/* 魔戒机场 · 暗夜银环版 全局样式表 (V3 高清视觉规范) */
:root {
  --bg-primary: #080D12;
  --bg-secondary: #121820;
  --bg-card: #1A1E29;
  --bg-card-hover: #222836;
  --bg-card-highlight: #262D3D;
  
  --silver-glow: rgba(192, 198, 212, 0.28);
  --silver-bright: #FFFFFF;
  --silver-primary: #C0C6D4;
  --silver-muted: #8E98A8;
  --silver-dark: #323A46;
  
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-medium: rgba(192, 198, 212, 0.24);
  --border-highlight: #D4DEEC;
  
  --accent-badge: #1A2230;
  --accent-badge-text: #DCE5F2;
  
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
  --max-width: 1200px;
  --header-height: 76px;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-full: 9999px;
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

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

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

body {
  min-height: 100vh;
  background-color: var(--bg-primary);
  background-image: 
    radial-gradient(ellipse at 50% -10%, rgba(35, 45, 60, 0.5) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 30%, rgba(20, 26, 36, 0.4) 0%, transparent 50%),
    linear-gradient(180deg, #080D12 0%, #0C1117 100%);
  overflow-x: hidden;
  position: relative;
}

/* 无障碍：跳过主内容链接 */
.skip-link {
  position: absolute;
  top: -100px;
  left: 20px;
  background: var(--silver-bright);
  color: var(--bg-primary);
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  font-weight: 700;
  z-index: 9999;
  text-decoration: none;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 20px;
  outline: 2px solid #5F8AE6;
}

/* 锚点防遮挡 */
[id] {
  scroll-margin-top: calc(var(--header-height) + 24px);
}

/* 排版与链接 */
a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:focus-visible, button:focus-visible, summary:focus-visible {
  outline: 2px solid var(--border-highlight);
  outline-offset: 3px;
}

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

ul, ol {
  list-style: none;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* 顶部导航 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--header-height);
  background: rgba(8, 9, 11, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.brand-logo-link {
  display: flex;
  align-items: center;
  gap: 12px;
  min-height: 44px;
}

.brand-logo-img {
  height: 44px;
  width: auto;
  display: block;
  transition: opacity var(--transition-fast);
}

.brand-logo-img:hover {
  opacity: 0.9;
}

.site-footer .brand-logo-link img {
  height: 38px;
  width: auto;
}

.brand-title-wrap {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-size: 1.15rem;
  font-weight: 800;
  letter-spacing: 0.05em;
  color: var(--silver-bright);
}

.brand-sub {
  font-size: 0.65rem;
  letter-spacing: 0.16em;
  color: var(--silver-muted);
}

.main-nav {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--silver-muted);
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  position: relative;
}

.nav-link:hover, .nav-link.active {
  color: var(--silver-bright);
}

.nav-link::after {
  content: "";
  position: absolute;
  bottom: 8px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--silver-bright);
  transition: width var(--transition-fast);
}

.nav-link:hover::after, .nav-link.active::after {
  width: 100%;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  min-width: 44px;
  padding: 10px 22px;
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all var(--transition-normal);
  text-align: center;
  white-space: nowrap;
}

.btn-silver {
  background: linear-gradient(135deg, #FFFFFF 0%, #E3E9F2 45%, #C2CCDA 100%);
  color: #08090B;
  box-shadow: 0 4px 14px rgba(220, 228, 240, 0.2);
}

.btn-silver:hover {
  background: #FFFFFF;
  box-shadow: 0 6px 20px rgba(255, 255, 255, 0.35);
  transform: translateY(-1px);
}

.btn-secondary {
  background: rgba(26, 32, 42, 0.6);
  border-color: var(--border-medium);
  color: var(--silver-primary);
}

.btn-secondary:hover {
  background: rgba(40, 48, 62, 0.85);
  border-color: var(--border-highlight);
  color: var(--silver-bright);
  transform: translateY(-1px);
}

.mobile-menu-btn {
  display: none;
  background: transparent;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--silver-primary);
  width: 44px;
  height: 44px;
  cursor: pointer;
}

/* Hero 首屏 - V3 暗夜银环版 (写实雪山与发光银环集成背景) */
.hero-section {
  position: relative;
  min-height: 720px;
  padding: 100px 0 120px;
  overflow: hidden;
  border-bottom: 1px solid var(--border-subtle);
  background-color: var(--bg-primary);
  background-image: 
    linear-gradient(90deg, rgba(8, 13, 18, 0.96) 0%, rgba(8, 13, 18, 0.82) 42%, rgba(8, 13, 18, 0.25) 75%, transparent 100%),
    url('../assets/hero/hero-mountain-ring.webp');
  background-position: right center;
  background-size: cover;
  background-repeat: no-repeat;
}

.hero-spacer {
  min-height: 480px;
  display: block;
  pointer-events: none;
}

.hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 48px;
}

.hero-content {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.version-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  color: var(--accent-badge-text);
  width: fit-content;
}

.version-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #A6C2F7;
  box-shadow: 0 0 8px #A6C2F7;
}

.hero-title {
  font-size: clamp(2.4rem, 5vw, 3.8rem);
  font-weight: 900;
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--silver-bright);
}

.hero-title-accent {
  background: linear-gradient(135deg, #FFFFFF 0%, #CCD7E6 40%, #8E99A8 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--silver-primary);
  letter-spacing: 0.02em;
}

.hero-desc {
  font-size: 1.05rem;
  color: var(--silver-muted);
  max-width: 560px;
  line-height: 1.7;
}

.hero-cta-wrap {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  padding-top: 8px;
}

.hero-features-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  padding-top: 16px;
  border-top: 1px solid var(--border-subtle);
}

.strip-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.88rem;
  color: var(--silver-muted);
}

.strip-icon {
  width: 18px;
  height: 18px;
  stroke: var(--silver-bright);
}

/* 核心优势卡片区 */
.section {
  padding: 88px 0;
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 56px;
}

.section-tag {
  font-size: 0.8rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: #9FB2CE;
  margin-bottom: 12px;
  display: inline-block;
  font-weight: 700;
}

.section-title {
  font-size: clamp(1.8rem, 3.2vw, 2.5rem);
  font-weight: 800;
  color: var(--silver-bright);
  line-height: 1.25;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 1rem;
  color: var(--silver-muted);
  line-height: 1.7;
}

.advantages-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.advantage-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 36px 28px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.advantage-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.advantage-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-medium);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.4), 0 0 20px rgba(200, 218, 250, 0.08);
}

.advantage-card:hover::before {
  opacity: 1;
}

.card-icon-box {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-medium);
  display: flex;
  align-items: center;
  justify-content: center;
}

.card-icon-box img, .card-icon-box svg {
  width: 26px;
  height: 26px;
}

.card-title {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--silver-bright);
}

.card-desc {
  font-size: 0.95rem;
  color: var(--silver-muted);
  line-height: 1.68;
}

/* 流媒体与 AI 支持 */
.streaming-section {
  background: rgba(14, 18, 24, 0.6);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.stream-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 16px;
}

.stream-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 24px 16px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  text-align: center;
  transition: all var(--transition-fast);
}

.stream-icon {
  width: 42px;
  height: 42px;
  object-fit: contain;
  margin-bottom: 4px;
  display: block;
}

.stream-card:hover {
  border-color: var(--border-medium);
  background: var(--bg-card-hover);
  transform: translateY(-2px);
}

.stream-name {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--silver-bright);
}

.stream-tag {
  font-size: 0.72rem;
  color: var(--silver-muted);
}

/* 套餐区域 - 排版 E 横向列表风格 */
.pricing-section {
  position: relative;
}

.pricing-notes {
  margin-top: 14px;
  font-size: 0.85rem;
  color: #8E98A8;
}

.pricing-table-wrap {
  width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.pricing-list-e {
  display: flex;
  flex-direction: column;
  gap: 20px;
  width: 100%;
}

.plan-item-e {
  display: grid;
  grid-template-columns: 200px 180px 1fr 180px;
  align-items: center;
  gap: 24px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 28px 32px;
  transition: all var(--transition-normal);
  position: relative;
}

.plan-item-e:hover {
  border-color: var(--border-medium);
  background: var(--bg-card-hover);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
}

.plan-item-e.highlight {
  background: var(--bg-card-highlight);
  border-color: var(--border-highlight);
  box-shadow: 0 0 28px rgba(215, 228, 245, 0.16);
}

.plan-col-title {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.plan-name {
  font-size: 1.28rem;
  font-weight: 800;
  color: var(--silver-bright);
}

.plan-badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: var(--radius-full);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  width: fit-content;
}

.badge-standard {
  background: rgba(255, 255, 255, 0.08);
  color: var(--silver-muted);
}

.badge-hot {
  background: linear-gradient(135deg, #FFFFFF, #D4DEEC);
  color: #08090B;
}

.plan-col-price {
  display: flex;
  flex-direction: column;
}

.price-val {
  font-size: 1.85rem;
  font-weight: 800;
  color: var(--silver-bright);
  line-height: 1.1;
}

.price-sub {
  font-size: 0.78rem;
  color: var(--silver-muted);
  margin-top: 4px;
}

.plan-col-features {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 20px;
}

.feature-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.88rem;
  color: var(--silver-primary);
}

.feature-pill svg {
  width: 14px;
  height: 14px;
  stroke: #A8BCD8;
}

.plan-col-action {
  display: flex;
  justify-content: flex-end;
}

/* 用户体验与真实评价区 */
.reviews-section {
  background: rgba(12, 15, 20, 0.5);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.reviews-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 18px;
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
  position: relative;
}

.review-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-medium);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.45), 0 0 16px rgba(192, 198, 212, 0.08);
}

.review-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}

.review-stars {
  display: inline-flex;
  align-items: center;
  gap: 3px;
  color: #F0F4F9;
}

.star-icon {
  width: 15px;
  height: 15px;
  fill: #D8E2F0;
  filter: drop-shadow(0 0 3px rgba(216, 226, 240, 0.45));
}

.review-score {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--silver-bright);
  margin-left: 4px;
}

.review-tag {
  font-size: 0.72rem;
  color: #9BB2D4;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.08);
  padding: 3px 9px;
  border-radius: var(--radius-sm);
  white-space: nowrap;
}

.review-body {
  font-size: 0.93rem;
  color: var(--silver-primary);
  line-height: 1.72;
  margin: 0;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
}

.author-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: linear-gradient(135deg, #242C38 0%, #151A22 100%);
  border: 1px solid var(--border-medium);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--silver-bright);
  flex-shrink: 0;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.author-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.author-name {
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--silver-bright);
  line-height: 1.2;
}

.author-role {
  font-size: 0.75rem;
  color: var(--silver-muted);
  line-height: 1.2;
}

.review-verified {
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.72rem;
  color: #7E8DA0;
  flex-shrink: 0;
}

.review-verified svg {
  width: 13px;
  height: 13px;
  stroke: #728AA8;
}

/* FAQ 常见问题（原生 details 双列） */
.faq-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

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

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

.faq-question {
  padding: 22px 24px;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--silver-bright);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
  min-height: 44px;
}

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

.faq-icon {
  width: 18px;
  height: 18px;
  stroke: var(--silver-muted);
  transition: transform var(--transition-fast);
  flex-shrink: 0;
}

.faq-item[open] .faq-icon {
  transform: rotate(180deg);
  stroke: var(--silver-bright);
}

.faq-answer {
  padding: 0 24px 22px;
  font-size: 0.94rem;
  color: var(--silver-muted);
  line-height: 1.7;
  border-top: 1px solid rgba(255, 255, 255, 0.04);
  padding-top: 14px;
}

/* 底部 CTA 区域 - 真实地球弧线与太空背景 */
.cta-banner-section {
  min-height: 420px;
  padding: 110px 0 130px;
  position: relative;
  overflow: hidden;
  border-top: 1px solid var(--border-subtle);
  background-color: #06090E;
  background-image: 
    linear-gradient(180deg, rgba(8, 13, 18, 0.95) 0%, rgba(8, 13, 18, 0.45) 45%, rgba(6, 9, 14, 0.75) 85%, #050608 100%),
    url('../assets/earth/earth-horizon.webp');
  background-position: center bottom;
  background-size: cover;
  background-repeat: no-repeat;
}

.cta-banner-card {
  text-align: center;
  max-width: 760px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
  position: relative;
  z-index: 1;
}

.cta-title {
  font-size: clamp(2rem, 3.5vw, 2.8rem);
  font-weight: 800;
  color: var(--silver-bright);
  line-height: 1.2;
  text-shadow: 0 2px 16px rgba(0, 0, 0, 0.6);
}

.cta-desc {
  font-size: 1.05rem;
  color: var(--silver-primary);
  max-width: 580px;
  text-shadow: 0 1px 10px rgba(0, 0, 0, 0.5);
}

/* 页脚 - 严格仅保留四个标题链接 */
.site-footer {
  background: #050608;
  border-top: 1px solid var(--border-subtle);
  padding: 48px 0 36px;
  color: var(--silver-muted);
  font-size: 0.9rem;
}

.footer-content {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.footer-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 24px;
}

.footer-nav {
  display: flex;
  align-items: center;
  gap: 36px;
  flex-wrap: wrap;
}

.footer-link {
  font-weight: 500;
  color: var(--silver-primary);
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  transition: color var(--transition-fast);
}

.footer-link:hover {
  color: var(--silver-bright);
  text-decoration: underline;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.82rem;
  color: #6C7685;
}

/* 通用独立页面布局（关于、条款、隐私、地图、文章） */
.page-header {
  padding: 56px 0 36px;
  border-bottom: 1px solid var(--border-subtle);
  background: rgba(14, 18, 25, 0.4);
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--silver-muted);
  margin-bottom: 16px;
  flex-wrap: wrap;
}

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

.page-title {
  font-size: clamp(2rem, 3.2vw, 2.6rem);
  font-weight: 800;
  color: var(--silver-bright);
  line-height: 1.25;
  margin-bottom: 12px;
}

.page-meta {
  display: flex;
  align-items: center;
  gap: 18px;
  font-size: 0.85rem;
  color: var(--silver-muted);
}

.page-content-wrap {
  padding: 56px 0 80px;
}

.prose {
  max-width: 860px;
  margin: 0 auto;
  font-size: 1.02rem;
  line-height: 1.85;
  color: #D3DCE8;
}

.prose h2 {
  font-size: 1.55rem;
  font-weight: 700;
  color: var(--silver-bright);
  margin: 44px 0 18px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-subtle);
}

.prose h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--silver-primary);
  margin: 32px 0 14px;
}

.prose p {
  margin-bottom: 20px;
}

.prose ul, .prose ol {
  margin: 18px 0 24px 24px;
}

.prose li {
  margin-bottom: 10px;
  list-style: disc;
}

.prose a {
  color: #A9C4F0;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.prose a:hover {
  color: #FFFFFF;
}

.article-faq-wrap {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--border-subtle);
}

.article-nav-strip {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 48px;
  padding: 24px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  flex-wrap: wrap;
  gap: 16px;
}

/* 知识科普目录卡片网格 */
.knowledge-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 36px;
}

.knowledge-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: all var(--transition-normal);
}

.knowledge-card:hover {
  border-color: var(--border-medium);
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
}

.k-tag {
  font-size: 0.75rem;
  color: #9BB2D4;
  font-weight: 700;
  text-transform: uppercase;
}

.k-title {
  font-size: 1.18rem;
  font-weight: 700;
  color: var(--silver-bright);
  line-height: 1.35;
}

.k-desc {
  font-size: 0.9rem;
  color: var(--silver-muted);
  line-height: 1.6;
}

.k-link {
  margin-top: auto;
  font-size: 0.88rem;
  font-weight: 600;
  color: #C0CFE5;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 44px;
}

.k-link:hover {
  color: #FFFFFF;
}

/* 响应式断点适配 */
@media (max-width: 1024px) {
  .hero-section {
    min-height: auto;
    padding: 70px 0 90px;
    background-position: 70% center;
    background-image: 
      linear-gradient(180deg, rgba(8, 13, 18, 0.92) 0%, rgba(8, 13, 18, 0.82) 55%, rgba(8, 13, 18, 0.94) 100%),
      url('../assets/hero/hero-mountain-ring.webp');
  }
  .hero-spacer {
    display: none;
  }
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 40px;
  }
  .hero-content {
    align-items: center;
  }
  .hero-desc {
    margin: 0 auto;
  }
  .hero-cta-wrap {
    justify-content: center;
  }
  .hero-features-strip {
    justify-content: center;
  }
  .advantages-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .stream-grid {
    grid-template-columns: repeat(3, 1fr);
  }
  .plan-item-e {
    grid-template-columns: 1fr 1fr;
    gap: 18px;
  }
  .plan-col-action {
    justify-content: flex-start;
  }
  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .knowledge-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .brand-logo-img {
    height: 38px;
  }
  .hero-section {
    min-height: auto;
    padding: 60px 0 80px;
    background-position: 75% center;
    background-image: 
      linear-gradient(180deg, rgba(8, 13, 18, 0.94) 0%, rgba(8, 13, 18, 0.85) 60%, rgba(8, 13, 18, 0.96) 100%),
      url('../assets/hero/hero-mountain-ring.webp');
  }
  .hero-spacer {
    display: none;
  }
  .cta-banner-section {
    min-height: auto;
    padding: 70px 0 85px;
    background-position: center 80%;
  }
  .main-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: rgba(8, 13, 18, 0.98);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-subtle);
    padding: 24px;
    display: none;
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }
  .main-nav.open {
    display: flex;
  }
  .nav-list {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
    width: 100%;
  }
  .nav-link {
    width: 100%;
  }
  .mobile-menu-btn {
    display: flex;
    align-items: center;
    justify-content: center;
  }
  .advantages-grid {
    grid-template-columns: 1fr;
  }
  .stream-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .plan-item-e {
    grid-template-columns: 1fr;
    gap: 16px;
    padding: 22px 20px;
  }
  .faq-grid {
    grid-template-columns: 1fr;
  }
  .reviews-grid {
    grid-template-columns: 1fr;
  }
  .knowledge-grid {
    grid-template-columns: 1fr;
  }
  .footer-top {
    flex-direction: column;
    align-items: flex-start;
  }
  .footer-nav {
    gap: 20px;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 2.1rem;
  }
  .hero-subtitle {
    font-size: 1.05rem;
  }
  .hero-desc {
    font-size: 0.95rem;
  }
  .hero-cta-wrap {
    flex-direction: column;
    width: 100%;
  }
  .hero-cta-wrap .btn {
    width: 100%;
  }
  .stream-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@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;
  }
}