6;
  --primary-hover: #2563eb;
  --primary-gradient: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
  --secondary-gradient: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);
  --accent-gradient: linear-gradient(135deg, #f59e0b 0%, #ef4444 100%);
  --bg-dark: #0f172a;
  --bg-card: rgba(30, 41, 59, 0.7);
  --bg-card-hover: rgba(30, 41, 59, 0.95);
  --border-color: rgba(255, 255, 255, 0.1);
  --border-highlight: rgba(59, 130, 246, 0.4);
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-sub: #cbd5e1;
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --shadow-glow: 0 0 25px rgba(59, 130, 246, 0.25);
  --shadow-card: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
  --max-width: 1200px;
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

html {
  scroll-behavior: smooth;
  font-family: var(--font-family);
  background-color: var(--bg-dark);
  color: var(--text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body {
  overflow-x: hidden;
  min-height: 100vh;
  background: radial-gradient(circle at 50% -20%, #1e1b4b 0%, #0f172a 70%);
}

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

/* 2. 通用布局组件 */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

.section-padding {
  padding: 80px 0;
}

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

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  background: rgba(59, 130, 246, 0.15);
  border: 1px solid rgba(59, 130, 246, 0.3);
  border-radius: 50px;
  color: #60a5fa;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 20px;
}

.badge-dot {
  width: 8px;
  height: 8px;
  background-color: #10b981;
  border-radius: 50%;
  box-shadow: 0 0 8px #10b981;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.025em;
  margin-bottom: 16px;
  background: linear-gradient(180deg, #ffffff 0%, #94a3b8 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--text-muted);
  max-width: 680px;
  margin: 0 auto 50px auto;
}

/* 3. 按钮 (CTA) 规范与样式 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  font-size: 1rem;
  font-weight: 700;
  border-radius: var(--radius-sm);
  transition: all 0.3s ease;
  cursor: pointer;
  text-align: center;
  white-space: nowrap;
}

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

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 35px rgba(59, 130, 246, 0.45);
  filter: brightness(1.1);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.25);
  transform: translateY(-2px);
}

.btn-block {
  width: 100%;
}

.btn-lg {
  padding: 16px 36px;
  font-size: 1.125rem;
  border-radius: 12px;
}

/* 4. Header 导航 */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.35rem;
  font-weight: 800;
  color: #ffffff;
  letter-spacing: -0.5px;
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: var(--primary-gradient);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.logo-icon svg {
  width: 22px;
  height: 22px;
  fill: none;
  stroke: #ffffff;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

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

.nav-links a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-sub);
  transition: color 0.2s;
}

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

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

/* 5. Hero 视觉区 */
.hero {
  padding: 90px 0 70px 0;
  position: relative;
  text-align: center;
}

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

.hero-title {
  font-size: 3.25rem;
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: 24px;
  letter-spacing: -1px;
}

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

.hero-desc {
  font-size: 1.25rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 40px;
}

.hero-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-bottom: 50px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  max-width: 900px;
  margin: 0 auto;
  padding: 24px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  backdrop-filter: blur(10px);
}

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

.stat-value {
  font-size: 1.75rem;
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 4px;
}

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

/* 6. 核心优势 */
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 32px 24px;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

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

.feature-icon {
  width: 54px;
  height: 54px;
  background: rgba(59, 130, 246, 0.12);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  color: #3b82f6;
}

.feature-icon svg {
  width: 28px;
  height: 28px;
  stroke: currentColor;
  stroke-width: 2;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: #ffffff;
}

.feature-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* 7. 流媒体与 AI 支持 */
.support-section {
  background: rgba(15, 23, 42, 0.6);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

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

.support-box {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 36px;
  position: relative;
  overflow: hidden;
}

.support-box::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--primary-gradient);
}

.support-box.ai::before {
  background: var(--secondary-gradient);
}

.support-box-title {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.support-box-desc {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 24px;
}

.tags-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.tag-item {
  padding: 8px 16px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 8px;
}

.tag-item svg {
  width: 16px;
  height: 16px;
  fill: #10b981;
}

/* 8. 套餐价格表 */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 36px 24px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all 0.3s ease;
}

.pricing-card:hover {
  transform: translateY(-6px);
  border-color: rgba(255, 255, 255, 0.2);
}

.pricing-card.popular {
  background: rgba(30, 41, 59, 0.9);
  border: 2px solid #3b82f6;
  box-shadow: var(--shadow-glow);
}

.popular-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary-gradient);
  color: #ffffff;
  padding: 4px 16px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.plan-name {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: #ffffff;
}

.plan-desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 24px;
}

.plan-price {
  margin-bottom: 24px;
}

.price-currency {
  font-size: 1.25rem;
  font-weight: 700;
  color: #3b82f6;
}

.price-amount {
  font-size: 2.75rem;
  font-weight: 900;
  color: #ffffff;
  line-height: 1;
}

.price-period {
  font-size: 0.875rem;
  color: var(--text-muted);
}

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

.plan-features li {
  font-size: 0.9rem;
  color: var(--text-sub);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.plan-features li svg {
  width: 18px;
  height: 18px;
  stroke: #10b981;
  stroke-width: 2.5;
  fill: none;
  flex-shrink: 0;
}

/* 9. 用户评价 */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.review-stars {
  color: #f59e0b;
  font-size: 1rem;
  margin-bottom: 14px;
}

.review-text {
  font-size: 0.95rem;
  color: var(--text-sub);
  line-height: 1.6;
  margin-bottom: 20px;
  font-style: italic;
}

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

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

.user-info-name {
  font-size: 0.95rem;
  font-weight: 700;
  color: #ffffff;
}

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

/* 10. FAQ 常见问题 (纯 CSS accordion) */
.faq-container {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  margin-bottom: 16px;
  overflow: hidden;
  transition: border-color 0.2s;
}

.faq-item summary {
  padding: 20px 24px;
  font-size: 1.05rem;
  font-weight: 700;
  color: #ffffff;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  font-size: 1.5rem;
  font-weight: 400;
  color: var(--text-muted);
  transition: transform 0.3s;
}

.faq-item[open] summary::after {
  transform: rotate(45deg);
  color: #3b82f6;
}

.faq-item[open] {
  border-color: var(--border-highlight);
}

.faq-answer {
  padding: 0 24px 20px 24px;
  color: var(--text-sub);
  font-size: 0.95rem;
  line-height: 1.7;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  margin-top: 4px;
  padding-top: 16px;
}

/* 11. 高科技 SEO 文章网格卡片 (Grid Cards) */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 35px;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all 0.3s ease;
  backdrop-filter: blur(10px);
}

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

.article-tag {
  display: inline-block;
  padding: 4px 12px;
  background: rgba(59, 130, 246, 0.15);
  border: 1px solid rgba(59, 130, 246, 0.3);
  border-radius: 20px;
  font-size: 0.8rem;
  color: #60a5fa;
  font-weight: 600;
  margin-bottom: 14px;
  align-self: flex-start;
}

.article-card-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 12px;
  line-height: 1.45;
}

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

.article-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}

/* 12. 独立子页面共享样式 */
.subpage-body {
  background: #0f172a;
}

.subpage-header {
  padding: 40px 0;
  background: rgba(30, 41, 59, 0.4);
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 50px;
}

.subpage-title {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.subpage-content {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 40px;
  margin-bottom: 80px;
  line-height: 1.8;
  color: var(--text-sub);
}

.subpage-content h2 {
  font-size: 1.5rem;
  color: #ffffff;
  margin: 30px 0 16px 0;
  padding-bottom: 8px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

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

.subpage-content p {
  margin-bottom: 16px;
}

.subpage-content ul {
  margin-bottom: 20px;
  padding-left: 24px;
}

.subpage-content li {
  margin-bottom: 8px;
}

/* 13. 页脚 (Footer) - 严格按需求仅保留 4 个标题链接 */
.footer {
  background: #090d16;
  border-top: 1px solid var(--border-color);
  padding: 50px 0 30px 0;
}

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

.footer-nav a {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-sub);
  transition: color 0.2s ease;
}

.footer-nav a:hover {
  color: #3b82f6;
  text-decoration: underline;
}

.footer-copyright {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.875rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 24px;
}

/* 14. 响应式媒体查询 (@media Queries) */
@media (max-width: 1024px) {
  .hero-title {
    font-size: 2.75rem;
  }
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .articles-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .header-container {
    height: 64px;
  }
  .nav-links {
    display: none;
  }
  .hero {
    padding: 50px 0 40px 0;
  }
  .hero-title {
    font-size: 2rem;
  }
  .hero-desc {
    font-size: 1rem;
  }
  .hero-cta {
    flex-direction: column;
    width: 100%;
  }
  .hero-cta .btn {
    width: 100%;
  }
  .hero-stats {
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
  }
  .stat-value {
    font-size: 1.4rem;
  }
  .features-grid {
    grid-template-columns: 1fr;
  }
  .support-grid {
    grid-template-columns: 1fr;
  }
  .pricing-grid {
    grid-template-columns: 1fr;
  }
  .pricing-card.popular {
    transform: none;
  }
  .reviews-grid {
    grid-template-columns: 1fr;
  }
  .articles-grid {
    grid-template-columns: 1fr;
  }
  .subpage-content {
    padding: 24px 18px;
  }
  .footer-nav {
    flex-direction: column;
    gap: 18px;
  }
}