/* ==========================================================================
   大哥云机场 (dageyun-jichang.wiki) - 核心样式表
   世界观：天文台 (Observatory)
   画风：低多边形 (Low Poly / Geodesic Facets)
   版式原型：横向卷轴 (Horizontal Scroll / Panoramic Atlas)
   配色方案：主色相 86° (黄绿/苔藓橄榄)，双色印刷 (Duotone)
   架构规范：纯原生 CSS3，BEM 命名规范，零外部 CDN，完全无障碍
   ========================================================================== */

:root {
  --nn-font-system: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  
  /* 86° 主色系 (双色印刷主色：黄绿苔藓橄榄) */
  --nn-primary: #5c8f12;
  --nn-primary-hover: #4b770e;
  --nn-primary-light: #f3f8ec;
  --nn-primary-border: #d4e5be;
  --nn-primary-dark: #37570b;

  /* 双色印刷底墨 (深橄榄岩黑) */
  --nn-ink: #131b0e;
  --nn-ink-soft: #202c17;
  --nn-ink-muted: #4e5e40;
  --nn-ink-light: #7b8e6c;

  /* 纸张与表面底色 */
  --nn-bg: #f8faf4;
  --nn-surface: #ffffff;
  --nn-surface-alt: #f0f5e8;
  --nn-surface-facets: #e7eedc;

  /* 边框与刻度线 */
  --nn-border: #d8e4c7;
  --nn-border-dark: #1e2a14;
  --nn-border-light: #eaf1df;

  /* 状态与度量 */
  --nn-active-indicator: #5c8f12;
  --nn-max-width: 1180px;

  /* 圆角与阴影 */
  --nn-radius-sm: 4px;
  --nn-radius-md: 8px;
  --nn-radius-lg: 14px;
  --nn-radius-full: 9999px;

  --nn-shadow-sm: 0 1px 3px rgba(19, 27, 14, 0.06);
  --nn-shadow-md: 0 4px 8px -1px rgba(19, 27, 14, 0.08), 0 2px 4px -2px rgba(19, 27, 14, 0.04);
  --nn-shadow-lg: 0 12px 24px -4px rgba(19, 27, 14, 0.1), 0 4px 8px -2px rgba(19, 27, 14, 0.05);
  --nn-shadow-poly: 0 8px 0px rgba(19, 27, 14, 0.9);

  --nn-transition: 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

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

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

body {
  font-family: var(--nn-font-system);
  background-color: var(--nn-bg);
  color: var(--nn-ink);
  line-height: 1.68;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

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

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

ul, ol {
  list-style: none;
}

/* 容器与网格 */
.nn-container {
  width: 100%;
  max-width: var(--nn-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

/* 按钮规范 */
.nn-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.95rem;
  line-height: 1;
  padding: 13px 26px;
  border-radius: var(--nn-radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: all var(--nn-transition);
  white-space: nowrap;
}

.nn-btn:focus-visible {
  outline: 2px solid var(--nn-primary);
  outline-offset: 2px;
}

.nn-btn--primary {
  background-color: var(--nn-primary);
  color: #ffffff;
  border-color: var(--nn-primary-dark);
  box-shadow: 0 2px 0 var(--nn-primary-dark);
}

.nn-btn--primary:hover {
  background-color: var(--nn-primary-hover);
  color: #ffffff;
  transform: translateY(-1px);
  box-shadow: 0 3px 0 var(--nn-primary-dark);
}

.nn-btn--outline {
  background-color: var(--nn-surface);
  color: var(--nn-ink);
  border-color: var(--nn-border);
}

.nn-btn--outline:hover {
  background-color: var(--nn-surface-alt);
  border-color: var(--nn-ink-muted);
  color: var(--nn-ink);
}

.nn-btn--sm {
  padding: 8px 18px;
  font-size: 0.85rem;
  border-radius: var(--nn-radius-sm);
}

.nn-btn--block {
  display: flex;
  width: 100%;
}

/* 天文台双色徽章 */
.nn-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border-radius: var(--nn-radius-full);
  font-size: 0.8rem;
  font-weight: 700;
  background-color: var(--nn-primary-light);
  color: var(--nn-primary-dark);
  border: 1px solid var(--nn-primary-border);
  letter-spacing: 0.02em;
}

/* ==========================================================================
   Header 导航栏
   ========================================================================== */
.nn-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(248, 250, 244, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--nn-border);
}

.nn-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.nn-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  font-weight: 800;
  font-size: 1.2rem;
  color: var(--nn-ink);
}

.nn-logo svg {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
}

.nn-logo__badge {
  font-size: 0.72rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: var(--nn-radius-full);
  background: var(--nn-surface-alt);
  color: var(--nn-primary-dark);
  border: 1px solid var(--nn-primary-border);
}

.nn-nav {
  display: flex;
  align-items: center;
  gap: 30px;
}

.nn-nav__link {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--nn-ink-muted);
  transition: color var(--nn-transition);
}

.nn-nav__link:hover,
.nn-nav__link.is-active {
  color: var(--nn-primary-dark);
}

.nn-header__actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

.nn-menu-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-sm);
  padding: 6px;
  cursor: pointer;
  color: var(--nn-ink);
}

/* ==========================================================================
   Hero 主视觉 (天文台 / 低多边形望远镜交互)
   ========================================================================== */
.nn-hero {
  padding: 72px 0 60px;
  background: radial-gradient(circle at 50% 0%, #edf5e3 0%, #f8faf4 75%);
  border-bottom: 1px solid var(--nn-border);
  position: relative;
  overflow: hidden;
}

.nn-hero__grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 48px;
  align-items: center;
}

.nn-hero__content {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.nn-hero__headline {
  font-size: 2.45rem;
  font-weight: 800;
  line-height: 1.28;
  color: var(--nn-ink);
  letter-spacing: -0.02em;
}

.nn-hero__subheadline {
  font-size: 1.1rem;
  line-height: 1.72;
  color: var(--nn-ink-muted);
}

.nn-hero__actions {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 8px;
  flex-wrap: wrap;
}

.nn-hero__trust {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-top: 12px;
  font-size: 0.85rem;
  color: var(--nn-ink-muted);
  flex-wrap: wrap;
}

.nn-hero__trust-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.nn-hero__trust-item svg {
  width: 16px;
  height: 16px;
  color: var(--nn-primary);
}

/* 招牌动效：天文台望远镜视角盘 (Observatory Reticle Tracker) */
.nn-hero__observatory-box {
  background-color: var(--nn-surface);
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-lg);
  padding: 24px;
  box-shadow: var(--nn-shadow-md);
  position: relative;
}

.nn-observatory-reticle {
  width: 100%;
  aspect-ratio: 16 / 10;
  background: linear-gradient(135deg, #131b0e 0%, #1f2b16 100%);
  border-radius: var(--nn-radius-md);
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--nn-primary-border);
}

/* 低多边形星轨与光标十字准星 */
.nn-reticle-tracker {
  position: absolute;
  width: 140px;
  height: 140px;
  border: 1px dashed rgba(180, 220, 140, 0.4);
  border-radius: 50%;
  pointer-events: none;
  transform: translate(0px, 0px);
  transition: transform 0.1s ease-out;
  display: flex;
  align-items: center;
  justify-content: center;
}

.nn-reticle-tracker::before,
.nn-reticle-tracker::after {
  content: "";
  position: absolute;
  background-color: rgba(180, 220, 140, 0.6);
}

.nn-reticle-tracker::before {
  width: 100%;
  height: 1px;
}

.nn-reticle-tracker::after {
  height: 100%;
  width: 1px;
}

.nn-reticle-center-dot {
  width: 8px;
  height: 8px;
  background-color: var(--nn-primary);
  border-radius: 50%;
  box-shadow: 0 0 8px rgba(110, 168, 24, 0.8);
}

.nn-observatory-legend {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 14px;
  font-size: 0.8rem;
  color: var(--nn-ink-muted);
}

.nn-observatory-legend span {
  display: flex;
  align-items: center;
  gap: 6px;
}

.nn-observatory-legend-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--nn-primary);
}

/* ==========================================================================
   通栏通用章节结构
   ========================================================================== */
.nn-section {
  padding: 80px 0;
}

.nn-section--alt {
  background-color: #ffffff;
  border-top: 1px solid var(--nn-border);
  border-bottom: 1px solid var(--nn-border);
}

.nn-section__header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 52px;
}

.nn-section__title {
  font-size: 2rem;
  font-weight: 800;
  color: var(--nn-ink);
  margin-top: 10px;
  margin-bottom: 12px;
  letter-spacing: -0.01em;
}

.nn-section__desc {
  font-size: 1.05rem;
  color: var(--nn-ink-muted);
  line-height: 1.65;
}

/* ==========================================================================
   模块 1: 人群对照 (三列对照)
   ========================================================================== */
.nn-audience-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.nn-audience-card {
  background-color: var(--nn-surface);
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-lg);
  padding: 32px 26px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: transform var(--nn-transition), border-color var(--nn-transition);
}

.nn-audience-card:hover {
  transform: translateY(-2px);
  border-color: var(--nn-primary);
}

.nn-audience-card__header {
  margin-bottom: 20px;
}

.nn-audience-card__tag {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--nn-primary-dark);
  background-color: var(--nn-primary-light);
  border: 1px solid var(--nn-primary-border);
  padding: 3px 10px;
  border-radius: var(--nn-radius-full);
  display: inline-block;
  margin-bottom: 12px;
}

.nn-audience-card__title {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--nn-ink);
  margin-bottom: 6px;
}

.nn-audience-card__core-care {
  background-color: var(--nn-surface-alt);
  border-radius: var(--nn-radius-md);
  padding: 16px;
  margin-bottom: 18px;
  font-size: 0.88rem;
  color: var(--nn-ink-soft);
  line-height: 1.6;
}

.nn-audience-card__care-title {
  font-weight: 700;
  color: var(--nn-primary-dark);
  margin-bottom: 4px;
  font-size: 0.82rem;
}

.nn-audience-card__rec {
  border-top: 1px dashed var(--nn-border);
  padding-top: 14px;
  font-size: 0.85rem;
  color: var(--nn-ink-muted);
}

.nn-audience-card__rec-plan {
  font-weight: 700;
  color: var(--nn-ink);
}

/* ==========================================================================
   模块 2: 使用场景 (4张，形态「横向滑动条」)
   ========================================================================== */
.nn-scenarios-scroll-wrapper {
  overflow-x: auto;
  padding-bottom: 24px;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  margin-left: -20px;
  margin-right: -20px;
  padding-left: 20px;
  padding-right: 20px;
}

.nn-scenarios-track {
  display: flex;
  gap: 24px;
  width: max-content;
}

.nn-scenario-card {
  width: 320px;
  background-color: var(--nn-surface);
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-lg);
  padding: 26px;
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  flex-shrink: 0;
}

.nn-scenario-card__header {
  margin-bottom: 14px;
}

.nn-scenario-card__time {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--nn-primary-dark);
  background: var(--nn-primary-light);
  padding: 2px 8px;
  border-radius: var(--nn-radius-sm);
  display: inline-block;
  margin-bottom: 10px;
}

.nn-scenario-card__title {
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--nn-ink);
  margin-bottom: 6px;
}

.nn-scenario-card__device {
  font-size: 0.82rem;
  color: var(--nn-ink-light);
  display: flex;
  align-items: center;
  gap: 6px;
}

.nn-scenario-card__desc {
  font-size: 0.9rem;
  color: var(--nn-ink-muted);
  line-height: 1.65;
  background-color: var(--nn-surface-alt);
  padding: 14px;
  border-radius: var(--nn-radius-md);
}

/* ==========================================================================
   模块 3: AI 支持 (纯文字与统一线性 SVG 说明)
   ========================================================================== */
.nn-ai-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.nn-ai-item {
  background-color: var(--nn-surface);
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-md);
  padding: 20px;
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.nn-ai-item__icon {
  width: 40px;
  height: 40px;
  border-radius: var(--nn-radius-sm);
  background-color: var(--nn-surface-alt);
  color: var(--nn-primary-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.nn-ai-item__icon svg {
  width: 20px;
  height: 20px;
}

.nn-ai-item__text h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--nn-ink);
  margin-bottom: 4px;
}

.nn-ai-item__text p {
  font-size: 0.85rem;
  color: var(--nn-ink-muted);
  line-height: 1.5;
}

/* ==========================================================================
   模块 4: 定价 (3档，形态「月付年付切换标签」，推荐中档)
   ========================================================================== */
.nn-pricing-toggle-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-bottom: 40px;
}

.nn-pricing-toggle {
  display: inline-flex;
  background-color: var(--nn-surface-alt);
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-full);
  padding: 4px;
}

.nn-pricing-toggle__btn {
  padding: 8px 22px;
  border-radius: var(--nn-radius-full);
  border: none;
  background: transparent;
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--nn-ink-muted);
  cursor: pointer;
  transition: all var(--nn-transition);
  font-family: inherit;
}

.nn-pricing-toggle__btn.is-active {
  background-color: var(--nn-surface);
  color: var(--nn-ink);
  box-shadow: var(--nn-shadow-sm);
}

.nn-pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  align-items: stretch;
}

.nn-pricing-card {
  background-color: var(--nn-surface);
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-lg);
  padding: 36px 30px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  transition: border-color var(--nn-transition);
}

.nn-pricing-card--popular {
  border-color: var(--nn-primary);
  border-width: 2px;
  box-shadow: 0 8px 20px -2px rgba(92, 143, 18, 0.15);
}

.nn-pricing-card__badge {
  position: absolute;
  top: -13px;
  left: 50%;
  transform: translateX(-50%);
  background-color: var(--nn-primary);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 14px;
  border-radius: var(--nn-radius-full);
  letter-spacing: 0.04em;
}

.nn-pricing-card__title {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--nn-ink);
  margin-bottom: 6px;
}

.nn-pricing-card__positioning {
  font-size: 0.88rem;
  color: var(--nn-ink-muted);
  margin-bottom: 18px;
}

.nn-pricing-card__rate-box {
  background-color: var(--nn-surface-alt);
  border: 1px dashed var(--nn-border);
  border-radius: var(--nn-radius-md);
  padding: 16px;
  text-align: center;
  margin-bottom: 22px;
}

.nn-pricing-card__rate-period {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--nn-primary-dark);
  margin-bottom: 2px;
}

.nn-pricing-card__rate-note {
  font-size: 0.78rem;
  color: var(--nn-ink-muted);
}

.nn-pricing-card__audience {
  margin-bottom: 20px;
}

.nn-pricing-card__audience-title {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--nn-ink);
  margin-bottom: 6px;
}

.nn-pricing-card__audience-desc {
  font-size: 0.86rem;
  color: var(--nn-ink-muted);
  line-height: 1.55;
}

.nn-pricing-card__features {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 28px;
  border-top: 1px solid var(--nn-border-light);
  padding-top: 18px;
}

.nn-pricing-card__feature-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--nn-ink-muted);
}

.nn-pricing-card__feature-item svg {
  width: 16px;
  height: 16px;
  color: var(--nn-primary);
  flex-shrink: 0;
}

/* ==========================================================================
   模块 5: 特性 (4项，形态「卡片网格」)
   ========================================================================== */
.nn-features-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}

.nn-feature-card {
  background-color: var(--nn-surface);
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-lg);
  padding: 32px 28px;
  display: flex;
  gap: 20px;
  align-items: flex-start;
  transition: border-color var(--nn-transition);
}

.nn-feature-card:hover {
  border-color: var(--nn-primary);
}

.nn-feature-card__icon {
  width: 48px;
  height: 48px;
  border-radius: var(--nn-radius-md);
  background-color: var(--nn-primary-light);
  color: var(--nn-primary-dark);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.nn-feature-card__icon svg {
  width: 24px;
  height: 24px;
}

.nn-feature-card__content h3 {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--nn-ink);
  margin-bottom: 8px;
}

.nn-feature-card__content p {
  font-size: 0.9rem;
  color: var(--nn-ink-muted);
  line-height: 1.65;
}

/* ==========================================================================
   模块 6: FAQ (5条，形态「单列手风琴」)
   ========================================================================== */
.nn-faq-list {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

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

.nn-faq-item.is-open {
  border-color: var(--nn-primary);
  box-shadow: var(--nn-shadow-sm);
}

.nn-faq-btn {
  width: 100%;
  text-align: left;
  padding: 20px 24px;
  background: transparent;
  border: none;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--nn-ink);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  font-family: inherit;
}

.nn-faq-btn:focus-visible {
  outline: 2px solid var(--nn-primary);
}

.nn-faq-icon {
  width: 20px;
  height: 20px;
  color: var(--nn-ink-light);
  transition: transform var(--nn-transition);
  flex-shrink: 0;
}

.nn-faq-item.is-open .nn-faq-icon {
  transform: rotate(180deg);
  color: var(--nn-primary);
}

.nn-faq-answer {
  display: none;
  padding: 0 24px 22px;
  font-size: 0.95rem;
  color: var(--nn-ink-muted);
  line-height: 1.7;
}

.nn-faq-item.is-open .nn-faq-answer {
  display: block;
}

/* ==========================================================================
   Final CTA
   ========================================================================== */
.nn-final-cta {
  background: linear-gradient(180deg, #f8faf4 0%, #e8f0dc 100%);
  padding: 88px 0;
  text-align: center;
  border-top: 1px solid var(--nn-border);
}

.nn-final-cta__box {
  max-width: 680px;
  margin: 0 auto;
}

.nn-final-cta__title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--nn-ink);
  margin-bottom: 16px;
  letter-spacing: -0.01em;
}

.nn-final-cta__desc {
  font-size: 1.1rem;
  color: var(--nn-ink-muted);
  margin-bottom: 32px;
  line-height: 1.65;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.nn-footer {
  background-color: #ffffff;
  border-top: 1px solid var(--nn-border);
  padding: 64px 0 32px;
  margin-top: auto;
}

.nn-footer__grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.nn-footer__brand p {
  font-size: 0.88rem;
  color: var(--nn-ink-muted);
  margin-top: 14px;
  line-height: 1.6;
  max-width: 360px;
}

.nn-footer__col-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--nn-ink);
  margin-bottom: 18px;
}

.nn-footer__links {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.nn-footer__links a {
  font-size: 0.88rem;
  color: var(--nn-ink-muted);
}

.nn-footer__links a:hover {
  color: var(--nn-primary-dark);
}

.nn-footer__bottom {
  border-top: 1px solid var(--nn-border-light);
  padding-top: 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.825rem;
  color: var(--nn-ink-light);
  flex-wrap: wrap;
  gap: 16px;
}

/* ==========================================================================
   移动端吸底 CTA
   ========================================================================== */
.nn-mobile-bottom-bar {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 99;
  background-color: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-top: 1px solid var(--nn-border);
  padding: 12px 20px;
  box-shadow: 0 -4px 12px rgba(19, 27, 14, 0.08);
  transform: translateY(100%);
  transition: transform 0.25s ease-in-out;
}

.nn-mobile-bottom-bar.is-visible {
  transform: translateY(0);
}

.nn-mobile-bottom-bar__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}

.nn-mobile-bottom-bar__info {
  display: flex;
  flex-direction: column;
}

.nn-mobile-bottom-bar__text {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--nn-ink);
}

.nn-mobile-bottom-bar__sub {
  font-size: 0.72rem;
  color: var(--nn-ink-muted);
}

/* ==========================================================================
   文章与合规页通用排版
   ========================================================================== */
.nn-article-page {
  padding: 40px 0 80px;
}

.nn-breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--nn-ink-light);
  margin-bottom: 24px;
  flex-wrap: wrap;
}

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

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

.nn-article-header {
  max-width: 860px;
  margin-bottom: 36px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--nn-border);
}

.nn-article-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--nn-ink);
  line-height: 1.3;
  margin-top: 12px;
  margin-bottom: 16px;
  letter-spacing: -0.01em;
}

.nn-article-meta {
  display: flex;
  align-items: center;
  gap: 20px;
  font-size: 0.85rem;
  color: var(--nn-ink-light);
  flex-wrap: wrap;
}

.nn-article-lead {
  font-size: 1.1rem;
  line-height: 1.75;
  color: var(--nn-ink-soft);
  background-color: var(--nn-surface);
  border-left: 4px solid var(--nn-primary);
  padding: 18px 24px;
  border-radius: 0 var(--nn-radius-md) var(--nn-radius-md) 0;
  margin-bottom: 36px;
  box-shadow: var(--nn-shadow-sm);
}

.nn-article-body {
  max-width: 860px;
  font-size: 1.025rem;
  line-height: 1.8;
  color: var(--nn-ink);
}

.nn-article-body h2 {
  font-size: 1.55rem;
  font-weight: 800;
  color: var(--nn-ink);
  margin-top: 48px;
  margin-bottom: 18px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--nn-border-light);
}

.nn-article-body h3 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--nn-ink);
  margin-top: 28px;
  margin-bottom: 12px;
}

.nn-article-body p {
  margin-bottom: 20px;
  color: #2b3921;
}

.nn-article-body ul, 
.nn-article-body ol {
  margin-bottom: 24px;
  padding-left: 24px;
}

.nn-article-body ul {
  list-style-type: disc;
}

.nn-article-body ol {
  list-style-type: decimal;
}

.nn-article-body li {
  margin-bottom: 10px;
  color: #2b3921;
}

.nn-step-box {
  background-color: var(--nn-surface);
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-md);
  padding: 20px;
  margin-bottom: 20px;
}

.nn-step-box__title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--nn-primary-dark);
  margin-bottom: 8px;
}

.nn-callout {
  padding: 18px 22px;
  border-radius: var(--nn-radius-md);
  margin: 28px 0;
  border: 1px solid var(--nn-border);
  background-color: var(--nn-surface);
}

.nn-callout--tip {
  border-left: 4px solid var(--nn-primary);
  background-color: var(--nn-primary-light);
}

.nn-callout--warn {
  border-left: 4px solid #b45309;
  background-color: #fffbeb;
}

.nn-callout__title {
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 6px;
  color: var(--nn-ink);
}

.nn-table-wrapper {
  overflow-x: auto;
  margin: 28px 0;
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-md);
}

.nn-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.925rem;
  background-color: var(--nn-surface);
}

.nn-table th, 
.nn-table td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--nn-border-light);
}

.nn-table th {
  background-color: var(--nn-surface-alt);
  font-weight: 700;
  color: var(--nn-ink);
}

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

.nn-article-cta {
  background: linear-gradient(135deg, #131b0e 0%, #202c17 100%);
  color: #ffffff;
  padding: 36px 32px;
  border-radius: var(--nn-radius-lg);
  margin: 48px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.nn-article-cta__text h3 {
  font-size: 1.35rem;
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 8px;
}

.nn-article-cta__text p {
  font-size: 0.925rem;
  color: #d1e0bd;
  margin-bottom: 0;
}

.nn-related-articles {
  margin-top: 48px;
  padding-top: 36px;
  border-top: 1px solid var(--nn-border);
}

.nn-related-articles__title {
  font-size: 1.3rem;
  font-weight: 800;
  margin-bottom: 20px;
}

.nn-related-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.nn-related-item {
  background-color: var(--nn-surface);
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-md);
  padding: 18px 20px;
  transition: all var(--nn-transition);
}

.nn-related-item:hover {
  border-color: var(--nn-primary);
  transform: translateY(-2px);
  box-shadow: var(--nn-shadow-sm);
}

.nn-related-item h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--nn-ink);
  margin-bottom: 6px;
}

.nn-related-item p {
  font-size: 0.825rem;
  color: var(--nn-ink-muted);
  margin-bottom: 0;
}

/* 指南页卡片 */
.nn-tutorials-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.nn-tutorial-card {
  background-color: var(--nn-surface);
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-lg);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all var(--nn-transition);
}

.nn-tutorial-card:hover {
  transform: translateY(-3px);
  border-color: var(--nn-primary);
  box-shadow: var(--nn-shadow-md);
}

.nn-tutorial-card__meta {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
  font-size: 0.78rem;
  color: var(--nn-ink-light);
}

.nn-tutorial-card__category {
  font-weight: 600;
  color: var(--nn-primary-dark);
  background-color: var(--nn-primary-light);
  padding: 2px 8px;
  border-radius: var(--nn-radius-sm);
}

.nn-tutorial-card__title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--nn-ink);
  margin-bottom: 10px;
  line-height: 1.4;
}

.nn-tutorial-card__desc {
  font-size: 0.9rem;
  color: var(--nn-ink-muted);
  line-height: 1.6;
  margin-bottom: 20px;
}

.nn-tutorial-card__link {
  font-weight: 700;
  font-size: 0.88rem;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

/* 合规页容器 */
.nn-legal-box {
  background-color: var(--nn-surface);
  border: 1px solid var(--nn-border);
  border-radius: var(--nn-radius-lg);
  padding: 48px;
  margin: 40px auto 80px;
  max-width: 900px;
  box-shadow: var(--nn-shadow-sm);
}

.nn-legal-box h1 {
  font-size: 2.1rem;
  font-weight: 800;
  color: var(--nn-ink);
  margin-bottom: 12px;
}

.nn-legal-box__date {
  font-size: 0.85rem;
  color: var(--nn-ink-light);
  padding-bottom: 24px;
  border-bottom: 1px solid var(--nn-border-light);
  margin-bottom: 32px;
}

.nn-legal-box h2 {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--nn-ink);
  margin-top: 36px;
  margin-bottom: 14px;
}

.nn-legal-box p {
  font-size: 0.95rem;
  color: #2b3921;
  line-height: 1.8;
  margin-bottom: 16px;
}

.nn-legal-box ul {
  list-style-type: disc;
  padding-left: 24px;
  margin-bottom: 20px;
}

.nn-legal-box li {
  font-size: 0.95rem;
  color: #2b3921;
  margin-bottom: 8px;
}

/* ==========================================================================
   响应式断点
   ========================================================================== */
@media (max-width: 992px) {
  .nn-hero__grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .nn-audience-grid,
  .nn-pricing-grid,
  .nn-tutorials-grid,
  .nn-ai-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .nn-footer__grid {
    grid-template-columns: 1fr 1fr;
    gap: 36px;
  }
}

@media (max-width: 768px) {
  .nn-nav {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background-color: #ffffff;
    border-bottom: 1px solid var(--nn-border);
    flex-direction: column;
    padding: 24px 20px;
    gap: 18px;
    box-shadow: var(--nn-shadow-md);
  }

  .nn-nav.is-open {
    display: flex;
  }

  .nn-menu-toggle {
    display: block;
  }

  .nn-hero {
    padding: 48px 0 40px;
  }

  .nn-hero__headline {
    font-size: 1.95rem;
  }

  .nn-section {
    padding: 56px 0;
  }

  .nn-section__title {
    font-size: 1.65rem;
  }

  .nn-audience-grid,
  .nn-features-grid,
  .nn-pricing-grid,
  .nn-tutorials-grid,
  .nn-ai-grid,
  .nn-related-grid {
    grid-template-columns: 1fr;
  }

  .nn-article-cta {
    flex-direction: column;
    text-align: center;
  }

  .nn-footer__grid {
    grid-template-columns: 1fr;
  }

  .nn-footer__bottom {
    flex-direction: column;
    align-items: flex-start;
  }

  .nn-legal-box {
    padding: 24px;
    margin: 20px auto 60px;
  }

  .nn-mobile-bottom-bar {
    display: block;
  }

  body {
    padding-bottom: 64px;
  }
}

@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;
  }
}