/* CSS Variables for Premium Light Blue-White Theme */
:root {
  --bg-color: #f0f4f8;       /* Light white-blue base */
  --card-bg: rgba(255, 255, 255, 0.85); /* White glass card with high opacity for readability */
  --card-border: rgba(99, 102, 241, 0.08);
  --text-primary: #1e293b;   /* Dark gray-blue for contrast */
  --text-secondary: #475569; /* Medium gray-blue */
  --text-muted: #64748b;
  
  --primary: #4f46e5;       /* Indigo */
  --primary-glow: rgba(79, 70, 229, 0.08);
  --secondary: #9333ea;     /* Purple */
  --secondary-glow: rgba(147, 51, 234, 0.08);
  --accent: #0891b2;        /* Cyan */
  --accent-glow: rgba(8, 145, 178, 0.08);
  
  --btn-grad: linear-gradient(135deg, var(--primary), var(--secondary));
  --text-grad: linear-gradient(135deg, #7c3aed, #4f46e5, #0891b2);
  --border-radius: 16px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font-sans: 'Outfit', 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans CJK SC", sans-serif;
}

/* Base Reset */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background-image: url('images/bg.jpg');
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  background-attachment: fixed;
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
}

/* White-blue overlay for content readability */
body::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(240, 244, 248, 0.55);
  z-index: -1;
  pointer-events: none;
}

/* Container */
.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 15px;
  position: relative;
  z-index: 2;
}

/* Header & Navigation */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(240, 244, 248, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(99, 102, 241, 0.06);
}

.nav-wrapper {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 80px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  background: linear-gradient(135deg, #1e293b 30%, #475569 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

nav ul {
  display: flex;
  list-style: none;
  gap: 30px;
  align-items: center;
}

nav ul li a {
  color: var(--text-secondary);
  font-weight: 500;
}

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

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  border-radius: 9999px;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: var(--transition);
  border: none;
}

.btn-primary {
  background: var(--btn-grad);
  color: #fff;
  box-shadow: 0 4px 20px rgba(79, 70, 229, 0.2);
  position: relative;
  overflow: hidden;
}

.btn-primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.25), transparent);
  transform: translateX(-100%);
  transition: 0.6s;
}

.btn-primary:hover::before {
  transform: translateX(100%);
}

.btn-primary:hover {
  box-shadow: 0 6px 24px rgba(147, 51, 234, 0.3);
  transform: translateY(-2px);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.65);
  color: var(--text-primary);
  border: 1px solid rgba(99, 102, 241, 0.12);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.9);
  border-color: rgba(99, 102, 241, 0.24);
  transform: translateY(-2px);
}

.btn-sm {
  padding: 8px 18px;
  font-size: 0.85rem;
}

/* Hero Section */
.hero {
  padding: 100px 0 80px 0;
  text-align: center;
  position: relative;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(79, 70, 229, 0.06);
  border: 1px solid rgba(79, 70, 229, 0.12);
  color: var(--primary);
  padding: 6px 16px;
  border-radius: 9999px;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 24px;
}

.badge-dot {
  width: 6px;
  height: 6px;
  background-color: var(--primary);
  border-radius: 50%;
  animation: pulse 2s infinite;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -1.5px;
  margin-bottom: 24px;
  color: #0f172a;
}

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

.hero p {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 700px;
  margin: 0 auto 40px auto;
}

.hero-btns {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-bottom: 60px;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  max-width: 600px;
  margin: 0 auto;
  border-top: 1px solid rgba(99, 102, 241, 0.12);
  padding-top: 40px;
}

.stat-item h3 {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 5px;
}

.stat-item p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* Card glassmorphism - Light Mode */
.glass-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: 0 10px 30px -10px rgba(99, 102, 241, 0.05);
  padding: 30px;
  transition: var(--transition);
}

.glass-card:hover {
  border-color: rgba(79, 70, 229, 0.2);
  box-shadow: 0 20px 40px -15px rgba(99, 102, 241, 0.1);
  transform: translateY(-5px);
}

/* Features Section */
.features {
  padding: 80px 0;
}

.section-header {
  text-align: center;
  max-width: 600px;
  margin: 0 auto 60px auto;
}

.section-header h2 {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 16px;
  letter-spacing: -1px;
  color: #0f172a;
}

.section-header p {
  color: var(--text-secondary);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
}

.feature-icon {
  width: 50px;
  height: 50px;
  border-radius: 12px;
  background: rgba(79, 70, 229, 0.06);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  font-size: 1.5rem;
  margin-bottom: 20px;
}

.feature-card h3 {
  font-size: 1.3rem;
  margin-bottom: 12px;
  color: #0f172a;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* Pricing Section */
.pricing {
  padding: 80px 0;
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 30px;
  align-items: stretch;
}

.pricing-card {
  display: flex;
  flex-direction: column;
  position: relative;
  background: rgba(255, 255, 255, 0.8);
}

.pricing-card.featured {
  border-color: var(--primary);
  box-shadow: 0 15px 35px -10px rgba(79, 70, 229, 0.15);
  background: rgba(255, 255, 255, 0.92);
}

.pricing-card.featured::after {
  content: '推荐';
  position: absolute;
  top: -12px;
  right: 25px;
  background: var(--btn-grad);
  font-size: 0.75rem;
  font-weight: 700;
  color: #fff;
  padding: 4px 14px;
  border-radius: 9999px;
  letter-spacing: 0.5px;
}

.pricing-card h3 {
  font-size: 1.25rem;
  margin-bottom: 10px;
  color: #0f172a;
}

.price {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--primary);
  margin: 15px 0;
  display: flex;
  align-items: baseline;
}

.price span {
  font-size: 1rem;
  color: var(--text-secondary);
  font-weight: 400;
  margin-left: 5px;
}

.pricing-card p.desc {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 20px;
  min-height: 40px;
}

.pricing-features {
  list-style: none;
  margin-bottom: 30px;
  flex-grow: 1;
}

.pricing-features li {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.pricing-features li::before {
  content: '✓';
  color: var(--accent);
  font-weight: bold;
}

/* User Reviews Section */
.reviews {
  padding: 80px 0;
}

.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 30px;
}

.review-card {
  padding: 30px;
  background: rgba(255, 255, 255, 0.8);
}

.review-stars {
  color: #f59e0b;
  margin-bottom: 15px;
}

.review-text {
  font-style: italic;
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 25px;
}

.user-info {
  display: flex;
  align-items: center;
  gap: 15px;
}

.avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--btn-grad);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  color: #fff;
}

.user-details h4 {
  font-size: 0.95rem;
  color: #0f172a;
}

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

/* FAQ Section */
.faq {
  padding: 80px 0;
}

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

.faq-item {
  margin-bottom: 15px;
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius);
  background: rgba(255, 255, 255, 0.7);
  overflow: hidden;
  transition: var(--transition);
}

.faq-item:hover {
  border-color: rgba(79, 70, 229, 0.15);
  background: rgba(255, 255, 255, 0.85);
}

.faq-question {
  padding: 22px 30px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  user-select: none;
}

.faq-question h3 {
  font-size: 1.1rem;
  font-weight: 600;
  color: #0f172a;
  transition: var(--transition);
}

.faq-question .icon {
  font-size: 1.2rem;
  color: var(--text-secondary);
  transition: var(--transition);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out;
  padding: 0 30px;
}

.faq-answer p {
  padding-bottom: 22px;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.faq-item.active {
  border-color: rgba(79, 70, 229, 0.3);
  background: rgba(255, 255, 255, 0.9);
}

.faq-item.active .faq-question h3 {
  color: var(--primary);
}

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

.faq-item.active .faq-answer {
  max-height: 300px;
}

/* Blog / Articles Grid Section */
.articles-section {
  padding: 80px 0;
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 30px;
}

.article-card {
  height: 100%;
  display: flex;
  flex-direction: column;
}

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

.article-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 12px;
  display: flex;
  gap: 15px;
}

.article-card h3 {
  font-size: 1.25rem;
  margin-bottom: 12px;
  line-height: 1.4;
  color: #0f172a;
}

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

.article-excerpt {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 20px;
  flex-grow: 1;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.read-more {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--primary);
}

.read-more:hover {
  color: var(--secondary);
  gap: 8px;
}

/* Article Template Layout */
.article-page {
  padding: 50px 0 100px 0;
}

.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 40px;
}

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

.article-layout {
  display: grid;
  grid-template-columns: 8fr 4fr;
  gap: 40px;
}

.article-content {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius);
  box-shadow: 0 10px 30px -10px rgba(99, 102, 241, 0.04);
  padding: 40px;
}

.article-header {
  border-bottom: 1px solid rgba(99, 102, 241, 0.08);
  padding-bottom: 30px;
  margin-bottom: 30px;
}

.article-header h1 {
  font-size: 2.25rem;
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 20px;
  color: #0f172a;
}

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

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

.article-body h2 {
  font-size: 1.5rem;
  margin-top: 40px;
  margin-bottom: 16px;
  color: #0f172a;
  border-left: 4px solid var(--primary);
  padding-left: 15px;
}

.article-body p {
  margin-bottom: 24px;
}

.article-body ul, .article-body ol {
  margin-left: 20px;
  margin-bottom: 24px;
}

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

.article-body blockquote {
  border-left: 4px solid var(--accent);
  background: rgba(8, 145, 178, 0.04);
  padding: 20px;
  margin: 30px 0;
  border-radius: 0 8px 8px 0;
  font-style: italic;
  color: var(--text-secondary);
}

/* Sidebar styling */
.article-sidebar {
  display: flex;
  flex-direction: column;
  gap: 30px;
}

.sidebar-widget {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--border-radius);
  box-shadow: 0 10px 30px -10px rgba(99, 102, 241, 0.04);
  padding: 30px;
}

.sidebar-widget h3 {
  font-size: 1.15rem;
  margin-bottom: 20px;
  color: #0f172a;
  border-bottom: 1px solid rgba(99, 102, 241, 0.08);
  padding-bottom: 10px;
}

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

.sidebar-links li {
  margin-bottom: 15px;
  font-size: 0.95rem;
}

.sidebar-links li a {
  display: flex;
  flex-direction: column;
}

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

.sidebar-links li a span {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.cta-widget {
  background: radial-gradient(circle at top right, rgba(79, 70, 229, 0.06) 0%, transparent 60%), var(--card-bg);
  text-align: center;
  border-color: rgba(79, 70, 229, 0.2);
}

.cta-widget p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 20px;
}

/* Footer */
footer {
  background: #f8fafc;
  border-top: 1px solid rgba(99, 102, 241, 0.08);
  padding: 80px 0 40px 0;
  color: var(--text-secondary);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 50px;
  margin-bottom: 60px;
}

.footer-brand h2 {
  font-size: 1.5rem;
  font-weight: 800;
  color: #0f172a;
  margin-bottom: 15px;
}

.footer-brand p {
  font-size: 0.9rem;
  max-width: 300px;
  margin-bottom: 20px;
}

.footer-links h4 {
  font-size: 1rem;
  color: #0f172a;
  margin-bottom: 20px;
}

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

.footer-links ul li {
  margin-bottom: 12px;
  font-size: 0.9rem;
}

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

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid rgba(99, 102, 241, 0.08);
  padding-top: 40px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Animations */
@keyframes pulse {
  0% {
    transform: scale(0.95);
    box-shadow: 0 0 0 0 rgba(79, 70, 229, 0.3);
  }
  70% {
    transform: scale(1);
    box-shadow: 0 0 0 10px rgba(79, 70, 229, 0);
  }
  100% {
    transform: scale(0.95);
    box-shadow: 0 0 0 0 rgba(79, 70, 229, 0);
  }
}

/* Responsive adjustments */
@media (max-width: 992px) {
  .hero h1 {
    font-size: 2.75rem;
  }
  .article-layout {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  header {
    padding: 10px 0;
  }
  .nav-wrapper {
    height: auto;
    flex-direction: column;
    gap: 15px;
  }
  nav ul {
    gap: 15px;
    flex-wrap: wrap;
    justify-content: center;
  }
  .hero {
    padding: 60px 0 40px 0;
  }
  .hero h1 {
    font-size: 2.25rem;
  }
  .hero-btns {
    flex-direction: column;
    align-items: center;
    gap: 15px;
  }
  .btn {
    width: 100%;
    max-width: 320px;
  }
  .hero-stats {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 30px;
  }
  .footer-bottom {
    flex-direction: column;
    gap: 15px;
    text-align: center;
  }
  .article-content {
    padding: 20px;
  }
  .article-header h1 {
    font-size: 1.75rem;
  }
}