/* ==========================================================================
   龙猫云官网 - 原生极简高性能样式库 (Zero JS Framework, Instant Load)
   ========================================================================== */

:root {
  --bg-primary: #0b0f19;
  --bg-secondary: #111827;
  --bg-card: #162032;
  --bg-card-hover: #1e293b;
  --border-color: #273549;
  --border-highlight: #38bdf8;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --primary: #38bdf8;
  --primary-glow: rgba(56, 189, 248, 0.25);
  --primary-hover: #0284c7;
  --accent: #6366f1;
  --accent-glow: rgba(99, 102, 241, 0.25);
  --success: #10b981;
  --warning: #f59e0b;
  --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;
  --container-max: 1200px;
  --border-radius-sm: 8px;
  --border-radius-md: 12px;
  --border-radius-lg: 18px;
  --transition-fast: 0.2s ease;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 20px rgba(56, 189, 248, 0.15);
}

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

html {
  font-family: var(--font-stack);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-main);
  background-color: var(--bg-primary);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  position: relative;
  background: radial-gradient(circle at 50% 0%, #152238 0%, var(--bg-primary) 70%);
}

/* 键盘可访问性：跳过导航链接 */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  background: var(--primary);
  color: #000;
  padding: 0.75rem 1.25rem;
  font-weight: 700;
  border-radius: var(--border-radius-sm);
  z-index: 9999;
  text-decoration: none;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 1rem;
  outline: 3px solid #fff;
}

/* 焦点指示器规范 */
:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 3px;
}

/* 布局容器 */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

/* 锚点滑动位移修复（避免被固定页眉遮挡） */
section, [id] {
  scroll-margin-top: 90px;
}

/* 页面排版 */
h1, h2, h3, h4 {
  color: #ffffff;
  font-weight: 700;
  line-height: 1.3;
}

h1 { font-size: 2.25rem; margin-bottom: 1.25rem; }
h2 { font-size: 1.85rem; margin-bottom: 1rem; text-align: center; }
h3 { font-size: 1.35rem; margin-bottom: 0.75rem; }
p { margin-bottom: 1rem; color: var(--text-muted); }
a { color: var(--primary); text-decoration: none; transition: color var(--transition-fast); }
a:hover { color: #bae6fd; text-decoration: underline; }
ul, ol { margin-left: 1.5rem; margin-bottom: 1rem; color: var(--text-muted); }
li { margin-bottom: 0.5rem; }

/* 头部导航栏 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(11, 15, 25, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 1rem 0;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.35rem;
  font-weight: 800;
  color: #ffffff;
  text-decoration: none;
}

.brand-logo:hover {
  text-decoration: none;
  color: var(--primary);
}

.logo-badge {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #ffffff;
  padding: 0.25rem 0.6rem;
  border-radius: var(--border-radius-sm);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.5px;
}

.site-nav ul {
  display: flex;
  align-items: center;
  list-style: none;
  margin: 0;
  gap: 1.5rem;
}

.site-nav a {
  color: var(--text-main);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.5rem 0.25rem;
  position: relative;
}

.site-nav a:hover {
  color: var(--primary);
  text-decoration: none;
}

.nav-cta-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 1.25rem;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #ffffff !important;
  font-weight: 700;
  font-size: 0.95rem;
  border-radius: var(--border-radius-md);
  text-decoration: none !important;
  box-shadow: 0 4px 14px var(--primary-glow);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.nav-cta-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px var(--primary-glow);
}

/* 按钮通用规范 (触摸区域 >= 44x44px) */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  min-width: 140px;
  padding: 0.75rem 1.75rem;
  font-size: 1rem;
  font-weight: 700;
  border-radius: var(--border-radius-md);
  cursor: pointer;
  text-decoration: none;
  border: 1px solid transparent;
  transition: all var(--transition-fast);
  text-align: center;
}

.btn:hover {
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: #ffffff;
  box-shadow: 0 6px 18px var(--primary-glow);
}

.btn-primary:hover {
  color: #ffffff;
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(56, 189, 248, 0.4);
}

.btn-secondary {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-main);
}

.btn-secondary:hover {
  background-color: var(--bg-card-hover);
  border-color: var(--primary);
  color: var(--primary);
}

/* 主视觉区 (Hero Section) */
.hero-section {
  padding: 4.5rem 0 3.5rem;
  text-align: center;
  position: relative;
}

.hero-tagline {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.3);
  color: var(--primary);
  padding: 0.4rem 1rem;
  border-radius: 9999px;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 900;
  letter-spacing: -0.5px;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
  margin-bottom: 1.25rem;
}

.hero-title .highlight {
  background: linear-gradient(135deg, #38bdf8, #818cf8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 720px;
  margin: 0 auto 2rem;
  line-height: 1.7;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
}

.hero-trust-bar {
  display: flex;
  justify-content: center;
  gap: 2rem;
  flex-wrap: wrap;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
  max-width: 800px;
  margin: 0 auto;
}

.trust-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
}

.trust-icon {
  width: 18px;
  height: 18px;
  fill: var(--primary);
}

/* 区块公共样式 */
.section-padding {
  padding: 4.5rem 0;
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 3rem;
}

.section-tag {
  color: var(--primary);
  font-weight: 700;
  font-size: 0.85rem;
  letter-spacing: 1px;
  text-transform: uppercase;
  margin-bottom: 0.5rem;
  display: block;
}

.section-desc {
  color: var(--text-muted);
  font-size: 1.05rem;
}

/* 核心优势卡片 (3 Cards) */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.75rem;
}

.feature-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 2.25rem 1.75rem;
  transition: transform var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
  position: relative;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-highlight);
  box-shadow: var(--shadow-glow);
}

.feature-icon-wrapper {
  width: 56px;
  height: 56px;
  border-radius: var(--border-radius-md);
  background: rgba(56, 189, 248, 0.12);
  border: 1px solid rgba(56, 189, 248, 0.25);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
}

.feature-icon {
  width: 28px;
  height: 28px;
  fill: var(--primary);
}

.feature-card h3 {
  color: #ffffff;
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
  margin: 0;
}

/* 流媒体与 AI 支持图卡 */
.media-ai-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.media-ai-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 2.5rem;
  position: relative;
  overflow: hidden;
}

.media-ai-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
}

.media-badge-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 1.5rem 0 1rem;
}

.media-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 0.4rem 0.9rem;
  border-radius: 9999px;
  font-size: 0.85rem;
  color: var(--text-main);
  font-weight: 500;
}

.media-badge svg {
  width: 14px;
  height: 14px;
  fill: var(--success);
}

/* 价格对比表 */
.pricing-section {
  background-color: rgba(17, 24, 39, 0.5);
}

.table-container {
  width: 100%;
  overflow-x: auto;
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--border-color);
  background-color: var(--bg-card);
  box-shadow: var(--shadow-md);
  margin-bottom: 2rem;
  -webkit-overflow-scrolling: touch;
}

.pricing-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  min-width: 640px;
}

.pricing-table caption {
  caption-side: top;
  font-size: 0.9rem;
  color: var(--text-dim);
  text-align: right;
  padding: 0.75rem 1rem 0;
}

.pricing-table th, .pricing-table td {
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.pricing-table thead th {
  background-color: var(--bg-secondary);
  color: #ffffff;
  font-weight: 700;
  font-size: 1rem;
}

.pricing-table tbody tr:hover {
  background-color: rgba(255, 255, 255, 0.02);
}

.pricing-table tbody tr:last-child td {
  border-bottom: none;
}

.plan-name {
  font-weight: 700;
  color: #ffffff;
  font-size: 1.1rem;
  display: block;
}

.plan-tag {
  display: inline-block;
  font-size: 0.75rem;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  background-color: rgba(56, 189, 248, 0.2);
  color: var(--primary);
  margin-top: 0.25rem;
}

.price-text {
  font-size: 1.5rem;
  font-weight: 800;
  color: #ffffff;
}

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

.pricing-cards-mobile {
  display: none;
}

/* 用户评价 (Testimonials) */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.75rem;
}

.review-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 2rem 1.75rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.review-stars {
  color: #fbbf24;
  margin-bottom: 1rem;
  font-size: 1.1rem;
  letter-spacing: 2px;
}

.review-content {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
  margin-bottom: 1.5rem;
  font-style: italic;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.author-avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
}

.author-info h4 {
  font-size: 0.95rem;
  margin: 0;
  color: #ffffff;
}

.author-info span {
  font-size: 0.8rem;
  color: var(--text-dim);
}

/* 常见问题 (FAQ: 默认展开 details/summary) */
.faq-list {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-item {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-md);
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.faq-item[open] {
  border-color: rgba(56, 189, 248, 0.4);
}

.faq-question {
  padding: 1.25rem 1.5rem;
  font-weight: 700;
  color: #ffffff;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  list-style: none;
  font-size: 1.05rem;
  user-select: none;
}

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

.faq-question::after {
  content: "▾";
  font-size: 1.2rem;
  color: var(--primary);
  transition: transform var(--transition-fast);
}

.faq-item[open] .faq-question::after {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 1.5rem 1.25rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  margin-top: 0.5rem;
  padding-top: 1rem;
}

.faq-answer a {
  color: var(--primary);
  text-decoration: underline;
}

/* 底部页脚 (Footer: 严格仅保留4个标题) */
.site-footer {
  margin-top: auto;
  background-color: #080c14;
  border-top: 1px solid var(--border-color);
  padding: 3rem 0 2rem;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 2.5rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}

.footer-nav a {
  color: var(--text-muted);
  font-size: 1rem;
  font-weight: 500;
  transition: color var(--transition-fast);
  padding: 0.5rem 0.75rem;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

.footer-nav a:hover {
  color: var(--primary);
  text-decoration: none;
}

.footer-bottom {
  text-align: center;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-bottom p {
  color: var(--text-dim);
  font-size: 0.85rem;
  margin: 0;
}

/* 知识科普与内页专属样式 */
.article-header {
  padding: 3.5rem 0 2rem;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 2.5rem;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-dim);
  margin-bottom: 1.25rem;
}

.breadcrumb a {
  color: var(--text-muted);
}

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

.article-meta {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  color: var(--text-dim);
  font-size: 0.9rem;
  margin-top: 1rem;
}

.article-body {
  max-width: 840px;
  margin: 0 auto;
  font-size: 1.05rem;
  line-height: 1.85;
}

.article-body h2 {
  font-size: 1.5rem;
  margin: 2.5rem 0 1rem;
  text-align: left;
  border-left: 4px solid var(--primary);
  padding-left: 0.75rem;
}

.article-body h3 {
  font-size: 1.25rem;
  margin: 1.75rem 0 0.75rem;
}

.article-body p {
  margin-bottom: 1.25rem;
  color: #cbd5e1;
}

.article-body blockquote {
  border-left: 4px solid var(--accent);
  background-color: var(--bg-card);
  padding: 1rem 1.25rem;
  border-radius: 0 var(--border-radius-sm) var(--border-radius-sm) 0;
  margin: 1.5rem 0;
  color: var(--text-main);
  font-style: italic;
}

.article-body img {
  max-width: 100%;
  height: auto;
  border-radius: var(--border-radius-md);
  margin: 1.5rem 0;
}

.article-cta-box {
  background: linear-gradient(135deg, rgba(56, 189, 248, 0.1), rgba(99, 102, 241, 0.1));
  border: 1px solid var(--border-highlight);
  border-radius: var(--border-radius-lg);
  padding: 2rem;
  text-align: center;
  margin: 3rem 0;
}

.article-cta-box h3 {
  color: #ffffff;
  margin-bottom: 0.5rem;
}

/* 知识中心索引列表 */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.75rem;
}

.article-summary-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform var(--transition-fast), border-color var(--transition-fast);
}

.article-summary-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-highlight);
}

.article-summary-card h3 {
  font-size: 1.15rem;
  line-height: 1.4;
  margin-bottom: 0.75rem;
}

.article-summary-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  flex-grow: 1;
  margin-bottom: 1.25rem;
}

.article-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-dim);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 0.75rem;
}

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

@media (max-width: 768px) {
  h1 { font-size: 1.85rem; }
  h2 { font-size: 1.5rem; }
  
  .site-header {
    padding: 0.75rem 0;
  }

  .site-nav {
    display: none; /* 移动端精简模式，保障纯HTML无JS下的极简体验 */
  }

  .hero-section {
    padding: 3rem 0 2rem;
  }

  .features-grid, .media-ai-grid, .reviews-grid, .articles-grid {
    grid-template-columns: 1fr;
    gap: 1.25rem;
  }

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

  .hero-cta-group .btn {
    width: 100%;
  }

  .footer-nav {
    flex-direction: column;
    gap: 1rem;
  }

  .pricing-table th, .pricing-table td {
    padding: 1rem 0.75rem;
  }
}

@media (max-width: 480px) {
  .container {
    padding-left: 1rem;
    padding-right: 1rem;
  }

  .brand-logo {
    font-size: 1.15rem;
  }

  .feature-card, .media-ai-card, .review-card {
    padding: 1.5rem 1.25rem;
  }

  .faq-question {
    padding: 1rem 1.25rem;
    font-size: 0.95rem;
  }

  .faq-answer {
    padding: 0 1.25rem 1rem;
  }
}

/* 无障碍用户偏好处理 */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}