:root {
  --bg-color: #0b0f19;
  --surface-color: #1a2235;
  --surface-hover: #242f46;
  --text-primary: #ffffff;
  --text-secondary: #94a3b8;
  --accent-color: #6366f1;
  --accent-hover: #4f46e5;
  --success-color: #10b981;
  --highlight-color: #f59e0b;
  --border-color: rgba(255, 255, 255, 0.1);
  --card-border-radius: 16px;
  --btn-border-radius: 8px;
  --transition-speed: 0.3s;
}

* {
  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-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent-color);
  text-decoration: none;
  transition: color var(--transition-speed) ease;
}

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

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header & Hero */
header {
  padding: 20px 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 24px;
  font-weight: 800;
  background: linear-gradient(135deg, #a855f7, #6366f1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero {
  text-align: center;
  padding: 80px 0;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, rgba(99, 102, 241, 0.15) 0%, rgba(11, 15, 25, 0) 70%);
  z-index: -1;
  pointer-events: none;
}

.hero h1 {
  font-size: 48px;
  margin-bottom: 20px;
  line-height: 1.2;
}

.hero p {
  font-size: 18px;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 40px;
}

.btn {
  display: inline-block;
  padding: 12px 28px;
  background-color: var(--accent-color);
  color: var(--text-primary);
  border-radius: var(--btn-border-radius);
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all var(--transition-speed) ease;
  text-align: center;
}

.btn:hover {
  background-color: var(--accent-hover);
  transform: translateY(-2px);
  box-shadow: 0 10px 20px rgba(99, 102, 241, 0.3);
}

.btn-secondary {
  background-color: transparent;
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background-color: rgba(255, 255, 255, 0.05);
  box-shadow: none;
}

/* Pricing */
.pricing {
  padding: 60px 0;
}

.section-title {
  text-align: center;
  font-size: 32px;
  margin-bottom: 50px;
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 30px;
  align-items: stretch;
}

.pricing-card {
  background-color: var(--surface-color);
  border-radius: var(--card-border-radius);
  padding: 40px 30px;
  border: 1px solid var(--border-color);
  transition: transform var(--transition-speed) ease, box-shadow var(--transition-speed) ease;
  display: flex;
  flex-direction: column;
  position: relative;
}

.pricing-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.pricing-card.popular {
  border-color: var(--accent-color);
  box-shadow: 0 0 30px rgba(99, 102, 241, 0.2);
}

.badge {
  position: absolute;
  top: -12px;
  right: 20px;
  background: linear-gradient(90deg, #f59e0b, #ef4444);
  color: white;
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: bold;
}

.plan-name {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 15px;
  color: var(--text-secondary);
}

.plan-price {
  font-size: 42px;
  font-weight: 800;
  margin-bottom: 30px;
  color: var(--text-primary);
}

.plan-price span {
  font-size: 16px;
  font-weight: normal;
  color: var(--text-secondary);
}

.plan-features {
  list-style: none;
  margin-bottom: 40px;
  flex-grow: 1;
}

.plan-features li {
  margin-bottom: 15px;
  display: flex;
  align-items: flex-start;
  font-size: 14px;
  color: #d1d5db;
}

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

.btn-buy {
  background-color: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: #fff;
  width: 100%;
}

.btn-buy:hover {
  background-color: rgba(255, 255, 255, 0.1);
}

.popular .btn-buy {
  background-color: var(--accent-color);
  border-color: var(--accent-color);
}

.popular .btn-buy:hover {
  background-color: var(--accent-hover);
}

/* Reviews */
.reviews {
  padding: 60px 0;
  background-color: rgba(26, 34, 53, 0.5);
}

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

.review-card {
  background-color: var(--surface-color);
  padding: 30px;
  border-radius: var(--card-border-radius);
  border: 1px solid var(--border-color);
}

.stars {
  color: var(--highlight-color);
  margin-bottom: 15px;
}

.review-text {
  font-style: italic;
  margin-bottom: 20px;
  color: #e5e7eb;
}

.reviewer {
  display: flex;
  align-items: center;
}

.avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: #374151;
  margin-right: 15px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
}

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

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

.faq-item {
  background-color: var(--surface-color);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  margin-bottom: 15px;
  overflow: hidden;
}

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

.faq-icon {
  transition: transform 0.3s ease;
}

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

.faq-answer {
  padding: 0 20px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  color: var(--text-secondary);
}

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

/* Articles Section */
.articles-nav {
  padding: 60px 0;
  border-top: 1px solid var(--border-color);
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

.article-link-card {
  display: block;
  padding: 20px;
  background-color: var(--surface-color);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  transition: all 0.2s ease;
}

.article-link-card:hover {
  border-color: var(--accent-color);
  transform: translateY(-2px);
  background-color: var(--surface-hover);
}

.article-link-card h3 {
  font-size: 16px;
  color: var(--text-primary);
  margin-bottom: 10px;
}

.article-link-card p {
  font-size: 13px;
  color: var(--text-secondary);
}

/* Article Page specific */
.article-content {
  max-width: 800px;
  margin: 40px auto;
  background-color: var(--surface-color);
  padding: 50px;
  border-radius: var(--card-border-radius);
  border: 1px solid var(--border-color);
}

.article-content h1 {
  font-size: 36px;
  margin-bottom: 20px;
  color: var(--text-primary);
}

.article-content h2 {
  font-size: 24px;
  margin: 30px 0 15px;
  color: #e5e7eb;
}

.article-content p {
  margin-bottom: 20px;
  color: #d1d5db;
  font-size: 16px;
  line-height: 1.8;
}

.article-content ul, .article-content ol {
  margin-bottom: 20px;
  padding-left: 20px;
  color: #d1d5db;
}

.article-content li {
  margin-bottom: 10px;
}

/* Footer */
footer {
  text-align: center;
  padding: 40px 0;
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 14px;
}

@media (max-width: 768px) {
  .hero h1 {
    font-size: 32px;
  }
  .article-content {
    padding: 30px 20px;
  }
}