/* ==========================================================================
   一云梯机场 (Yiyunti Airport) - Unified Design System & Styling
   Theme: Pure White Minimalist (纯白色 简约风) with Embedded Cards (卡片嵌入式)
   ========================================================================== */

:root {
  --bg-main: #ffffff;
  --bg-subtle: #f8fafc;
  --bg-card: #ffffff;
  --bg-card-hover: #f1f5f9;
  
  --primary-blue: #2563eb;
  --primary-blue-hover: #1d4ed8;
  --primary-blue-light: #eff6ff;
  --primary-blue-border: #bfdbfe;
  
  --text-main: #0f172a;
  --text-muted: #475569;
  --text-light: #64748b;
  
  --border-color: #e2e8f0;
  --border-highlight: #3b82f6;
  
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 24px;
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.03);
  --shadow-card: 0 10px 30px rgba(15, 23, 42, 0.05);
  --shadow-hover: 0 18px 40px rgba(37, 99, 235, 0.12);
  
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --max-width: 1200px;
}

/* Reset & Base Setup */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  background-color: var(--bg-main);
  color: var(--text-main);
}

body {
  font-family: var(--font-family);
  line-height: 1.6;
  background-color: var(--bg-main);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

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

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 700;
  line-height: 1.3;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.35rem; }

p { color: var(--text-muted); }

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* Button Styles */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  font-size: 1rem;
  font-weight: 600;
  border-radius: 50px;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  cursor: pointer;
  border: 1px solid transparent;
  gap: 8px;
  text-align: center;
}

.btn-primary {
  background-color: var(--primary-blue);
  color: #ffffff !important;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.35);
}

.btn-primary:hover {
  background-color: var(--primary-blue-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.45);
}

.btn-outline {
  background-color: #ffffff;
  color: var(--primary-blue) !important;
  border-color: var(--primary-blue);
}

.btn-outline:hover {
  background-color: var(--primary-blue-light);
  transform: translateY(-2px);
}

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

.btn-secondary:hover {
  background-color: #e2e8f0;
  transform: translateY(-2px);
}

.btn-block {
  width: 100%;
  padding: 14px 20px;
}

/* Header & Navigation */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  padding: 16px 0;
}

.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--primary-blue);
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, #2563eb, #60a5fa);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  font-size: 1.2rem;
}

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

.nav-link {
  font-size: 0.98rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.2s ease;
}

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

.mobile-toggle {
  display: none;
  font-size: 1.5rem;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-main);
}

/* Embedded Card Section Wrapper */
.section {
  padding: 80px 0;
}

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

.section-title-wrap {
  text-align: center;
  max-width: 760px;
  margin: 0 auto 50px auto;
}

.badge {
  display: inline-block;
  padding: 6px 16px;
  background-color: var(--primary-blue-light);
  color: var(--primary-blue);
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: 30px;
  margin-bottom: 12px;
  letter-spacing: 0.5px;
}

.section-title {
  font-size: 2.2rem;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 1.1rem;
  color: var(--text-muted);
}

/* HERO SECTION (Left: Cloud Image, Right: Text) */
.hero {
  padding: 60px 0 90px 0;
  background: radial-gradient(circle at 10% 20%, rgba(239, 246, 255, 0.7) 0%, rgba(255, 255, 255, 1) 90%);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 50px;
  align-items: center;
}

.hero-left {
  position: relative;
}

.hero-image-card {
  background: #ffffff;
  border-radius: var(--radius-xl);
  padding: 16px;
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border-color);
  overflow: hidden;
  transition: transform 0.3s ease;
}

.hero-image-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.hero-image-card img {
  border-radius: var(--radius-lg);
  width: 100%;
  object-fit: cover;
}

.hero-right {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.hero-title {
  font-size: 2.8rem;
  line-height: 1.2;
  margin-bottom: 20px;
  color: var(--text-main);
}

.hero-title span {
  color: var(--primary-blue);
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin-bottom: 30px;
  line-height: 1.7;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 32px;
}

.hero-tag {
  background: #ffffff;
  border: 1px solid var(--border-color);
  padding: 6px 14px;
  border-radius: 8px;
  font-size: 0.88rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
}

.hero-tag svg {
  fill: var(--primary-blue);
}

.hero-cta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

/* Feature Grid (Cards Embedded) */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 30px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-card);
  transition: all 0.3s ease;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-hover);
  border-color: var(--primary-blue-border);
}

.feature-icon {
  width: 54px;
  height: 54px;
  border-radius: 14px;
  background-color: var(--primary-blue-light);
  color: var(--primary-blue);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 20px;
}

.feature-title {
  font-size: 1.25rem;
  margin-bottom: 12px;
}

.feature-desc {
  font-size: 0.95rem;
  line-height: 1.6;
}

/* PRICING SECTION (Matching Reference Screenshot) */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 30px;
  align-items: stretch;
}

.pricing-card {
  background: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 36px 30px;
  display: flex;
  flex-direction: column;
  position: relative;
  box-shadow: var(--shadow-card);
  transition: all 0.3s ease;
}

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

.pricing-card.featured {
  border: 2px solid var(--primary-blue);
  box-shadow: 0 12px 36px rgba(37, 99, 235, 0.15);
}

.pricing-card-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary-blue);
  color: #ffffff;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 4px 16px;
  border-radius: 20px;
  letter-spacing: 0.5px;
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.3);
}

.pricing-tag-subtle {
  display: inline-block;
  align-self: flex-start;
  padding: 4px 12px;
  border-radius: 6px;
  font-size: 0.8rem;
  font-weight: 600;
  background-color: #f1f5f9;
  color: #475569;
  margin-bottom: 16px;
}

.pricing-card.featured .pricing-tag-subtle {
  background-color: var(--primary-blue-light);
  color: var(--primary-blue);
}

.pricing-plan-name {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 20px;
}

.pricing-price-wrap {
  display: flex;
  align-items: baseline;
  margin-bottom: 28px;
}

.pricing-currency {
  font-size: 1.4rem;
  font-weight: 800;
  margin-right: 6px;
}

.pricing-amount {
  font-size: 2.5rem;
  font-weight: 900;
  color: var(--text-main);
}

.pricing-unit {
  font-size: 0.95rem;
  color: var(--text-light);
  margin-left: 6px;
}

.pricing-features {
  list-style: none;
  margin-bottom: 36px;
  flex-grow: 1;
}

.pricing-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.92rem;
  color: var(--text-muted);
  margin-bottom: 14px;
}

.pricing-features li svg {
  width: 18px;
  height: 18px;
  fill: var(--primary-blue);
  flex-shrink: 0;
}

/* Audience Section */
.audience-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
  display: flex;
  gap: 20px;
  align-items: flex-start;
}

.audience-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: var(--primary-blue-light);
  color: var(--primary-blue);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  flex-shrink: 0;
}

/* Tutorial Section (Clash / Clash Party Focus) */
.tutorial-tabs {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-bottom: 40px;
  flex-wrap: wrap;
}

.tab-btn {
  padding: 10px 24px;
  border-radius: 30px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.2s ease;
}

.tab-btn.active, .tab-btn:hover {
  background: var(--primary-blue);
  color: #ffffff;
  border-color: var(--primary-blue);
}

.tab-content {
  display: none;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 40px;
  box-shadow: var(--shadow-card);
}

.tab-content.active {
  display: block;
}

.step-list {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.step-item {
  display: flex;
  gap: 20px;
  align-items: flex-start;
}

.step-num {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--primary-blue);
  color: #ffffff;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.step-body h4 {
  font-size: 1.1rem;
  margin-bottom: 6px;
}

/* Reviews Section */
.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.review-stars {
  color: #f59e0b;
  margin-bottom: 12px;
  font-size: 1.1rem;
}

.review-text {
  font-style: italic;
  margin-bottom: 20px;
  color: var(--text-muted);
  font-size: 0.95rem;
}

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

.avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--primary-blue-light);
  color: var(--primary-blue);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
}

/* FAQ Accordion */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
  max-width: 900px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: border-color 0.2s ease;
}

.faq-question {
  padding: 20px 24px;
  font-size: 1.1rem;
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  user-select: none;
}

.faq-toggle {
  font-size: 1.2rem;
  transition: transform 0.3s ease;
  color: var(--primary-blue);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  padding: 0 24px;
  color: var(--text-muted);
  line-height: 1.7;
}

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

.faq-item.active .faq-answer {
  max-height: 500px;
  padding: 0 24px 20px 24px;
}

/* Article Grid Section */
.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: all 0.3s ease;
}

.article-card:hover {
  transform: translateY(-4px);
  border-color: var(--primary-blue-border);
  box-shadow: var(--shadow-hover);
}

.article-meta {
  font-size: 0.85rem;
  color: var(--text-light);
  margin-bottom: 10px;
}

.article-title {
  font-size: 1.15rem;
  margin-bottom: 12px;
  line-height: 1.4;
}

.article-summary {
  font-size: 0.92rem;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.article-link {
  color: var(--primary-blue);
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
}

/* Article Detail Layout */
.article-page {
  padding: 60px 0 90px 0;
}

.breadcrumb {
  display: flex;
  gap: 8px;
  align-items: center;
  font-size: 0.9rem;
  color: var(--text-light);
  margin-bottom: 30px;
}

.breadcrumb a {
  color: var(--primary-blue);
}

.article-header {
  margin-bottom: 40px;
}

.article-header h1 {
  font-size: 2.4rem;
  margin-bottom: 16px;
}

.article-info-bar {
  display: flex;
  gap: 20px;
  font-size: 0.9rem;
  color: var(--text-light);
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border-color);
}

.article-content {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text-main);
}

.article-content h2 {
  font-size: 1.6rem;
  margin: 36px 0 16px 0;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--primary-blue-light);
}

.article-content h3 {
  font-size: 1.3rem;
  margin: 28px 0 12px 0;
}

.article-content p {
  margin-bottom: 20px;
}

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

.article-content li {
  margin-bottom: 8px;
}

.toc-box {
  background: var(--bg-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 24px;
  margin-bottom: 36px;
}

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

.toc-list {
  list-style: none;
  padding-left: 0;
}

.toc-list li {
  margin-bottom: 8px;
}

.toc-list a {
  color: var(--primary-blue);
  font-size: 0.95rem;
}

.cta-box {
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  color: #ffffff;
  border-radius: var(--radius-xl);
  padding: 40px;
  text-align: center;
  margin: 50px 0;
}

.cta-box h3 {
  color: #ffffff;
  font-size: 1.8rem;
  margin-bottom: 12px;
}

.cta-box p {
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: 24px;
}

/* Footer & Sitemap */
.footer {
  background: var(--bg-subtle);
  border-top: 1px solid var(--border-color);
  padding: 70px 0 30px 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 50px;
}

.footer-col h4 {
  font-size: 1.1rem;
  margin-bottom: 20px;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 10px;
}

.footer-links a {
  color: var(--text-muted);
  font-size: 0.92rem;
  transition: color 0.2s ease;
}

.footer-links a:hover {
  color: var(--primary-blue);
}

.footer-bottom {
  text-align: center;
  padding-top: 30px;
  border-top: 1px solid var(--border-color);
  font-size: 0.88rem;
  color: var(--text-light);
}

/* Mobile Responsive Adjustments */
@media (max-width: 992px) {
  .hero-grid { grid-template-columns: 1fr; gap: 40px; }
  .grid-3, .pricing-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .hero-title { font-size: 2.2rem; }
}

@media (max-width: 768px) {
  .mobile-toggle { display: block; }
  .nav-menu {
    position: fixed;
    top: 70px;
    left: 0;
    width: 100%;
    background: #ffffff;
    flex-direction: column;
    padding: 24px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    display: none;
  }
  .nav-menu.active { display: flex; }
  .grid-3, .grid-2, .grid-4, .pricing-grid { grid-template-columns: 1fr; }
  .hero-title { font-size: 1.8rem; }
  .section { padding: 50px 0; }
  .footer-grid { grid-template-columns: 1fr; }
}