/* 浅青色主题样式 (Light Cyan Theme) */
:root {
  --primary-color: #00bcd4; /* Cyan */
  --primary-light: #e0f7fa; /* Light Cyan */
  --primary-dark: #0097a7; /* Dark Cyan */
  --secondary-color: #ff4081; /* Pink accent */
  --text-main: #333333;
  --text-muted: #666666;
  --bg-color: #f5fcfc; /* Very light cyan/grey background */
  --bg-card: #ffffff;
  --border-radius: 12px;
  --transition: all 0.3s ease;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.6;
  overflow-x: hidden;
}

/* 动态背景点缀 (Dynamic background elements) */
.bg-elements {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
}

.circle {
  position: absolute;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(0, 188, 212, 0.15) 0%, rgba(0, 188, 212, 0) 70%);
  animation: float 20s infinite ease-in-out;
}

.circle-1 {
  width: 400px;
  height: 400px;
  top: -100px;
  left: -100px;
  animation-delay: 0s;
}

.circle-2 {
  width: 600px;
  height: 600px;
  bottom: -200px;
  right: -100px;
  animation-delay: -5s;
}

.circle-3 {
  width: 300px;
  height: 300px;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation-delay: -10s;
}

@keyframes float {
  0% { transform: translateY(0) scale(1); opacity: 0.8; }
  50% { transform: translateY(-30px) scale(1.05); opacity: 1; }
  100% { transform: translateY(0) scale(1); opacity: 0.8; }
}

/* Header / Hero Section */
header {
  padding: 100px 20px;
  text-align: center;
  position: relative;
}

h1 {
  font-size: 3rem;
  color: var(--primary-dark);
  margin-bottom: 20px;
  font-weight: 800;
}

.subtitle {
  font-size: 1.2rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto 40px;
}

.cta-button {
  display: inline-block;
  background-color: var(--primary-color);
  color: #fff;
  padding: 15px 40px;
  border-radius: 30px;
  text-decoration: none;
  font-size: 1.2rem;
  font-weight: bold;
  box-shadow: 0 4px 15px rgba(0, 188, 212, 0.4);
  transition: var(--transition);
}

.cta-button:hover {
  background-color: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 188, 212, 0.6);
}

/* Sections */
section {
  padding: 80px 20px;
  max-width: 1200px;
  margin: 0 auto;
}

.section-title {
  text-align: center;
  font-size: 2.5rem;
  color: var(--primary-dark);
  margin-bottom: 50px;
}

/* Pricing Grid */
.pricing-grid {
  display: flex;
  justify-content: center;
  gap: 30px;
  flex-wrap: wrap;
}

.pricing-card {
  background: var(--bg-card);
  border-radius: var(--border-radius);
  padding: 40px 30px;
  width: 350px;
  text-align: center;
  box-shadow: 0 10px 30px rgba(0,0,0,0.05);
  border: 1px solid rgba(0, 188, 212, 0.1);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.pricing-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 20px 40px rgba(0, 188, 212, 0.15);
  border-color: var(--primary-color);
}

.pricing-card.highlight {
  border: 2px solid var(--primary-color);
  transform: scale(1.05);
  box-shadow: 0 20px 40px rgba(0, 188, 212, 0.2);
}

.pricing-card.highlight:hover {
  transform: scale(1.05) translateY(-5px);
}

.pricing-card.highlight::before {
  content: '热门选择';
  position: absolute;
  top: 15px;
  right: -35px;
  background: var(--primary-color);
  color: #fff;
  padding: 5px 40px;
  transform: rotate(45deg);
  font-size: 0.8rem;
  font-weight: bold;
}

.plan-name {
  font-size: 1.5rem;
  color: var(--text-main);
  margin-bottom: 15px;
  font-weight: 600;
}

.plan-price {
  font-size: 3rem;
  color: var(--primary-dark);
  font-weight: 800;
  margin-bottom: 10px;
}

.plan-price span {
  font-size: 1rem;
  color: var(--text-muted);
  font-weight: normal;
}

.plan-desc {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 30px;
}

.plan-features {
  list-style: none;
  margin-bottom: 40px;
  text-align: left;
}

.plan-features li {
  padding: 10px 0;
  border-bottom: 1px solid rgba(0,0,0,0.05);
  color: var(--text-main);
  font-size: 0.95rem;
  display: flex;
  align-items: center;
}

.plan-features li::before {
  content: '✓';
  color: var(--primary-color);
  margin-right: 10px;
  font-weight: bold;
}

.plan-btn {
  display: block;
  width: 100%;
  padding: 15px;
  border-radius: var(--border-radius);
  text-decoration: none;
  font-weight: bold;
  border: 2px solid var(--primary-color);
  color: var(--primary-color);
  transition: var(--transition);
}

.plan-btn:hover, .pricing-card.highlight .plan-btn {
  background: var(--primary-color);
  color: #fff;
}

/* Articles Section */
.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}

.article-card {
  background: var(--bg-card);
  padding: 25px;
  border-radius: var(--border-radius);
  box-shadow: 0 5px 15px rgba(0,0,0,0.05);
  transition: var(--transition);
  text-decoration: none;
  color: inherit;
  border: 1px solid rgba(0,0,0,0.02);
}

.article-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0, 188, 212, 0.1);
  border-color: var(--primary-light);
}

.article-title {
  font-size: 1.2rem;
  color: var(--primary-dark);
  margin-bottom: 10px;
  font-weight: 600;
}

.article-desc {
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Reviews Section */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
}

.review-card {
  background: var(--bg-card);
  padding: 30px;
  border-radius: var(--border-radius);
  box-shadow: 0 5px 15px rgba(0,0,0,0.05);
  position: relative;
}

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

.review-author {
  font-weight: bold;
  color: var(--primary-dark);
}

/* FAQ Section */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-card);
  margin-bottom: 15px;
  border-radius: var(--border-radius);
  box-shadow: 0 5px 15px rgba(0,0,0,0.03);
  padding: 20px;
}

.faq-q {
  font-weight: bold;
  font-size: 1.1rem;
  color: var(--primary-dark);
  margin-bottom: 10px;
}

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

/* Footer */
footer {
  text-align: center;
  padding: 40px 20px;
  background: rgba(0, 188, 212, 0.05);
  color: var(--text-muted);
  margin-top: 50px;
}

@media (max-width: 768px) {
  .pricing-card.highlight {
    transform: none;
  }
  .pricing-card.highlight:hover {
    transform: translateY(-5px);
  }
}