/* ==========================================================================
   悠兔云 (Youtu Cloud) - Botanical 植物美学原生样式表
   零重型外部框架依赖 | 100% 原生 CSS | 极速秒开 | 无障碍合规
   ========================================================================== */

/* --------------------------------------------------------------------------
   设计系统权威 Token 声明 (Botanical Design System)
   -------------------------------------------------------------------------- */
:root {
  --dp-color-ground: #f5efdf;
  --dp-color-ink: #1e382c;
  --dp-color-panel: #e0e5d3;
  --dp-color-warm-field: #e6cbb8;
  --dp-color-accent: #895440;
  --dp-color-rule: #d4d0bd;
  --dp-color-ornament-line: #b5baa4;
  --dp-color-field-line: #697961;

  --dp-typography-display: "Botanical Garamond", "EB Garamond", Garamond, Georgia, "Times New Roman", "Source Han Serif CN", "Songti SC", serif;
  --dp-typography-reading: "Botanical Instrument", "Instrument Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  
  --dp-typography-body: 16px;
  --dp-typography-metadata: 13px;
  --dp-typography-label: 12px;
  --dp-typography-compact-leading: 1.5;
  --dp-typography-reading-leading: 1.7;
  --dp-typography-label-tracking: 0.12em;

  --dp-spacing-panel-inline: max(30px, 4.2cqw);
  --dp-radius-panel: 34px;
  --dp-radius-panel-narrow: 27px;
  --dp-radius-round: 50%;
  --dp-radius-button: 9999px;
  --dp-border-hairline: 1px;
  --dp-motion-interaction: 0.35s;
  --dp-motion-easing: ease;

  --dp-shadow-soft: 0 10px 30px rgba(30, 56, 44, 0.05);
  --dp-shadow-lift: 0 14px 34px rgba(30, 56, 44, 0.12);
}

/* --------------------------------------------------------------------------
   基础重置与无障碍保障
   -------------------------------------------------------------------------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  background-color: var(--dp-color-ground);
  color: var(--dp-color-ink);
}

body {
  font-family: var(--dp-typography-reading);
  font-size: var(--dp-typography-body);
  line-height: var(--dp-typography-reading-leading);
  background-color: var(--dp-color-ground);
  color: var(--dp-color-ink);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

/* 键盘焦点指示器 */
:focus-visible {
  outline: 2px solid var(--dp-color-accent);
  outline-offset: 3px;
}

/* 跳过内容链接 */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1.5rem;
  background: var(--dp-color-accent);
  color: #ffffff;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  font-size: var(--dp-typography-metadata);
  border-radius: var(--dp-radius-button);
  z-index: 9999;
  text-decoration: none;
  transition: top var(--dp-motion-interaction) var(--dp-motion-easing);
}

.skip-link:focus {
  top: 1.5rem;
}

/* 锚点滚动留白 */
[id] {
  scroll-margin-top: 96px;
}

/* --------------------------------------------------------------------------
   排版与标题规范
   -------------------------------------------------------------------------- */
h1, h2, h3, h4, .font-serif {
  font-family: var(--dp-typography-display);
  font-weight: 700;
  color: var(--dp-color-ink);
  line-height: 1.25;
}

p {
  color: var(--dp-color-ink);
  opacity: 0.92;
}

a {
  color: inherit;
  text-decoration: none;
}

.text-accent {
  color: var(--dp-color-accent);
}

.text-italic {
  font-style: italic;
}

.label-tracked {
  font-family: var(--dp-typography-reading);
  font-size: var(--dp-typography-label);
  letter-spacing: var(--dp-typography-label-tracking);
  text-transform: uppercase;
  font-weight: 600;
  color: var(--dp-color-accent);
}

/* --------------------------------------------------------------------------
   网格与通用容器
   -------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section-wrapper {
  padding: 5rem 0;
  position: relative;
}

.section-header {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 3.5rem auto;
}

.section-title {
  font-size: clamp(2rem, 3.5vw, 2.75rem);
  margin-top: 0.75rem;
  margin-bottom: 1rem;
  letter-spacing: -0.01em;
}

.section-subtitle {
  font-size: 1.0625rem;
  line-height: 1.6;
  opacity: 0.85;
}

/* 装饰性徽标 Pill */
.section-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 1rem;
  background-color: var(--dp-color-panel);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  border-radius: var(--dp-radius-button);
  font-size: var(--dp-typography-label);
  font-weight: 600;
  letter-spacing: var(--dp-typography-label-tracking);
  color: var(--dp-color-accent);
  text-transform: uppercase;
}

/* --------------------------------------------------------------------------
   页眉导航 (Site Header)
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: rgba(245, 239, 223, 0.94);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: var(--dp-border-hairline) solid var(--dp-color-rule);
  padding: 0.85rem 0;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  font-family: var(--dp-typography-display);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--dp-color-ink);
  letter-spacing: -0.02em;
}

.brand-emblem {
  width: 32px;
  height: 32px;
  background-color: var(--dp-color-panel);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  border-radius: var(--dp-radius-round);
  display: flex;
  align-items: center;
  justify-content: center;
}

.nav-menu {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 2rem;
}

.nav-link {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--dp-color-ink);
  opacity: 0.82;
  transition: opacity var(--dp-motion-interaction), color var(--dp-motion-interaction);
  position: relative;
  padding: 0.25rem 0;
}

.nav-link:hover {
  opacity: 1;
  color: var(--dp-color-accent);
}

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--dp-color-accent);
  border-radius: 2px;
}

/* 知识科普专栏独立标签高亮 */
.nav-link-special {
  background-color: var(--dp-color-panel);
  padding: 0.35rem 0.85rem;
  border-radius: var(--dp-radius-button);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  opacity: 1;
  color: var(--dp-color-ink);
}

.nav-link-special:hover {
  background-color: var(--dp-color-warm-field);
  color: var(--dp-color-accent);
}

/* --------------------------------------------------------------------------
   按钮体系 (Botanical Buttons)
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.85rem 1.85rem;
  font-family: var(--dp-typography-reading);
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--dp-radius-button);
  border: var(--dp-border-hairline) solid transparent;
  cursor: pointer;
  transition: all var(--dp-motion-interaction) var(--dp-motion-easing);
  min-height: 46px;
  min-width: 44px;
  text-align: center;
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--dp-color-ink);
  color: var(--dp-color-ground);
  border-color: var(--dp-color-ink);
  box-shadow: 0 4px 14px rgba(30, 56, 44, 0.15);
}

.btn-primary:hover {
  background-color: var(--dp-color-accent);
  border-color: var(--dp-color-accent);
  color: #ffffff;
  transform: translateY(-2px);
  box-shadow: var(--dp-shadow-lift);
}

.btn-secondary {
  background-color: var(--dp-color-panel);
  color: var(--dp-color-ink);
  border-color: var(--dp-color-ornament-line);
}

.btn-secondary:hover {
  background-color: var(--dp-color-warm-field);
  border-color: var(--dp-color-accent);
  color: var(--dp-color-accent);
  transform: translateY(-2px);
}

.btn-sm {
  padding: 0.55rem 1.25rem;
  font-size: 0.875rem;
  min-height: 40px;
}

.btn-text {
  background: transparent;
  color: var(--dp-color-accent);
  padding: 0.5rem 0.25rem;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.btn-text:hover {
  color: var(--dp-color-ink);
}

/* --------------------------------------------------------------------------
   主视觉区 (Hero Section)
   -------------------------------------------------------------------------- */
.hero-section {
  padding: 4.5rem 0 5.5rem 0;
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 3.5rem;
}

.hero-content {
  display: flex;
  flex-direction: column;
  gap: 1.35rem;
}

.hero-headline {
  font-size: clamp(2.35rem, 4.6vw, 3.85rem);
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--dp-color-ink);
}

.hero-subhead {
  font-size: 1.2rem;
  line-height: 1.5;
  color: var(--dp-color-accent);
  font-weight: 500;
}

.hero-intro {
  font-size: 1.0625rem;
  line-height: 1.7;
  opacity: 0.88;
  max-width: 580px;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  flex-wrap: wrap;
  margin-top: 0.75rem;
}

.hero-trust-row {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  margin-top: 1rem;
  padding-top: 1.25rem;
  border-top: var(--dp-border-hairline) solid var(--dp-color-rule);
  font-size: var(--dp-typography-metadata);
  color: var(--dp-color-ink);
  opacity: 0.85;
}

.trust-item {
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

/* 右侧拱形 Botanical 视觉面板 */
.hero-visual-wrap {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-arch-card {
  width: 100%;
  max-width: 420px;
  background-color: var(--dp-color-panel);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  border-radius: 210px 210px var(--dp-radius-panel) var(--dp-radius-panel);
  padding: 3.25rem 2.25rem 2.75rem 2.25rem;
  box-shadow: var(--dp-shadow-soft);
  position: relative;
  text-align: center;
}

.hero-arch-inner {
  border: var(--dp-border-hairline) dashed var(--dp-color-field-line);
  border-radius: 190px 190px calc(var(--dp-radius-panel) - 8px) calc(var(--dp-radius-panel) - 8px);
  padding: 2.5rem 1.5rem;
  background-color: rgba(245, 239, 223, 0.45);
}

.hero-emblem-large {
  width: 100px;
  height: 100px;
  margin: 0 auto 1.5rem auto;
  background-color: var(--dp-color-ground);
  border: var(--dp-border-hairline) solid var(--dp-color-rule);
  border-radius: var(--dp-radius-round);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(30, 56, 44, 0.06);
}

.hero-arch-title {
  font-size: 1.45rem;
  margin-bottom: 0.5rem;
}

.hero-arch-desc {
  font-size: 0.875rem;
  line-height: 1.6;
  opacity: 0.82;
  margin-bottom: 1.5rem;
}

.hero-badge-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  text-align: left;
}

.hero-badge-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  background-color: var(--dp-color-ground);
  padding: 0.65rem 1rem;
  border-radius: 14px;
  border: var(--dp-border-hairline) solid var(--dp-color-rule);
  font-size: 0.875rem;
  font-weight: 500;
}

/* 底部重叠小圆形装饰徽章 */
.hero-overlap-badge {
  position: absolute;
  bottom: -20px;
  left: 20px;
  width: 86px;
  height: 86px;
  background-color: var(--dp-color-warm-field);
  border: 2px solid var(--dp-color-accent);
  border-radius: var(--dp-radius-round);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: 0 6px 16px rgba(137, 84, 64, 0.2);
  z-index: 2;
}

.hero-overlap-badge span:first-child {
  font-family: var(--dp-typography-display);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--dp-color-accent);
  line-height: 1;
}

.hero-overlap-badge span:last-child {
  font-size: 0.6875rem;
  font-weight: 600;
  color: var(--dp-color-ink);
  letter-spacing: 0.05em;
  margin-top: 2px;
}

/* --------------------------------------------------------------------------
   产品核心优势介绍 (3个图文卡片)
   -------------------------------------------------------------------------- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.feature-card {
  background-color: var(--dp-color-panel);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  border-radius: var(--dp-radius-panel);
  padding: 2.5rem 2rem;
  display: flex;
  flex-direction: column;
  transition: transform var(--dp-motion-interaction) var(--dp-motion-easing), box-shadow var(--dp-motion-interaction) var(--dp-motion-easing);
  position: relative;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--dp-shadow-soft);
}

.feature-icon-wrap {
  width: 58px;
  height: 58px;
  border-radius: 18px;
  background-color: var(--dp-color-ground);
  border: var(--dp-border-hairline) solid var(--dp-color-rule);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
}

.feature-title {
  font-size: 1.35rem;
  margin-bottom: 0.75rem;
  color: var(--dp-color-ink);
}

.feature-desc {
  font-size: 0.9375rem;
  line-height: 1.65;
  opacity: 0.85;
  flex-grow: 1;
}

.feature-points {
  margin-top: 1.25rem;
  padding-top: 1rem;
  border-top: var(--dp-border-hairline) solid var(--dp-color-rule);
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  font-size: 0.875rem;
  font-weight: 500;
}

.feature-points li {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* --------------------------------------------------------------------------
   流媒体与 AI 支持图卡 (Streaming & AI Support)
   -------------------------------------------------------------------------- */
.stream-ai-section {
  background-color: var(--dp-color-warm-field);
  border-radius: var(--dp-radius-panel);
  padding: 4rem var(--dp-spacing-panel-inline);
  margin: 2rem 0;
  border: var(--dp-border-hairline) solid var(--dp-color-rule);
}

.stream-ai-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2.5rem;
  margin-top: 2.5rem;
}

.stream-card {
  background-color: var(--dp-color-ground);
  border: var(--dp-border-hairline) solid var(--dp-color-rule);
  border-radius: var(--dp-radius-panel-narrow);
  padding: 2.25rem 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.stream-card-header {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.stream-card-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--dp-radius-round);
  background-color: var(--dp-color-panel);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  display: flex;
  align-items: center;
  justify-content: center;
}

.stream-badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
}

.stream-tag {
  background-color: var(--dp-color-panel);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  padding: 0.4rem 0.85rem;
  border-radius: var(--dp-radius-button);
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--dp-color-ink);
}

/* --------------------------------------------------------------------------
   套餐价格对比表 (Pricing Table)
   -------------------------------------------------------------------------- */
.pricing-section {
  padding: 5rem 0;
}

.pricing-table-container {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  background-color: var(--dp-color-panel);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  border-radius: var(--dp-radius-panel);
  box-shadow: var(--dp-shadow-soft);
  padding: 2rem;
}

.pricing-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  min-width: 680px;
}

.pricing-table caption {
  font-size: var(--dp-typography-metadata);
  color: var(--dp-color-accent);
  text-align: left;
  margin-bottom: 1.25rem;
  font-weight: 600;
  letter-spacing: var(--dp-typography-label-tracking);
  text-transform: uppercase;
}

.pricing-table th,
.pricing-table td {
  padding: 1.25rem 1.2rem;
  border-bottom: var(--dp-border-hairline) solid var(--dp-color-rule);
  vertical-align: middle;
}

.pricing-table th {
  font-family: var(--dp-typography-reading);
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--dp-color-ink);
  opacity: 0.85;
}

.pricing-table tbody tr {
  transition: background-color var(--dp-motion-interaction);
}

.pricing-table tbody tr:hover {
  background-color: rgba(245, 239, 223, 0.5);
}

/* 特别推荐的高亮套餐行 */
.pricing-table tbody tr.featured-row {
  background-color: var(--dp-color-ground);
  outline: 2px solid var(--dp-color-ink);
  border-radius: 12px;
}

.pricing-tier-name {
  font-family: var(--dp-typography-display);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--dp-color-ink);
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.featured-pill {
  font-family: var(--dp-typography-reading);
  font-size: 0.6875rem;
  font-weight: 700;
  padding: 0.2rem 0.55rem;
  background-color: var(--dp-color-accent);
  color: #ffffff;
  border-radius: var(--dp-radius-button);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.pricing-price {
  font-family: var(--dp-typography-display);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--dp-color-accent);
}

.pricing-price small {
  font-family: var(--dp-typography-reading);
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--dp-color-ink);
  opacity: 0.75;
}

/* --------------------------------------------------------------------------
   用户真实口碑评价 (Testimonials)
   -------------------------------------------------------------------------- */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}

.review-card {
  background-color: var(--dp-color-panel);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  border-radius: var(--dp-radius-panel-narrow);
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 1.25rem;
  position: relative;
}

.review-quote-mark {
  font-family: var(--dp-typography-display);
  font-size: 3rem;
  line-height: 1;
  color: var(--dp-color-accent);
  opacity: 0.6;
  margin-bottom: -1rem;
}

.review-text {
  font-size: 0.9375rem;
  line-height: 1.6;
  opacity: 0.9;
  font-style: italic;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  border-top: var(--dp-border-hairline) solid var(--dp-color-rule);
  padding-top: 1rem;
}

.review-avatar {
  width: 40px;
  height: 40px;
  border-radius: var(--dp-radius-round);
  background-color: var(--dp-color-warm-field);
  border: var(--dp-border-hairline) solid var(--dp-color-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.875rem;
  color: var(--dp-color-accent);
}

.review-meta h4 {
  font-size: 0.9375rem;
  margin-bottom: 0.15rem;
}

.review-meta p {
  font-size: var(--dp-typography-metadata);
  opacity: 0.7;
}

/* --------------------------------------------------------------------------
   常见问题解答 (FAQ Native Disclosures)
   -------------------------------------------------------------------------- */
.faq-section {
  padding: 5rem 0;
}

.faq-list {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-item {
  background-color: var(--dp-color-panel);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  border-radius: 20px;
  padding: 0;
  overflow: hidden;
  transition: all var(--dp-motion-interaction);
}

.faq-item[open] {
  background-color: var(--dp-color-panel);
  border-color: var(--dp-color-field-line);
}

.faq-summary {
  padding: 1.35rem 1.75rem;
  font-family: var(--dp-typography-display);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--dp-color-ink);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  user-select: none;
}

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

.faq-icon-tag {
  width: 28px;
  height: 28px;
  border-radius: var(--dp-radius-round);
  background-color: var(--dp-color-ground);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--dp-color-accent);
  transition: transform var(--dp-motion-interaction);
  flex-shrink: 0;
}

.faq-item[open] .faq-icon-tag {
  transform: rotate(45deg);
  background-color: var(--dp-color-warm-field);
}

.faq-body {
  padding: 0 1.75rem 1.5rem 1.75rem;
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--dp-color-ink);
  opacity: 0.88;
  border-top: var(--dp-border-hairline) solid var(--dp-color-rule);
  padding-top: 1rem;
}

/* --------------------------------------------------------------------------
   闭合邀请区与页脚 (Forest-green ground with curved silhouette)
   -------------------------------------------------------------------------- */
.closing-and-footer {
  background-color: var(--dp-color-ink);
  color: var(--dp-color-ground);
  border-radius: 48px 48px 0 0;
  padding-top: 5rem;
  margin-top: 3rem;
  position: relative;
}

.closing-invitation {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 5rem auto;
  padding: 0 1.5rem;
}

.closing-invitation h2 {
  color: var(--dp-color-ground);
  font-size: clamp(2.1rem, 3.8vw, 3rem);
  margin-bottom: 1.25rem;
}

.closing-invitation p {
  color: var(--dp-color-panel);
  font-size: 1.0625rem;
  line-height: 1.65;
  opacity: 0.9;
  margin-bottom: 2rem;
}

.site-footer {
  border-top: var(--dp-border-hairline) solid var(--dp-color-field-line);
  padding: 2.5rem 0 3.5rem 0;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2rem;
  text-align: center;
}

/* 页脚只保留这四个标题链接 */
.footer-nav {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 2.5rem;
  list-style: none;
}

.footer-nav a {
  font-family: var(--dp-typography-display);
  font-size: 1.15rem;
  color: var(--dp-color-ground);
  opacity: 0.85;
  transition: opacity var(--dp-motion-interaction), color var(--dp-motion-interaction);
  padding: 0.25rem 0.5rem;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

.footer-nav a:hover {
  opacity: 1;
  color: var(--dp-color-warm-field);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.footer-copy {
  font-size: var(--dp-typography-metadata);
  color: var(--dp-color-panel);
  opacity: 0.7;
}

/* --------------------------------------------------------------------------
   知识科普文章专栏与独立文章页样式
   -------------------------------------------------------------------------- */
.knowledge-hero {
  text-align: center;
  padding: 3.5rem 0 2rem 0;
  max-width: 820px;
  margin: 0 auto;
}

.article-list-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
  margin: 2.5rem 0 4rem 0;
}

.article-summary-card {
  background-color: var(--dp-color-panel);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  border-radius: var(--dp-radius-panel-narrow);
  padding: 2rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 1.25rem;
  transition: transform var(--dp-motion-interaction) var(--dp-motion-easing), box-shadow var(--dp-motion-interaction) var(--dp-motion-easing);
}

.article-summary-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--dp-shadow-soft);
  border-color: var(--dp-color-accent);
}

.article-meta-row {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  font-size: var(--dp-typography-metadata);
  color: var(--dp-color-ink);
  opacity: 0.75;
  flex-wrap: wrap;
}

.article-content-container {
  max-width: 860px;
  margin: 0 auto;
  padding: 2.5rem 0 4rem 0;
}

.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: var(--dp-typography-metadata);
  color: var(--dp-color-ink);
  opacity: 0.8;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}

.breadcrumbs a:hover {
  color: var(--dp-color-accent);
  text-decoration: underline;
}

.article-hero-box {
  background-color: var(--dp-color-panel);
  border: var(--dp-border-hairline) solid var(--dp-color-ornament-line);
  border-radius: var(--dp-radius-panel);
  padding: 3rem 2.5rem;
  margin-bottom: 2.5rem;
}

.article-content {
  font-size: 1.0625rem;
  line-height: 1.85;
  color: var(--dp-color-ink);
}

.article-content h2 {
  font-size: 1.65rem;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  color: var(--dp-color-ink);
  border-bottom: var(--dp-border-hairline) solid var(--dp-color-rule);
  padding-bottom: 0.5rem;
}

.article-content h3 {
  font-size: 1.3rem;
  margin-top: 1.75rem;
  margin-bottom: 0.75rem;
}

.article-content p {
  margin-bottom: 1.35rem;
}

.article-content ul,
.article-content ol {
  margin-bottom: 1.5rem;
  padding-left: 1.75rem;
}

.article-content li {
  margin-bottom: 0.5rem;
}

.article-content a {
  color: var(--dp-color-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
  font-weight: 600;
}

.article-content a:hover {
  color: var(--dp-color-ink);
}

.article-cta-box {
  background-color: var(--dp-color-warm-field);
  border: var(--dp-border-hairline) solid var(--dp-color-accent);
  border-radius: 20px;
  padding: 2rem;
  margin: 2.5rem 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}

/* --------------------------------------------------------------------------
   响应式断点适配规范 (@media)
   -------------------------------------------------------------------------- */
@media (max-width: 1120px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }

  .hero-visual-wrap {
    order: 2;
  }

  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .reviews-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .article-list-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .section-wrapper {
    padding: 3.5rem 0;
  }

  .header-inner {
    flex-wrap: wrap;
  }

  .nav-menu {
    gap: 1rem;
    flex-wrap: wrap;
  }

  .hero-headline {
    font-size: 2.2rem;
  }

  .features-grid {
    grid-template-columns: 1fr;
  }

  .stream-ai-grid {
    grid-template-columns: 1fr;
  }

  .reviews-grid {
    grid-template-columns: 1fr;
  }

  .article-list-grid {
    grid-template-columns: 1fr;
  }

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

  .article-hero-box {
    padding: 2rem 1.5rem;
  }
}

@media (max-width: 480px) {
  .hero-arch-card {
    padding: 2rem 1.25rem;
    border-radius: 120px 120px var(--dp-radius-panel-narrow) var(--dp-radius-panel-narrow);
  }

  .hero-arch-inner {
    border-radius: 100px 100px calc(var(--dp-radius-panel-narrow) - 6px) calc(var(--dp-radius-panel-narrow) - 6px);
    padding: 1.5rem 1rem;
  }

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

  .hero-actions .btn {
    width: 100%;
  }

  .pricing-table-container {
    padding: 1rem;
  }
}

/* 减少动态效果偏好 */
@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;
  }
}