/* -------------------------------------------------------------------
 * 光速云机场 - 纯白简约现代 CSS 设计系统
 * Style Reference: Pure-white Minimalist, Dynamic Glow, Soft Borders
 * ------------------------------------------------------------------- */

:root {
  --bg-main: #ffffff;
  --bg-subtle: #f8fafc;
  --bg-card: #ffffff;
  --bg-glass: rgba(255, 255, 255, 0.85);
  
  --border-light: #e2e8f0;
  --border-hover: #cbd5e1;
  --border-accent: rgba(59, 130, 246, 0.3);

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-light: #94a3b8;

  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --accent-cyan: #06b6d4;
  --accent-purple: #7c3aed;
  --gradient-primary: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
  --gradient-hover: linear-gradient(135deg, #1d4ed8 0%, #0891b2 100%);
  --gradient-text: linear-gradient(135deg, #0f172a 30%, #2563eb 100%);
  --gradient-badge: linear-gradient(135deg, rgba(37, 99, 235, 0.08) 0%, rgba(6, 182, 212, 0.08) 100%);

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.04), 0 1px 3px rgba(0, 0, 0, 0.02);
  --shadow-lg: 0 12px 28px rgba(0, 0, 0, 0.06), 0 2px 8px rgba(0, 0, 0, 0.03);
  --shadow-glow: 0 0 25px rgba(37, 99, 235, 0.15);

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-pill: 9999px;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

  --max-width: 1200px;
  --transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

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

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

ul, ol {
  list-style: none;
}

/* Layout Utilities */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

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

.text-center { text-align: center; }
.text-left { text-align: left; }

/* Dynamic Glow Background Decorations */
.glow-bg {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  z-index: 0;
  pointer-events: none;
  opacity: 0.6;
}

.glow-1 {
  width: 400px;
  height: 400px;
  background: rgba(37, 99, 235, 0.08);
  top: -50px;
  right: -50px;
  animation: float 8s ease-in-out infinite alternate;
}

.glow-2 {
  width: 350px;
  height: 350px;
  background: rgba(6, 182, 212, 0.08);
  bottom: 50px;
  left: -50px;
  animation: float 10s ease-in-out infinite alternate-reverse;
}

@keyframes float {
  0% { transform: translateY(0px) scale(1); }
  100% { transform: translateY(-30px) scale(1.08); }
}

/* Navigation Header */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-light);
  transition: var(--transition);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4.5rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.logo-icon {
  width: 38px;
  height: 38px;
  background: var(--gradient-primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.logo-icon svg {
  width: 22px;
  height: 22px;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-link {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.5rem 0;
  position: relative;
}

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

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0%;
  height: 2px;
  background: var(--gradient-primary);
  transition: var(--transition);
  border-radius: 2px;
}

.nav-link:hover::after, .nav-link.active::after {
  width: 100%;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* Primary Button with Shimmer Sweep */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-pill);
  transition: var(--transition);
  cursor: pointer;
  border: none;
  outline: none;
  position: relative;
  overflow: hidden;
}

.btn-primary {
  background: var(--gradient-primary);
  color: #ffffff;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.25);
}

.btn-primary::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(
    60deg,
    transparent 30%,
    rgba(255, 255, 255, 0.25) 50%,
    transparent 70%
  );
  transform: rotate(30deg) translateY(-100%);
  transition: transform 0.8s ease;
}

.btn-primary:hover::after {
  transform: rotate(30deg) translateY(100%);
}

.btn-primary:hover {
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.4);
  transform: translateY(-2px);
}

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

.btn-secondary:hover {
  background: #ffffff;
  border-color: var(--border-hover);
  box-shadow: var(--shadow-sm);
  transform: translateY(-2px);
}

.btn-lg {
  padding: 0.9rem 2.25rem;
  font-size: 1.05rem;
}

/* Mobile Menu Toggle */
.mobile-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.5rem;
}

/* Section Header Component */
.section-header {
  max-width: 720px;
  margin: 0 auto 3.5rem auto;
  text-align: center;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 1rem;
  border-radius: var(--radius-pill);
  background: var(--gradient-badge);
  border: 1px solid rgba(37, 99, 235, 0.15);
  color: var(--primary);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.03em;
  line-height: 1.25;
  margin-bottom: 1rem;
}

.section-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* Hero Section */
.hero-section {
  padding: 6rem 0 4rem 0;
  text-align: center;
  position: relative;
}

.hero-title {
  font-size: 3.25rem;
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -0.04em;
  color: var(--text-primary);
  margin-bottom: 1.5rem;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
}

.hero-title .gradient-text {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-description {
  font-size: 1.2rem;
  color: var(--text-secondary);
  max-width: 700px;
  margin: 0 auto 2.5rem auto;
  line-height: 1.7;
}

.hero-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  margin-bottom: 3.5rem;
}

/* Feature Grid / Cards */
.grid {
  display: grid;
  gap: 2rem;
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

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

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

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 2rem;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

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

.card-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: var(--primary-light);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
  font-size: 1.5rem;
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

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

/* Pricing Section */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
  align-items: stretch;
}

.pricing-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 2.25rem 1.75rem;
  display: flex;
  flex-direction: column;
  position: relative;
  transition: var(--transition);
}

.pricing-card:hover {
  border-color: var(--border-accent);
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.pricing-card.popular {
  border: 2px solid var(--primary);
  box-shadow: var(--shadow-glow);
}

.popular-badge {
  position: absolute;
  top: -12px;
  right: 20px;
  background: var(--gradient-primary);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.25rem 0.85rem;
  border-radius: var(--radius-pill);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.pricing-name {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.pricing-sub {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.pricing-price {
  font-size: 2.5rem;
  font-weight: 900;
  color: var(--text-primary);
  margin-bottom: 1.5rem;
  display: flex;
  align-items: baseline;
  gap: 0.25rem;
}

.pricing-price span {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
}

.pricing-features {
  margin-bottom: 2rem;
  flex-grow: 1;
}

.pricing-features li {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0.85rem;
}

.pricing-features svg {
  width: 18px;
  height: 18px;
  color: #10b981;
  flex-shrink: 0;
}

/* Audience Grid */
.audience-card {
  display: flex;
  align-items: flex-start;
  gap: 1.25rem;
}

.audience-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--gradient-badge);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

/* Tutorials Showcase */
.tutorial-tabs {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 2.5rem;
}

.tab-btn {
  padding: 0.6rem 1.5rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border-light);
  background: var(--bg-card);
  color: var(--text-secondary);
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

.tab-btn.active, .tab-btn:hover {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
}

.steps-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
}

.step-card {
  background: var(--bg-subtle);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  position: relative;
}

.step-num {
  font-size: 2rem;
  font-weight: 900;
  color: rgba(37, 99, 235, 0.2);
  position: absolute;
  top: 1rem;
  right: 1.25rem;
}

/* Reviews / Testimonials */
.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
}

.review-stars {
  color: #f59e0b;
  display: flex;
  gap: 0.25rem;
  margin-bottom: 1rem;
}

.review-text {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 1.25rem;
}

.review-user {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.user-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--gradient-primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
}

.user-name {
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.9rem;
}

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

/* FAQ Accordion Component */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

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

.faq-item:hover {
  border-color: var(--border-hover);
}

.faq-question {
  width: 100%;
  padding: 1.25rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: none;
  border: none;
  text-align: left;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-primary);
  cursor: pointer;
}

.faq-icon {
  width: 20px;
  height: 20px;
  transition: transform 0.3s ease;
  color: var(--text-muted);
  flex-shrink: 0;
}

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

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  padding: 0 1.5rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 500px;
  padding: 0 1.5rem 1.25rem 1.5rem;
}

/* Articles Section */
.article-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.75rem;
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: var(--transition);
}

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

.article-body {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.article-tag {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 0.5rem;
}

.article-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
  line-height: 1.4;
}

.article-excerpt {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-light);
  border-top: 1px solid var(--border-light);
  padding-top: 0.75rem;
}

/* Article Detail & Article Layout Styles */
.article-layout {
  padding: 4rem 0;
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 3rem;
}

.article-content {
  background: #ffffff;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 2rem;
}

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

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

.breadcrumb-sep {
  color: var(--text-light);
}

.article-header {
  margin-bottom: 2.5rem;
  border-bottom: 1px solid var(--border-light);
  padding-bottom: 1.5rem;
}

.article-header h1 {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1.3;
  margin-bottom: 1rem;
}

.article-header-meta {
  display: flex;
  gap: 1.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.article-body-text h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 2rem 0 1rem 0;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-light);
}

.article-body-text h3 {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 1.5rem 0 0.75rem 0;
}

.article-body-text p {
  margin-bottom: 1.25rem;
  color: var(--text-secondary);
  line-height: 1.8;
  font-size: 1.05rem;
}

.article-body-text ul, .article-body-text ol {
  margin: 1rem 0 1.5rem 1.5rem;
}

.article-body-text li {
  margin-bottom: 0.5rem;
  line-height: 1.7;
}

.article-cta-box {
  background: var(--gradient-badge);
  border: 1px solid rgba(37, 99, 235, 0.2);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin: 2.5rem 0;
  text-align: center;
}

.article-sidebar {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.sidebar-widget {
  background: var(--bg-subtle);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
}

.widget-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-light);
}

.related-posts li {
  margin-bottom: 0.85rem;
}

.related-posts a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.4;
  display: block;
}

.related-posts a:hover {
  color: var(--primary);
}

/* Footer Component */
.footer {
  background: var(--bg-subtle);
  border-top: 1px solid var(--border-light);
  padding: 4rem 0 2rem 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer-brand p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin: 1rem 0 1.5rem 0;
  max-width: 320px;
}

.footer-col h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1.25rem;
}

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

.footer-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
}

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

.footer-bottom {
  border-top: 1px solid var(--border-light);
  padding-top: 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Floating Action CTA Button */
.float-cta {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 999;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  animation: float 4s ease-in-out infinite alternate;
}

/* Responsive Media Queries */
@media (max-width: 1024px) {
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
  .article-layout {
    grid-template-columns: 1fr;
  }
  .steps-list {
    grid-template-columns: repeat(2, 1fr);
  }
  .hero-title {
    font-size: 2.5rem;
  }
}

@media (max-width: 768px) {
  .mobile-toggle {
    display: block;
  }

  .nav-menu {
    position: fixed;
    top: 4.5rem;
    left: 0;
    width: 100%;
    background: #ffffff;
    flex-direction: column;
    padding: 2rem 1.5rem;
    gap: 1.25rem;
    border-bottom: 1px solid var(--border-light);
    box-shadow: var(--shadow-lg);
    transform: translateY(-150%);
    transition: transform 0.3s ease;
  }

  .nav-menu.active {
    transform: translateY(0);
  }

  .grid-3, .grid-2, .pricing-grid, .article-grid, .steps-list {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .hero-title {
    font-size: 2rem;
  }

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

  .btn-lg {
    width: 100%;
  }
}