/* ==========================================================================
   云图机场 (Yuntu Cloud) - 官方网站核心样式表
   技术标准：纯原生 CSS，零外部依赖，极速秒开，响应式与无障碍深度优化
   ========================================================================== */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

  /* 配色系统 (WCAG 4.5:1 高对比度) */
  --bg-primary: #0a0e17;
  --bg-secondary: #111827;
  --bg-tertiary: #1f2937;
  --card-bg: rgba(255, 255, 255, 0.03);
  --card-border: rgba(255, 255, 255, 0.08);
  --card-hover-border: #3b82f6;

  --text-main: #f9fafb;
  --text-muted: #9ca3af;
  --text-sub: #d1d5db;

  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --primary-light: rgba(59, 130, 246, 0.15);
  --accent: #10b981;
  --accent-light: rgba(16, 185, 129, 0.15);
  --warning: #f59e0b;

  --max-width: 1200px;
  --header-height: 72px;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.6);
}

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

html {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-main);
  line-height: 1.6;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

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

/* 键盘无障碍跳过导航 */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  background: var(--primary);
  color: #fff;
  padding: 0.75rem 1.25rem;
  z-index: 9999;
  border-radius: var(--radius-sm);
  font-weight: 600;
  text-decoration: none;
  transition: top 0.2s ease;
}
.skip-link:focus {
  top: 1rem;
}

/* 锚点防遮挡 */
[id] {
  scroll-margin-top: calc(var(--header-height) + 1.5rem);
}

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

/* 链接与排版 */
a {
  color: var(--primary);
  text-decoration: none;
  transition: color 0.2s ease, opacity 0.2s ease;
}
a:hover {
  color: #60a5fa;
  text-decoration: underline;
}
a:focus-visible, button:focus-visible, summary:focus-visible {
  outline: 2px solid #60a5fa;
  outline-offset: 3px;
}

h1, h2, h3, h4 {
  color: #ffffff;
  font-weight: 700;
  line-height: 1.3;
}
h1 { font-size: clamp(1.8rem, 4vw, 2.75rem); }
h2 { font-size: clamp(1.4rem, 3vw, 2rem); margin-bottom: 1rem; }
h3 { font-size: 1.25rem; margin-bottom: 0.5rem; }
p { color: var(--text-sub); margin-bottom: 1rem; }

/* 头部导航栏 */
.site-header {
  position: sticky;
  top: 0;
  width: 100%;
  height: var(--header-height);
  background: rgba(10, 14, 23, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--card-border);
  z-index: 1000;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}
.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: #ffffff;
  font-size: 1.25rem;
  font-weight: 800;
  text-decoration: none;
}
.brand-logo:hover {
  text-decoration: none;
}
.brand-icon {
  width: 32px;
  height: 32px;
  fill: var(--primary);
}
.nav-menu {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 1.5rem;
}
.nav-menu a {
  color: var(--text-sub);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 0.5rem 0.2rem;
  display: inline-block;
  min-height: 44px;
  line-height: 28px;
}
.nav-menu a:hover {
  color: #ffffff;
  text-decoration: none;
}
.nav-cta {
  display: flex;
  align-items: center;
}

/* 按钮规范 (满足移动端 >= 44x44px 点击区域) */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.65rem 1.5rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  text-decoration: none;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.2s ease;
  white-space: nowrap;
}
.btn:hover {
  text-decoration: none;
  transform: translateY(-1px);
}
.btn-primary {
  background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
  color: #ffffff;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}
.btn-primary:hover {
  background: linear-gradient(135deg, #60a5fa 0%, #3b82f6 100%);
  box-shadow: 0 6px 20px rgba(59, 130, 246, 0.5);
}
.btn-secondary {
  background: rgba(255, 255, 255, 0.08);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.15);
}
.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.14);
}
.btn-lg {
  min-height: 48px;
  padding: 0.85rem 2rem;
  font-size: 1.05rem;
}

/* 主视觉区 (Hero) */
.hero-section {
  padding: 4.5rem 0 3.5rem;
  text-align: center;
  background: radial-gradient(circle at 50% 20%, rgba(59, 130, 246, 0.12) 0%, transparent 70%);
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 1rem;
  background: var(--primary-light);
  border: 1px solid rgba(59, 130, 246, 0.3);
  border-radius: 999px;
  color: #93c5fd;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
}
.hero-title {
  margin-bottom: 1.2rem;
  letter-spacing: -0.02em;
}
.hero-title span {
  background: linear-gradient(135deg, #60a5fa 0%, #a78bfa 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.hero-subtitle {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  max-width: 780px;
  margin: 0 auto 1.5rem;
  color: var(--text-sub);
}
.hero-intro {
  font-size: 0.95rem;
  max-width: 700px;
  margin: 0 auto 2rem;
  color: var(--text-muted);
}
.hero-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
}
.hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 1.25rem;
  max-width: 800px;
  margin: 0 auto;
  padding: 1.5rem;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
}
.stat-item {
  text-align: center;
}
.stat-number {
  font-size: 1.6rem;
  font-weight: 800;
  color: #ffffff;
  display: block;
}
.stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* 区块排版 */
.section {
  padding: 4rem 0;
  border-top: 1px solid var(--card-border);
}
.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 3rem;
}
.section-tag {
  color: var(--primary);
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
  display: block;
}

/* 三个核心优势图文卡片 */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.feature-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease, border-color 0.2s ease;
}
.feature-card:hover {
  transform: translateY(-4px);
  border-color: var(--card-hover-border);
}
.feature-icon-wrapper {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  background: var(--primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
}
.feature-icon-wrapper svg {
  width: 28px;
  height: 28px;
  fill: var(--primary);
}

/* 流媒体与 AI 支持图卡 */
.support-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}
.support-card {
  background: linear-gradient(145deg, rgba(255, 255, 255, 0.04) 0%, rgba(255, 255, 255, 0.01) 100%);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 2.25rem;
}
.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1.25rem;
  list-style: none;
}
.tag-item {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  color: var(--text-sub);
}

/* 套餐价格对比表 */
.pricing-section .table-container {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  margin-bottom: 2rem;
}
.pricing-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  min-width: 640px;
}
.pricing-table caption {
  padding: 1rem;
  font-size: 0.9rem;
  color: var(--text-muted);
  text-align: left;
}
.pricing-table th, .pricing-table td {
  padding: 1.25rem 1rem;
  border-bottom: 1px solid var(--card-border);
}
.pricing-table th {
  background: rgba(255, 255, 255, 0.02);
  color: #ffffff;
  font-weight: 600;
  font-size: 0.95rem;
}
.pricing-table tbody tr:hover {
  background: rgba(255, 255, 255, 0.02);
}
.pricing-price {
  font-size: 1.35rem;
  font-weight: 800;
  color: #60a5fa;
}
.pricing-period {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: normal;
}
.plan-badge {
  display: inline-block;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 700;
  background: rgba(16, 185, 129, 0.2);
  color: #34d399;
  margin-left: 0.5rem;
}

/* 用户评价 */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.review-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}
.review-user {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-top: 1rem;
}
.review-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: var(--primary);
  border: 1px solid var(--card-border);
}
.review-meta {
  font-size: 0.85rem;
}
.review-name {
  color: #ffffff;
  font-weight: 600;
}
.review-role {
  color: var(--text-muted);
}
.star-rating {
  color: #fbbf24;
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
}

/* FAQ 常见问题 (details/summary 默认展开) */
.faq-list {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
details.faq-item {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  transition: border-color 0.2s ease;
}
details.faq-item[open] {
  border-color: rgba(59, 130, 246, 0.4);
}
details.faq-item summary {
  font-size: 1.05rem;
  font-weight: 600;
  color: #ffffff;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  min-height: 44px;
}
details.faq-item summary::-webkit-details-marker {
  display: none;
}
details.faq-item summary::after {
  content: "+";
  font-size: 1.4rem;
  color: var(--primary);
  font-weight: 300;
  line-height: 1;
}
details.faq-item[open] summary::after {
  content: "−";
}
.faq-answer {
  padding-top: 1rem;
  color: var(--text-sub);
  font-size: 0.95rem;
  line-height: 1.7;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  margin-top: 0.75rem;
}
.faq-answer p:last-child {
  margin-bottom: 0;
}

/* 页脚 (严格遵守：只有四个标题链接) */
.site-footer {
  background: #070a10;
  border-top: 1px solid var(--card-border);
  padding: 3rem 0 2rem;
  margin-top: auto;
}
.footer-links-grid {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 2.5rem;
  margin-bottom: 2rem;
}
.footer-link-item a {
  color: var(--text-sub);
  font-size: 1.05rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0.5rem 0.5rem;
}
.footer-link-item a:hover {
  color: #ffffff;
  text-decoration: underline;
}
.footer-copyright {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 1.5rem;
}

/* 知识科普与文章页面专属排版 */
.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}
.breadcrumbs a {
  color: var(--text-muted);
}
.breadcrumbs a:hover {
  color: var(--primary);
}
.article-header {
  margin-bottom: 2.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--card-border);
}
.article-meta {
  display: flex;
  gap: 1.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.75rem;
  flex-wrap: wrap;
}
.article-content {
  max-width: 820px;
  margin: 0 auto;
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text-sub);
}
.article-content h2 {
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  color: #ffffff;
  border-left: 4px solid var(--primary);
  padding-left: 0.75rem;
}
.article-content h3 {
  margin-top: 1.75rem;
  margin-bottom: 0.75rem;
  color: #e5e7eb;
}
.article-content ul, .article-content ol {
  margin-left: 1.5rem;
  margin-bottom: 1.5rem;
}
.article-content li {
  margin-bottom: 0.5rem;
}
.article-content blockquote {
  background: rgba(59, 130, 246, 0.08);
  border-left: 4px solid var(--primary);
  padding: 1rem 1.25rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin-bottom: 1.5rem;
  font-style: normal;
}
.article-cta-box {
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.15) 0%, rgba(16, 185, 129, 0.1) 100%);
  border: 1px solid rgba(59, 130, 246, 0.3);
  border-radius: var(--radius-md);
  padding: 2rem;
  text-align: center;
  margin: 3rem 0;
}
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}
.article-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform 0.2s ease, border-color 0.2s ease;
}
.article-card:hover {
  transform: translateY(-3px);
  border-color: var(--card-hover-border);
}
.article-card-title {
  font-size: 1.15rem;
  margin-bottom: 0.75rem;
}
.article-card-title a {
  color: #ffffff;
}
.article-card-title a:hover {
  color: var(--primary);
  text-decoration: none;
}
.article-excerpt {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 1rem;
}

/* 网站地图样式 */
.sitemap-group {
  margin-bottom: 2.5rem;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 1.75rem;
}
.sitemap-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 0.75rem;
  margin-top: 1rem;
}
.sitemap-list li a {
  display: inline-block;
  padding: 0.4rem 0;
  min-height: 44px;
  line-height: 36px;
  font-size: 0.95rem;
}

/* 响应式媒体查询 (@media) */
@media (max-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 64px;
  }
  .nav-menu {
    display: none; /* 移动端精简顶部直达主要操作与知识科普入口 */
  }
  .hero-section {
    padding: 3rem 0 2rem;
  }
  .features-grid, .support-grid, .reviews-grid {
    grid-template-columns: 1fr;
  }
  .footer-links-grid {
    flex-direction: column;
    gap: 1rem;
    align-items: center;
  }
  .hero-actions {
    flex-direction: column;
    width: 100%;
  }
  .btn-lg {
    width: 100%;
  }
}

@media (max-width: 390px) {
  .container {
    padding-left: 1rem;
    padding-right: 1rem;
  }
  .hero-title {
    font-size: 1.65rem;
  }
}

/* 减弱动效偏好 */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}