/* ==========================================================================
   云图机场 (Yuntu Accelerator) - 极简高性能原生样式表
   零外部依赖 | 秒开加载 | 响应式自适应 | 无障碍优化 (WCAG 2.1 AA)
   ========================================================================== */

:root {
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-surface-hover: #f1f5f9;
  --color-text-main: #0f172a;
  --color-text-muted: #475569;
  --color-text-light: #64748b;
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-light: #eff6ff;
  --color-primary-border: #bfdbfe;
  --color-border: #e2e8f0;
  --color-border-dark: #cbd5e1;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-tag: #e0e7ff;
  --color-tag-text: #3730a3;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 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);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;
  --max-width: 1140px;
  --header-height: 68px;
}

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

html {
  font-family: var(--font-family);
  font-size: 16px;
  line-height: 1.65;
  color: var(--color-text-main);
  background-color: var(--color-bg);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* 跳转至主要内容 (Accessibility Skip Link) */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  background: var(--color-primary);
  color: #ffffff;
  padding: 0.75rem 1.25rem;
  z-index: 9999;
  border-radius: var(--radius-sm);
  text-decoration: none;
  font-weight: 600;
  transition: top 0.2s ease;
}
.skip-link:focus {
  top: 1rem;
  outline: 3px solid #000;
}

/* 锚点防遮挡 */
h1, h2, h3, h4, h5, h6, section[id] {
  scroll-margin-top: calc(var(--header-height) + 1.5rem);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.15s ease, border-color 0.15s ease;
}
a:hover {
  color: var(--color-primary-hover);
  text-decoration: underline;
}
a:focus-visible, button:focus-visible, summary:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
}

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

/* 容器规范 */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.25rem;
  padding-right: 1.25rem;
}

/* 页眉与导航 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}
.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-main);
  text-decoration: none;
}
.brand-logo svg {
  width: 28px;
  height: 28px;
  fill: var(--color-primary);
}
.site-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}
.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  padding: 0.5rem 0.25rem;
}
.nav-link:hover {
  color: var(--color-primary);
  text-decoration: none;
}
.nav-link.active {
  color: var(--color-primary);
  font-weight: 600;
}
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

/* 按钮规范 (满足 44x44px 触控要求) */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 44px;
  padding: 0.625rem 1.25rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.15s ease-in-out;
  white-space: nowrap;
}
.btn-primary {
  background-color: var(--color-primary);
  color: #ffffff !important;
}
.btn-primary:hover {
  background-color: var(--color-primary-hover);
  text-decoration: none;
  box-shadow: var(--shadow-sm);
}
.btn-outline {
  background-color: transparent;
  border-color: var(--color-border-dark);
  color: var(--color-text-main);
}
.btn-outline:hover {
  background-color: var(--color-surface-hover);
  text-decoration: none;
}
.btn-lg {
  min-height: 48px;
  padding: 0.75rem 1.75rem;
  font-size: 1.05rem;
}
.btn-block {
  width: 100%;
}

/* 主视觉区 (Hero) */
.hero-section {
  padding: 4.5rem 0 3.5rem;
  text-align: center;
  background: radial-gradient(circle at 50% 10%, rgba(37, 99, 235, 0.08) 0%, rgba(248, 250, 252, 0) 70%);
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.85rem;
  font-size: 0.825rem;
  font-weight: 600;
  color: var(--color-tag-text);
  background-color: var(--color-tag);
  border-radius: var(--radius-full);
  margin-bottom: 1.25rem;
}
.hero-title {
  font-size: 2.75rem;
  line-height: 1.2;
  font-weight: 800;
  color: var(--color-text-main);
  letter-spacing: -0.025em;
  margin-bottom: 1.25rem;
}
.hero-title .text-gradient {
  color: var(--color-primary);
}
.hero-subtitle {
  font-size: 1.2rem;
  color: var(--color-text-muted);
  max-width: 720px;
  margin: 0 auto 1.5rem;
  font-weight: 400;
}
.hero-intro {
  font-size: 1rem;
  color: var(--color-text-light);
  max-width: 680px;
  margin: 0 auto 2rem;
  line-height: 1.7;
}
.hero-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}
.hero-trust {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  font-size: 0.875rem;
  color: var(--color-text-light);
  flex-wrap: wrap;
}
.hero-trust span {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}
.hero-trust svg {
  width: 16px;
  height: 16px;
  fill: var(--color-success);
}

/* 区块公用规范 */
.section {
  padding: 4.5rem 0;
}
.section-alt {
  background-color: #ffffff;
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}
.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 3rem;
}
.section-tag {
  font-size: 0.825rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--color-primary);
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
  display: block;
}
.section-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-text-main);
  line-height: 1.3;
  margin-bottom: 0.75rem;
}
.section-desc {
  font-size: 1.05rem;
  color: var(--color-text-muted);
}

/* 核心优势卡片网格 (3图文卡片) */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.feature-card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 2rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.feature-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary-border);
}
.feature-icon-wrapper {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  background-color: var(--color-primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
}
.feature-icon-wrapper svg {
  width: 24px;
  height: 24px;
  fill: var(--color-primary);
}
.feature-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  color: var(--color-text-main);
}
.feature-text {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* 流媒体与AI支持卡片网格 */
.media-ai-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}
.media-card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 2rem;
}
.media-header {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  margin-bottom: 1.25rem;
}
.media-header svg {
  width: 32px;
  height: 32px;
  fill: var(--color-primary);
}
.media-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--color-text-main);
}
.media-desc {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  margin-bottom: 1.5rem;
}
.tags-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.tag-badge {
  display: inline-flex;
  align-items: center;
  padding: 0.4rem 0.8rem;
  font-size: 0.85rem;
  font-weight: 600;
  background-color: #f1f5f9;
  color: #334155;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
}

/* 套餐价格对比表 (可横向滚动容器) */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
  margin-bottom: 2rem;
}
.pricing-card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.pricing-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}
.pricing-card.featured {
  border: 2px solid var(--color-primary);
  box-shadow: var(--shadow-lg);
}
.pricing-badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background-color: var(--color-primary);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-full);
}
.pricing-name {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-text-main);
  margin-bottom: 0.5rem;
}
.pricing-desc {
  font-size: 0.85rem;
  color: var(--color-text-light);
  min-height: 2.5rem;
  margin-bottom: 1rem;
}
.pricing-price {
  display: flex;
  align-items: baseline;
  gap: 0.25rem;
  margin-bottom: 1.5rem;
}
.price-symbol {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-text-main);
}
.price-number {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--color-text-main);
  line-height: 1;
}
.price-unit {
  font-size: 0.875rem;
  color: var(--color-text-light);
}
.pricing-features {
  list-style: none;
  margin: 0 0 2rem;
  flex-grow: 1;
}
.pricing-features li {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
}
.pricing-features svg {
  width: 16px;
  height: 16px;
  fill: var(--color-success);
  flex-shrink: 0;
}

/* 用户真实评价 */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.review-card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.75rem;
}
.review-rating {
  display: flex;
  gap: 0.25rem;
  margin-bottom: 1rem;
  color: #f59e0b;
}
.review-rating svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}
.review-text {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.6;
  margin-bottom: 1.25rem;
  font-style: italic;
}
.review-user {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.user-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
}
.user-info {
  display: flex;
  flex-direction: column;
}
.user-name {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text-main);
}
.user-meta {
  font-size: 0.8rem;
  color: var(--color-text-light);
}

/* FAQ 常见问题 (默认展开 <details open>) */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.faq-item {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}
.faq-summary {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-text-main);
  padding: 1.25rem 1.5rem;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
}
.faq-summary::-webkit-details-marker {
  display: none;
}
.faq-summary::after {
  content: "▾";
  font-size: 1.2rem;
  color: var(--color-text-light);
  transition: transform 0.2s ease;
}
.faq-item[open] .faq-summary::after {
  transform: rotate(180deg);
}
.faq-answer {
  padding: 0 1.5rem 1.25rem;
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  border-top: 1px solid #f1f5f9;
}
.faq-answer p:not(:last-child) {
  margin-bottom: 0.75rem;
}

/* 页脚 (严格保留四个标题外链) */
.site-footer {
  background-color: #0f172a;
  color: #94a3b8;
  padding: 3.5rem 0 2rem;
  margin-top: auto;
  border-top: 1px solid #1e293b;
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 2rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid #1e293b;
}
.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.footer-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: #f8fafc;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.footer-logo svg {
  width: 24px;
  height: 24px;
  fill: #38bdf8;
}
.footer-slogan {
  font-size: 0.875rem;
  color: #64748b;
}
.footer-nav {
  display: flex;
  align-items: center;
  gap: 2rem;
  flex-wrap: wrap;
}
.footer-link {
  color: #cbd5e1;
  font-size: 0.95rem;
  font-weight: 500;
  text-decoration: none;
  padding: 0.5rem 0;
  transition: color 0.15s ease;
}
.footer-link:hover {
  color: #38bdf8;
  text-decoration: underline;
}
.footer-bottom {
  padding-top: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.85rem;
  color: #64748b;
}

/* 文章详情页 / 知识科普页专用样式 */
.article-header {
  padding: 3rem 0 2rem;
  background-color: #ffffff;
  border-bottom: 1px solid var(--color-border);
  text-align: center;
}
.article-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  font-size: 0.875rem;
  color: var(--color-text-light);
  margin-top: 1rem;
  flex-wrap: wrap;
}
.article-content {
  max-width: 820px;
  margin: 3rem auto;
  background: #ffffff;
  padding: 2.5rem 3rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}
.article-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text-main);
  margin: 2rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-border);
}
.article-content h3 {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--color-text-main);
  margin: 1.5rem 0 0.75rem;
}
.article-content p {
  font-size: 1rem;
  line-height: 1.8;
  color: #334155;
  margin-bottom: 1.25rem;
}
.article-content ul, .article-content ol {
  padding-left: 1.5rem;
  margin-bottom: 1.25rem;
  color: #334155;
}
.article-content li {
  margin-bottom: 0.5rem;
  line-height: 1.7;
}
.article-content blockquote {
  background-color: #f8fafc;
  border-left: 4px solid var(--color-primary);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--color-text-muted);
}
.article-cta-box {
  background: linear-gradient(135deg, #eff6ff 0%, #f0fdf4 100%);
  border: 1px solid var(--color-primary-border);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  text-align: center;
  margin: 2.5rem 0;
}
.article-cta-box h3 {
  margin-top: 0;
  font-size: 1.25rem;
  color: var(--color-text-main);
}
.article-cta-box p {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  margin-bottom: 1.25rem;
}

/* 知识科普文章列表卡片网格 */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin: 2.5rem 0;
}
.article-card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.article-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary-border);
}
.article-card-tag {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-primary);
  background-color: var(--color-primary-light);
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-sm);
  align-self: flex-start;
  margin-bottom: 0.75rem;
}
.article-card-title {
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.4;
  color: var(--color-text-main);
  margin-bottom: 0.75rem;
}
.article-card-desc {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  line-height: 1.6;
  flex-grow: 1;
  margin-bottom: 1rem;
}
.article-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--color-text-light);
  border-top: 1px solid #f1f5f9;
  padding-top: 0.75rem;
}

/* 辅助页面 (关于/条款/隐私/网站地图) 布局 */
.page-container {
  max-width: 860px;
  margin: 3rem auto;
  background: #ffffff;
  padding: 2.5rem 3rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}
.page-container h2 {
  font-size: 1.4rem;
  font-weight: 700;
  margin: 1.75rem 0 0.75rem;
  color: var(--color-text-main);
}
.page-container p {
  font-size: 0.95rem;
  color: #334155;
  line-height: 1.75;
  margin-bottom: 1rem;
}
.page-container ul {
  padding-left: 1.5rem;
  margin-bottom: 1.25rem;
}
.page-container li {
  margin-bottom: 0.5rem;
  color: #334155;
  line-height: 1.6;
}

/* 网站地图链接分类列表 */
.sitemap-section {
  margin-bottom: 2rem;
}
.sitemap-section h3 {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-text-main);
  margin-bottom: 0.75rem;
  padding-bottom: 0.25rem;
  border-bottom: 2px solid var(--color-primary-light);
}
.sitemap-links {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
}
.sitemap-links li a {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--color-primary);
  font-size: 0.95rem;
}

/* ==========================================================================
   响应式断点适配 (@media)
   测试宽度标准：360px, 390px, 768px, 1440px
   ========================================================================== */

@media (max-width: 1024px) {
  .features-grid, .articles-grid, .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .hero-title {
    font-size: 2rem;
  }
  .hero-subtitle {
    font-size: 1.05rem;
  }
  .features-grid, .articles-grid, .media-ai-grid, .pricing-grid, .reviews-grid, .sitemap-links {
    grid-template-columns: 1fr;
  }
  .article-content, .page-container {
    padding: 1.5rem 1.25rem;
    margin: 1.5rem auto;
  }
  .site-nav {
    gap: 0.75rem;
  }
  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
  }
  .footer-nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 1.75rem;
  }
  .btn {
    width: 100%;
  }
  .hero-cta {
    flex-direction: column;
    width: 100%;
  }
  .site-header .container {
    padding-left: 0.75rem;
    padding-right: 0.75rem;
  }
  .brand-logo span {
    font-size: 1.1rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}