/* ==========================================
   尔湾云 Ervine Cloud - 全局样式表 (浅色主题 Light Mode)
   纯 CSS3，无依赖，极速加载
   ========================================== */

:root {
  /* 品牌色系 */
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --primary-border: #bfdbfe;
  --accent: #6366f1;
  --accent-light: #e0e7ff;
  --success: #10b981;
  --warning: #f59e0b;

  /* 中性背景色 */
  --bg-body: #f8fafc;
  --bg-surface: #ffffff;
  --bg-subtle: #f1f5f9;
  --bg-glass: rgba(255, 255, 255, 0.85);

  /* 文字颜色 */
  --text-main: #0f172a;
  --text-body: #334155;
  --text-muted: #64748b;
  --text-light: #94a3b8;

  /* 边框与阴影 */
  --border-color: #e2e8f0;
  --border-light: #f1f5f9;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.06), 0 2px 4px -2px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 25px -5px rgba(37, 99, 235, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
  --shadow-hover: 0 20px 30px -10px rgba(37, 99, 235, 0.18);

  /* 圆角 */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;

  /* 动画过渡 */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
  background-color: var(--bg-body);
  color: var(--text-body);
  line-height: 1.6;
  overflow-x: hidden;
}

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

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

/* 通用容器 */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 80px 0;
}

.section-bg-subtle {
  background-color: var(--bg-subtle);
}

/* 标题样式 */
.section-title-wrap {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 56px auto;
}

.section-badge {
  display: inline-block;
  padding: 6px 16px;
  background-color: var(--primary-light);
  color: var(--primary);
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  margin-bottom: 12px;
  border: 1px solid var(--primary-border);
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.25;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--text-muted);
}

/* 按钮通用规范 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  cursor: pointer;
  border: none;
  text-align: center;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: #ffffff !important;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.4);
  color: #ffffff !important;
}

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

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

.btn-lg {
  padding: 16px 36px;
  font-size: 1.125rem;
  border-radius: var(--radius-md);
}

.btn-block {
  width: 100%;
}

/* ==========================================
   头部导航栏 Header
   ========================================== */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--bg-glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: all var(--transition-normal);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-main);
}

.logo-icon {
  width: 38px;
  height: 38px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  font-size: 1.25rem;
  font-weight: 900;
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.25);
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-body);
}

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

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* ==========================================
   Hero 主视觉区
   ========================================== */
.hero {
  padding: 90px 0 80px 0;
  background: radial-gradient(circle at 50% 0%, #eff6ff 0%, var(--bg-body) 70%);
  position: relative;
  overflow: hidden;
}

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

.hero-title {
  font-size: 3.5rem;
  font-weight: 900;
  line-height: 1.15;
  color: var(--text-main);
  margin-bottom: 24px;
  letter-spacing: -0.03em;
}

.hero-title-highlight {
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 40px;
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
}

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

.hero-features-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 32px;
  padding-top: 32px;
  border-top: 1px solid var(--border-color);
  flex-wrap: wrap;
}

.hero-feature-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-body);
}

.hero-feature-icon {
  width: 20px;
  height: 20px;
  color: var(--primary);
}

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

.advantage-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-sm);
}

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

.advantage-icon-box {
  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: 1.5rem;
  margin-bottom: 20px;
}

.advantage-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 12px;
}

.advantage-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ==========================================
   流媒体与 AI 支持 Media & AI
   ========================================== */
.media-ai-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.media-ai-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px;
  box-shadow: var(--shadow-md);
}

.media-ai-card-title {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.tag-item {
  display: flex;
  align-items: center;
  gap: 8px;
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-color);
  padding: 10px 18px;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-main);
  transition: all var(--transition-fast);
}

.tag-item:hover {
  background-color: var(--primary-light);
  border-color: var(--primary-border);
  color: var(--primary);
}

.tag-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--success);
}

/* ==========================================
   套餐价格对比表 Pricing Table
   ========================================== */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  align-items: stretch;
}

.pricing-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-sm);
}

.pricing-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.pricing-card-popular {
  border: 2px solid var(--primary);
  box-shadow: var(--shadow-lg);
}

.popular-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  color: #ffffff;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 4px 16px;
  border-radius: var(--radius-full);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.pricing-name {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 8px;
}

.pricing-desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 24px;
  min-height: 42px;
}

.pricing-price-box {
  margin-bottom: 28px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-color);
}

.pricing-price {
  font-size: 2.5rem;
  font-weight: 900;
  color: var(--text-main);
  line-height: 1;
}

.pricing-currency {
  font-size: 1.25rem;
  font-weight: 700;
  vertical-align: super;
}

.pricing-period {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 500;
}

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

.pricing-feature-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-body);
  margin-bottom: 14px;
}

.pricing-feature-icon {
  width: 18px;
  height: 18px;
  color: var(--success);
  flex-shrink: 0;
}

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

.testimonial-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.testimonial-stars {
  color: var(--warning);
  font-size: 1.1rem;
  margin-bottom: 16px;
}

.testimonial-text {
  font-size: 0.95rem;
  color: var(--text-body);
  line-height: 1.6;
  margin-bottom: 24px;
  font-style: italic;
}

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

.avatar-circle {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary-light) 0%, var(--accent-light) 100%);
  color: var(--primary);
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  border: 1px solid var(--primary-border);
}

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

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

/* ==========================================
   常见问题 FAQ
   ========================================== */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.faq-item {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.faq-item details {
  width: 100%;
}

.faq-summary {
  padding: 20px 24px;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-main);
  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: 1.5rem;
  font-weight: 400;
  color: var(--text-muted);
  transition: transform var(--transition-fast);
}

details[open] .faq-summary::after {
  content: "−";
  color: var(--primary);
}

.faq-content {
  padding: 0 24px 20px 24px;
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.6;
  border-top: 1px solid var(--border-light);
  padding-top: 16px;
}

/* ==========================================
   页脚 Footer（按规范仅保留4个独立标题链接）
   ========================================== */
.footer {
  background-color: var(--bg-surface);
  border-top: 1px solid var(--border-color);
  padding: 48px 0;
  text-align: center;
}

.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 40px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.footer-link {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-main);
  transition: color var(--transition-fast);
  padding: 6px 12px;
}

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

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

/* ==========================================
   子页面专有通用样式 Page Template Styles
   ========================================== */
.page-header {
  padding: 60px 0 40px 0;
  background: radial-gradient(circle at 50% 0%, #eff6ff 0%, var(--bg-body) 80%);
  border-bottom: 1px solid var(--border-color);
  text-align: center;
}

.page-title {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 12px;
}

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

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

.content-card h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-main);
  margin-top: 24px;
  margin-bottom: 12px;
  border-bottom: 2px solid var(--primary-light);
  padding-bottom: 8px;
}

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

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

.content-card ul {
  margin-left: 20px;
  margin-bottom: 16px;
}

.content-card li {
  margin-bottom: 8px;
  color: var(--text-body);
}

/* ==========================================
   响应式媒体查询 @media Responsive (手机端适配)
   ========================================== */
@media (max-width: 992px) {
  .hero-title {
    font-size: 2.75rem;
  }
  .grid-4, .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .grid-3 {
    grid-template-columns: repeat(1, 1fr);
  }
  .media-ai-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .section {
    padding: 50px 0;
  }
  .header-container {
    height: 64px;
  }
  .nav-list {
    display: none; /* 移动端隐藏冗余菜单，保留直接的动作按钮 */
  }
  .hero {
    padding: 50px 0 40px 0;
  }
  .hero-title {
    font-size: 2.1rem;
  }
  .hero-subtitle {
    font-size: 1rem;
  }
  .hero-cta {
    flex-direction: column;
    width: 100%;
  }
  .btn {
    width: 100%;
    min-height: 48px; /* 适合手指点击的热区 */
  }
  .grid-4, .pricing-grid {
    grid-template-columns: 1fr;
  }
  .section-title {
    font-size: 1.75rem;
  }
  .footer-nav {
    flex-direction: column;
    gap: 16px;
  }
  .content-card {
    padding: 24px;
  }
}