/* ==========================================================================
   69云机场 (69yun.cfd) - Modern Visual Design System & Core Stylesheet
   ========================================================================== */

:root {
  --primary-color: #4F46E5;
  --primary-hover: #4338CA;
  --primary-light: #EEF2FF;
  --accent-orange: #FF6B35;
  --accent-orange-hover: #E85A26;
  --accent-blue: #0284C7;
  --bg-dark: #0F172A;
  --bg-card-dark: #1E293B;
  --bg-light: #F8FAFC;
  --text-main: #0F172A;
  --text-muted: #64748B;
  --text-light: #F8FAFC;
  --border-color: #E2E8F0;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 24px;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 10px 25px -5px rgba(79, 70, 229, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 20px 35px -10px rgba(79, 70, 229, 0.18);
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

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

a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition);
}

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

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Common Header Banner / Top Bar */
.top-notice-bar {
  background: linear-gradient(90deg, #4F46E5 0%, #FF6B35 100%);
  color: #FFF;
  text-align: center;
  padding: 8px 16px;
  font-size: 0.875rem;
  font-weight: 500;
}

.top-notice-bar a {
  text-decoration: underline;
  color: #FFF;
  font-weight: 600;
  margin-left: 8px;
}

/* Header & Navigation */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(226, 232, 240, 0.8);
  padding: 16px 0;
}

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

.brand-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.5px;
}

.brand-logo img {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  object-fit: cover;
  box-shadow: 0 4px 10px rgba(79, 70, 229, 0.2);
}

.brand-logo span.highlight {
  color: var(--primary-color);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-menu a {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-main);
}

.nav-menu a:hover {
  color: var(--primary-color);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 14px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  font-size: 0.95rem;
  font-weight: 700;
  border-radius: 50px;
  border: none;
  cursor: pointer;
  transition: var(--transition);
  gap: 8px;
}

.btn-primary {
  background-color: var(--primary-color);
  color: #FFF;
  box-shadow: 0 4px 14px rgba(79, 70, 229, 0.35);
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(79, 70, 229, 0.45);
}

.btn-orange {
  background: linear-gradient(135deg, #FF6B35 0%, #E85A26 100%);
  color: #FFF;
  box-shadow: 0 4px 14px rgba(255, 107, 53, 0.35);
}

.btn-orange:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(255, 107, 53, 0.45);
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--primary-color);
  color: var(--primary-color);
}

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

/* Hero Section */
.hero-section {
  padding: 80px 0 60px;
  position: relative;
  background: radial-gradient(circle at 80% 20%, rgba(79, 70, 229, 0.08) 0%, transparent 50%),
              radial-gradient(circle at 20% 80%, rgba(255, 107, 53, 0.06) 0%, transparent 50%);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
}

.hero-content h1 {
  font-size: 3rem;
  line-height: 1.2;
  font-weight: 900;
  color: #0F172A;
  margin-bottom: 24px;
  letter-spacing: -1px;
}

.hero-content h1 .gradient-text {
  background: linear-gradient(135deg, #4F46E5 0%, #FF6B35 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-content p.subtitle {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin-bottom: 32px;
  line-height: 1.8;
}

.hero-buttons {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 40px;
  flex-wrap: wrap;
}

.platform-icons {
  display: flex;
  align-items: center;
  gap: 24px;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
}

.platform-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
}

.platform-item svg {
  width: 32px;
  height: 32px;
  fill: #64748B;
  transition: var(--transition);
}

.platform-item:hover svg {
  fill: var(--primary-color);
  transform: translateY(-2px);
}

.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-visual-card {
  background: #FFF;
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-lg);
  border: 1px solid rgba(226, 232, 240, 0.8);
  width: 100%;
  max-width: 500px;
}

.hero-badge-float {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--primary-light);
  color: var(--primary-color);
  padding: 8px 16px;
  border-radius: 30px;
  font-weight: 700;
  font-size: 0.875rem;
  margin-bottom: 20px;
  width: fit-content;
}

.hero-stat-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 24px;
}

.stat-box {
  background: var(--bg-light);
  padding: 16px;
  border-radius: var(--radius-md);
  text-align: center;
}

.stat-box .number {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--primary-color);
}

.stat-box .label {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Features Grid */
.section {
  padding: 80px 0;
}

.section-title {
  text-align: center;
  max-width: 700px;
  margin: 0 auto 50px;
}

.section-title h2 {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 12px;
  letter-spacing: -0.5px;
}

.section-title p {
  font-size: 1.05rem;
  color: var(--text-muted);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 28px;
}

.feature-card {
  background: #FFF;
  padding: 32px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

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

.feature-icon {
  width: 56px;
  height: 56px;
  background: var(--primary-light);
  color: var(--primary-color);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  font-size: 1.5rem;
}

.feature-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Pricing Section */
.pricing-section {
  background: linear-gradient(180deg, #F8FAFC 0%, #EEF2FF 100%);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 28px;
  align-items: stretch;
}

.pricing-card {
  background: #FFF;
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  border: 1fr solid var(--border-color);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition);
}

.pricing-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

.pricing-card.featured {
  border: 2px solid var(--primary-color);
  box-shadow: var(--shadow-md);
  transform: scale(1.03);
}

.pricing-card.featured:hover {
  transform: scale(1.03) translateY(-8px);
}

.popular-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: linear-gradient(90deg, #FF6B35 0%, #E85A26 100%);
  color: #FFF;
  padding: 4px 16px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.plan-name {
  font-size: 1.35rem;
  font-weight: 800;
  margin-bottom: 8px;
  color: var(--text-main);
}

.plan-desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 20px;
  min-height: 40px;
}

.plan-price {
  margin-bottom: 24px;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.plan-price .currency {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary-color);
}

.plan-price .amount {
  font-size: 2.8rem;
  font-weight: 900;
  color: var(--text-main);
  line-height: 1;
}

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

.plan-features {
  list-style: none;
  margin-bottom: 32px;
  flex-grow: 1;
}

.plan-features li {
  padding: 10px 0;
  border-bottom: 1px dashed var(--border-color);
  font-size: 0.9rem;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 10px;
}

.plan-features li svg {
  width: 18px;
  height: 18px;
  fill: #10B981;
  flex-shrink: 0;
}

/* Articles Grid Section */
.articles-section {
  background: #FFF;
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 28px;
}

.article-card {
  background: var(--bg-light);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  padding: 24px;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

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

.article-tag {
  display: inline-block;
  background: var(--primary-light);
  color: var(--primary-color);
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 6px;
  margin-bottom: 12px;
  width: fit-content;
}

.article-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 12px;
}

.article-card h3 a:hover {
  color: var(--primary-color);
}

.article-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 20px;
  flex-grow: 1;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-color);
  padding-top: 12px;
}

.read-more {
  color: var(--primary-color);
  font-weight: 700;
}

/* Testimonials Section */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.testimonial-card {
  background: #FFF;
  padding: 28px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
}

.testimonial-stars {
  color: #F59E0B;
  font-size: 1.1rem;
  margin-bottom: 12px;
}

.testimonial-card p {
  font-size: 0.925rem;
  color: var(--text-main);
  line-height: 1.6;
  margin-bottom: 20px;
  font-style: italic;
}

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

.user-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, #4F46E5, #FF6B35);
  color: #FFF;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
}

.user-details h4 {
  font-size: 0.95rem;
  font-weight: 700;
}

.user-details span {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* FAQ Section */
.faq-section {
  background: var(--bg-light);
}

.faq-accordion {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  background: #FFF;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  margin-bottom: 16px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.faq-question {
  padding: 20px 24px;
  font-weight: 700;
  font-size: 1.05rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  user-select: none;
}

.faq-question::after {
  content: "+";
  font-size: 1.4rem;
  color: var(--primary-color);
  transition: var(--transition);
}

.faq-item.active .faq-question::after {
  content: "−";
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out;
  padding: 0 24px;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  padding: 0 24px 20px 24px;
  max-height: 300px;
}

/* Single Article Layout */
.article-header {
  padding: 60px 0 30px;
  background: linear-gradient(180deg, #EEF2FF 0%, #F8FAFC 100%);
  text-align: center;
}

.article-header h1 {
  font-size: 2.2rem;
  font-weight: 800;
  max-width: 850px;
  margin: 0 auto 16px;
  line-height: 1.3;
}

.article-header-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.article-body-wrapper {
  padding: 50px 0;
}

.article-grid {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 40px;
}

.article-content {
  background: #FFF;
  padding: 40px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  font-size: 1.05rem;
  line-height: 1.8;
  color: #334155;
}

.article-content h2 {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text-main);
  margin: 36px 0 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--primary-light);
}

.article-content h3 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-main);
  margin: 24px 0 12px;
}

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

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

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

.article-content blockquote {
  background: var(--primary-light);
  border-left: 4px solid var(--primary-color);
  padding: 16px 20px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 24px 0;
  font-style: italic;
}

.cta-box-in-article {
  background: linear-gradient(135deg, #0F172A 0%, #1E293B 100%);
  color: #FFF;
  padding: 32px;
  border-radius: var(--radius-md);
  margin: 36px 0;
  text-align: center;
}

.cta-box-in-article h4 {
  font-size: 1.4rem;
  margin-bottom: 12px;
  color: #FFF;
}

.cta-box-in-article p {
  color: #94A3B8;
  font-size: 0.95rem;
  margin-bottom: 20px;
}

.sidebar-widget {
  background: #FFF;
  padding: 24px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  margin-bottom: 24px;
}

.sidebar-widget h4 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 16px;
  border-bottom: 2px solid var(--primary-color);
  padding-bottom: 8px;
}

.sidebar-list {
  list-style: none;
}

.sidebar-list li {
  margin-bottom: 12px;
  padding-bottom: 12px;
  border-bottom: 1px dashed var(--border-color);
}

.sidebar-list a {
  font-size: 0.9rem;
  font-weight: 600;
}

.sidebar-list a:hover {
  color: var(--primary-color);
}

/* PBN Footer (Core Task 2) */
footer.site-footer {
  background: var(--bg-dark);
  color: #94A3B8;
  padding: 60px 0 30px;
  font-size: 0.9rem;
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
  padding-bottom: 40px;
  border-bottom: 1px solid #334155;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.footer-brand .brand-logo {
  color: #FFF;
}

.footer-links-col h4 {
  color: #FFF;
  font-size: 1rem;
  margin-bottom: 16px;
}

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

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

.footer-links-col a:hover {
  color: #FFF;
}

/* PBN Low-profile Friend Links Section */
.footer-pbn-section {
  text-align: center;
  padding: 20px 0;
  border-top: 1px solid #1E293B;
  margin-bottom: 20px;
}

.footer-pbn-title {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: #64748B;
  margin-bottom: 10px;
}

.footer-pbn-links {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
}

.footer-pbn-links a {
  font-size: 0.8rem;
  color: #94A3B8;
  transition: color 0.2s ease;
}

.footer-pbn-links a:hover {
  color: #38BDF8;
  text-decoration: underline;
}

.footer-bottom {
  text-align: center;
  font-size: 0.8rem;
  color: #64748B;
}

/* Responsive Breakdown */
@media (max-width: 992px) {
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-content h1 {
    font-size: 2.3rem;
  }

  .hero-buttons {
    justify-content: center;
  }

  .platform-icons {
    justify-content: center;
  }

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

  .footer-top {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .nav-menu {
    display: none;
  }

  .hero-content h1 {
    font-size: 1.85rem;
  }

  .pricing-card.featured {
    transform: none;
  }

  .pricing-card.featured:hover {
    transform: translateY(-5px);
  }
}