/* ==================================================
   青云梯机场 - 第2套视觉主题：踏板交替系统
   ================================================== */

:root {
  /* 配色系统 */
  --bg-main: #FAFAF7;
  --bg-white: #FFFFFF;
  --bg-secondary: #F1F2EE;
  
  --text-primary: #202729;
  --text-body: #5C6567;
  --text-muted: #899092;
  
  --cyan-gray: #45616B;
  --dark-cyan: #354E57;
  --pine-green: #557068;
  --dark-pine: #435A52;
  --warm-sand: #A57D59;
  --terracotta: #B16F51;
  
  --light-cyan-gray: #EDF1F1;
  --light-green: #EEF2EF;
  --light-warm: #F6EFE7;
  --border-color: #DEE1DB;
  
  /* 字体设置 */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  --line-height-body: 1.8;
  
  /* 容器与网格 */
  --site-max-width: 1140px;
  --article-max-width: 800px;
  --header-height: 70px;
}

/* 重置与基础设置 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-main);
  color: var(--text-body);
  overflow-x: hidden;
}

/* 键盘 Focus 样式 (A11y) */
:focus-visible {
  outline: 2px solid var(--cyan-gray);
  outline-offset: 3px;
}

a {
  color: var(--cyan-gray);
  text-decoration: none;
  transition: color 0.2s ease, border-color 0.2s ease;
}

a:hover {
  color: var(--dark-cyan);
}

p {
  margin-bottom: 1.25rem;
  font-size: 1.05rem;
  color: var(--text-body);
}

h1, h2, h3, h4, h5, h6 {
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.35;
  margin-bottom: 1rem;
}

h1 { font-size: 2.75rem; letter-spacing: -0.02em; }
h2 { font-size: 2.1rem; margin-top: 1rem; }
h3 { font-size: 1.45rem; }
h4 { font-size: 1.2rem; }

ul, ol {
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.4rem;
}

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

/* Header 导航 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--header-height);
  background-color: var(--bg-main);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
}

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

.brand-logo-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.site-logo-svg {
  width: 36px;
  height: 36px;
  display: block;
}

.brand-text {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.2;
}

.brand-subtext {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Nav Menu Desktop */
.nav-menu {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-link {
  font-size: 0.95rem;
  color: var(--text-body);
  padding: 0.4rem 0;
  position: relative;
  font-weight: 500;
}

.nav-link:hover, .nav-link.active {
  color: var(--cyan-gray);
}

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

/* Header CTA Button */
.btn-cta-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background-color: var(--cyan-gray);
  color: var(--bg-white) !important;
  padding: 0.55rem 1.25rem;
  border-radius: 4px;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid var(--dark-cyan);
  transition: background-color 0.2s ease, transform 0.2s ease;
}

.btn-cta-primary:hover {
  background-color: var(--dark-cyan);
  transform: translateX(2px);
}

.btn-cta-secondary {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background-color: transparent;
  color: var(--text-primary) !important;
  padding: 0.55rem 1.25rem;
  border-radius: 4px;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid var(--border-color);
  transition: background-color 0.2s ease;
}

.btn-cta-secondary:hover {
  background-color: var(--bg-secondary);
}

/* Mobile Toggle */
.mobile-nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 0.5rem;
  cursor: pointer;
  color: var(--text-primary);
}

.mobile-nav-toggle svg {
  width: 24px;
  height: 24px;
  display: block;
}

/* Mobile Menu Drawer */
.mobile-drawer {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--bg-main);
  z-index: 999;
  padding: 1.5rem;
  overflow-y: auto;
  border-top: 1px solid var(--border-color);
}

.mobile-drawer.open {
  display: block;
}

.mobile-nav-list {
  list-style: none;
  padding: 0;
  margin: 0 0 1.5rem 0;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.mobile-nav-list a {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  display: block;
  padding: 0.5rem 0;
  border-bottom: 1px border var(--border-color);
}

/* ==================================================
   踏板交替系统 (Plank Alternating System)
   ================================================== */

.section-padding {
  padding-top: 4.5rem;
  padding-bottom: 4.5rem;
  border-bottom: 1px solid var(--border-color);
}

.section-header {
  margin-bottom: 2.5rem;
}

.section-tag {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--warm-sand);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.section-title {
  font-size: 2.1rem;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.section-intro {
  font-size: 1.1rem;
  color: var(--text-body);
  max-width: 820px;
}

/* 踏板通用定义 */
.plank {
  position: relative;
  background-color: var(--bg-white);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  border-left: 3px solid transparent;
  padding: 1.5rem 1.75rem;
  margin-bottom: 1.5rem;
  border-radius: 2px;
  transition: border-color 0.2s ease, background-color 0.2s ease;
}

.plank:hover {
  background-color: #FEFEFC;
  border-top-color: var(--cyan-gray);
}

/* 踏板背景变体 */
.plank-bg-light-gray { background-color: var(--light-cyan-gray); }
.plank-bg-light-green { background-color: var(--light-green); }
.plank-bg-light-warm { background-color: var(--light-warm); }

/* 左右交替 Width & Alignment (Desktop) */
@media (min-width: 768px) {
  .plank-left {
    margin-right: auto;
    margin-left: 0;
  }
  
  .plank-right {
    margin-left: auto;
    margin-right: 0;
  }
  
  /* 踏板视觉比例 (长度不代表数据，只用于不对称排版) */
  .plank-w-72 { max-width: 72%; }
  .plank-w-64 { max-width: 64%; }
  .plank-w-79 { max-width: 79%; }
  .plank-w-58 { max-width: 58%; }
  .plank-w-68 { max-width: 68%; }
  .plank-w-74 { max-width: 74%; }
  .plank-w-82 { max-width: 82%; }
  .plank-w-70 { max-width: 70%; }
  .plank-w-88 { max-width: 88%; }
  .plank-w-100 { max-width: 100%; }
}

.plank-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.6rem;
  gap: 1rem;
}

.plank-num {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--cyan-gray);
  line-height: 1;
}

.plank-title {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0;
}

.plank-body {
  font-size: 1rem;
  color: var(--text-body);
  margin-bottom: 0.75rem;
}

.plank-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  font-size: 0.9rem;
}

.plank-link {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-weight: 600;
  color: var(--cyan-gray);
}

.plank-link:hover {
  color: var(--dark-cyan);
  text-decoration: underline;
}

/* ==================================================
   Hero 区域 (四块交替踏板)
   ================================================== */

.hero-section {
  padding-top: 3.5rem;
  padding-bottom: 4rem;
  background-color: var(--bg-main);
  border-bottom: 1px solid var(--border-color);
}

.hero-brand-block {
  margin-bottom: 2rem;
  max-width: 800px;
}

.hero-badge {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--pine-green);
  background-color: var(--light-green);
  padding: 0.25rem 0.75rem;
  border-radius: 2px;
  margin-bottom: 0.75rem;
  border: 1px solid #D5E2DB;
}

.hero-subhead {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
  line-height: 1.4;
}

.hero-title {
  font-size: 2.3rem;
  color: var(--text-primary);
  margin-bottom: 1rem;
  letter-spacing: -0.01em;
}

.hero-intro {
  font-size: 1.1rem;
  color: var(--text-body);
  margin-bottom: 1.75rem;
  line-height: 1.8;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
}

.hero-planks-wrapper {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

/* ==================================================
   五板价目 (07 / 完整价格)
   ================================================== */

.pricing-planks-wrapper {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 2rem;
}

.pricing-plank {
  padding: 1.75rem 2rem;
}

.pricing-plank-featured {
  background-color: var(--light-green);
  border-left: 4px solid var(--pine-green);
  border-top: 1px solid #CDE0D7;
  border-bottom: 1px solid #CDE0D7;
}

.pricing-plank-featured .plank-num {
  color: var(--pine-green);
}

.pricing-grid {
  display: grid;
  grid-template-columns: auto 1fr auto auto;
  align-items: center;
  gap: 1.5rem;
}

@media (max-width: 767px) {
  .pricing-grid {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }
}

.price-tag {
  font-size: 2.1rem;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1;
}

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

.plan-badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--bg-white);
  background-color: var(--terracotta);
  padding: 0.2rem 0.5rem;
  border-radius: 2px;
  margin-left: 0.5rem;
}

.pricing-disclaimer-note {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 1.5rem;
  padding: 0.75rem 1rem;
  background-color: var(--bg-secondary);
  border-left: 3px solid var(--warm-sand);
}

/* ==================================================
   表格样式 (03 / 线路知识 & 文章对比)
   ================================================== */

.table-wrapper {
  width: 100%;
  overflow-x: auto;
  margin-top: 1.5rem;
  margin-bottom: 2rem;
}

.custom-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
}

.custom-table th, .custom-table td {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
  font-size: 0.95rem;
}

.custom-table th {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  font-weight: 700;
  border-top: 1px solid var(--border-color);
}

.custom-table tr:nth-child(even) td {
  background-color: rgba(255, 255, 255, 0.5);
}

@media (max-width: 767px) {
  /* 移动端表格转成块状呈现 */
  .custom-table, .custom-table tbody, .custom-table tr, .custom-table td, .custom-table th {
    display: block;
    width: 100%;
  }
  
  .custom-table thead {
    display: none;
  }
  
  .custom-table tr {
    margin-bottom: 1.25rem;
    border: 1px solid var(--border-color);
    background-color: var(--bg-white);
    padding: 0.5rem;
  }
  
  .custom-table td {
    padding: 0.6rem 0.75rem;
    border-bottom: 1px dashed var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
  }
  
  .custom-table td:last-child {
    border-bottom: none;
  }
  
  .custom-table td::before {
    content: attr(data-label);
    font-weight: 700;
    color: var(--text-primary);
    margin-right: 1rem;
    min-width: 90px;
    flex-shrink: 0;
  }
}

/* ==================================================
   FAQ 问答踏板
   ================================================== */

.faq-planks-container {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-item {
  background-color: var(--bg-white);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  border-radius: 2px;
}

.faq-question-btn {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 1.25rem 1.5rem;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  gap: 1rem;
  font-family: inherit;
}

.faq-question-btn:hover {
  color: var(--cyan-gray);
}

.faq-icon {
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--text-muted);
  transition: transform 0.2s ease;
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
}

.faq-answer-content {
  display: none;
  padding: 0 1.5rem 1.25rem 1.5rem;
  color: var(--text-body);
  font-size: 1rem;
  line-height: 1.75;
  border-top: 1px dashed var(--border-color);
  margin-top: 0.25rem;
  padding-top: 1rem;
}

.faq-item.active .faq-answer-content {
  display: block;
}

/* Native details option fallback styling */
details.faq-item summary {
  padding: 1.25rem 1.5rem;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

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

details.faq-item[open] .faq-answer-content {
  display: block;
}

/* ==================================================
   文章与 GEO 内容结构
   ================================================== */

.article-layout {
  display: flex;
  gap: 2.5rem;
  margin-top: 2rem;
}

.article-main {
  flex: 1;
  max-width: var(--article-max-width);
}

.article-sidebar {
  width: 250px;
  flex-shrink: 0;
}

@media (max-width: 991px) {
  .article-layout {
    flex-direction: column;
  }
  .article-sidebar {
    width: 100%;
  }
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

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

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

.breadcrumb-separator {
  color: var(--border-color);
}

.article-header-meta {
  margin-bottom: 2rem;
}

.article-meta-bar {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  font-size: 0.88rem;
  color: var(--text-muted);
  padding: 0.75rem 1rem;
  background-color: var(--bg-secondary);
  border-left: 3px solid var(--cyan-gray);
  margin-top: 1rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.quick-conclusion-box {
  background-color: var(--light-cyan-gray);
  border-top: 1px solid var(--cyan-gray);
  border-bottom: 1px solid var(--cyan-gray);
  padding: 1.5rem 1.75rem;
  margin-bottom: 2.5rem;
  border-radius: 2px;
}

.quick-conclusion-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--dark-cyan);
  margin-bottom: 0.5rem;
}

/* 文章内部 H2 微错位 */
.article-content h2 {
  font-size: 1.75rem;
  margin-top: 2.5rem;
  margin-bottom: 1.25rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-color);
}

.article-content h2.offset-right {
  margin-left: 1rem;
}

.article-content h3 {
  font-size: 1.3rem;
  margin-top: 1.75rem;
  margin-bottom: 0.85rem;
}

.toc-box {
  position: sticky;
  top: calc(var(--header-height) + 1.5rem);
  background-color: var(--bg-white);
  border: 1px solid var(--border-color);
  padding: 1.25rem;
  border-radius: 2px;
}

.toc-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.toc-list {
  list-style: none;
  padding: 0;
  margin: 0;
  font-size: 0.88rem;
}

.toc-list li {
  margin-bottom: 0.5rem;
}

.toc-list a {
  color: var(--text-body);
}

.toc-list a:hover {
  color: var(--cyan-gray);
}

.related-articles-section {
  margin-top: 3.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

/* ==================================================
   Footer (浅灰绿、紧凑排版)
   ================================================== */

.site-footer {
  background-color: var(--bg-secondary);
  color: #4C5658;
  border-top: 1px solid var(--border-color);
  padding-top: 3rem;
  padding-bottom: 2rem;
  margin-top: auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2.5rem;
}

@media (max-width: 991px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 575px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-col-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.footer-col-offset {
  margin-top: 0.5rem; /* 保持非常微弱的交替关系 */
}

.footer-links-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-links-list li {
  margin-bottom: 0.6rem;
}

.footer-links-list a {
  color: #4C5658;
  font-size: 0.9rem;
}

.footer-links-list a:hover {
  color: var(--dark-cyan);
}

.footer-bottom {
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.88rem;
}

.friend-links-group {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.friend-links-group a {
  color: #4C5658;
  font-weight: 500;
}

.friend-links-group a:hover {
  color: var(--cyan-gray);
}

/* ==================================================
   Mobile Responsive Adjustments
   ================================================== */

@media (max-width: 767px) {
  .nav-menu { display: none; }
  .mobile-nav-toggle { display: block; }
  
  h1 { font-size: 2rem; }
  h2 { font-size: 1.6rem; }
  .section-title { font-size: 1.6rem; }
  
  /* 手机端取消明显左右位移，归零单列，保留轻微 4px-12px 缩进 */
  .plank-left, .plank-right {
    margin-left: 0 !important;
    margin-right: 0 !important;
    max-width: 100% !important;
    padding-left: 1.25rem;
    padding-right: 1.25rem;
  }
  
  .plank-right {
    padding-left: 1.5rem; /* 轻微 4px-12px 交替缩进 */
  }
  
  .hero-section {
    padding-top: 2rem;
    padding-bottom: 2.5rem;
  }
  
  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* ==================================================
   Accessibility: Prefers-Reduced-Motion
   ================================================== */

@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;
  }
}