:root {
  --bg-color: #0a0a0f;
  --text-primary: #f0f0f5;
  --text-secondary: #7a8599;
  --accent-color: #3b82f6;
  --accent-glow: rgba(59, 130, 246, 0.4);
  --card-bg: rgba(255, 255, 255, 0.02);
  --card-border: rgba(255, 255, 255, 0.06);
  --font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", system-ui, sans-serif;
}

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

body {
  background-color: var(--bg-color);
  color: var(--text-primary);
  font-family: var(--font-family);
  line-height: 1.5;
  font-size: 14px;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: -0.02em;
}

a {
  text-decoration: none;
  color: inherit;
  transition: color 0.2s;
}

.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* Header - Compact */
header {
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 100;
  padding: 0.75rem 0;
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--card-border);
}

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

.logo {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.03em;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 500;
  transition: color 0.2s;
}

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

/* Hero - Compact */
.hero {
  min-height: 50vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 6rem 0 3rem;
  position: relative;
}

.hero::before {
  content: '';
  position: absolute;
  top: 40%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  opacity: 0.2;
  z-index: -1;
  filter: blur(60px);
}

.hero-title {
  font-size: 2.5rem;
  margin-bottom: 0.75rem;
  font-weight: 700;
}

.hero-title span {
  background: linear-gradient(135deg, var(--accent-color), #60a5fa);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 0.95rem;
  color: var(--text-secondary);
  max-width: 480px;
  margin: 0 auto 1.5rem;
  line-height: 1.6;
}

.btn {
  display: inline-block;
  padding: 0.6rem 1.5rem;
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 500;
  background: var(--accent-color);
  color: white;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
}

.btn:hover {
  background: #2563eb;
  transform: translateY(-1px);
}

/* Sections */
.content-section {
  padding: 3rem 0;
}

.section-title {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  text-align: center;
  font-weight: 600;
}

/* Card Grid - Compact */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 1.25rem;
  transition: all 0.2s;
  cursor: pointer;
}

.card:hover {
  border-color: rgba(59, 130, 246, 0.3);
  background: rgba(255, 255, 255, 0.03);
}

.card-icon {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: rgba(59, 130, 246, 0.1);
  border-radius: 8px;
}

.card h3 {
  font-size: 1rem;
  margin-bottom: 0.5rem;
  font-weight: 600;
}

.card p {
  color: var(--text-secondary);
  font-size: 0.8rem;
  line-height: 1.5;
}

/* Article List - Compact */
.article-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  max-width: 700px;
  margin: 0 auto;
}

.article-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: all 0.2s;
}

.article-card:hover {
  background: rgba(255, 255, 255, 0.03);
  border-color: rgba(59, 130, 246, 0.3);
}

.article-content {
  flex: 1;
  min-width: 0;
}

.article-meta {
  font-size: 0.7rem;
  color: var(--accent-color);
  margin-bottom: 0.25rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  font-weight: 500;
}

.article-title {
  font-size: 0.95rem;
  margin-bottom: 0.25rem;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.article-desc {
  color: var(--text-secondary);
  font-size: 0.8rem;
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-arrow {
  margin-left: 1rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
  flex-shrink: 0;
  transition: all 0.2s;
}

.article-card:hover .article-arrow {
  color: var(--accent-color);
  transform: translateX(2px);
}

/* Tool Grid - Compact */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 0.75rem;
}

.tool-card {
  background: var(--card-bg);
  border-radius: 8px;
  padding: 1rem;
  border: 1px solid var(--card-border);
  transition: all 0.2s;
}

.tool-card:hover {
  background: rgba(255, 255, 255, 0.03);
  border-color: rgba(59, 130, 246, 0.3);
}

.tool-header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 0.5rem;
}

.tool-icon {
  width: 28px;
  height: 28px;
  background: rgba(59, 130, 246, 0.1);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9rem;
}

.tool-card h4 {
  font-size: 0.9rem;
  font-weight: 600;
  margin: 0;
}

.tool-card p {
  color: var(--text-secondary);
  font-size: 0.75rem;
  line-height: 1.4;
}

/* Newsletter - Compact */
.newsletter-section {
  text-align: center;
  background: linear-gradient(180deg, transparent, rgba(59, 130, 246, 0.05));
  padding: 2.5rem 0 4rem;
}

.newsletter-section .hero-subtitle {
  margin-bottom: 1.25rem;
}

.newsletter-form {
  display: flex;
  gap: 0.5rem;
  max-width: 380px;
  margin: 0 auto;
}

.newsletter-input {
  flex: 1;
  padding: 0.6rem 1rem;
  border-radius: 6px;
  border: 1px solid var(--card-border);
  background: rgba(255, 255, 255, 0.05);
  color: white;
  font-family: inherit;
  font-size: 0.85rem;
  outline: none;
  transition: border-color 0.2s;
}

.newsletter-input::placeholder {
  color: var(--text-secondary);
}

.newsletter-input:focus {
  border-color: var(--accent-color);
}

/* Footer - Compact */
footer {
  padding: 1.5rem 0;
  text-align: center;
  border-top: 1px solid var(--card-border);
}

.footer-content {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer-content p {
  margin: 0;
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.beian-link {
  color: var(--text-secondary) !important;
  font-size: 0.75rem;
  opacity: 0.7;
  transition: opacity 0.2s;
}

.beian-link:hover {
  opacity: 1;
}

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.4s ease-out, transform 0.4s ease-out;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Mobile */
@media (max-width: 640px) {
  .hero-title {
    font-size: 1.75rem;
  }
  
  .hero-subtitle {
    font-size: 0.85rem;
  }
  
  .nav-links {
    display: none;
  }
  
  .card-grid {
    grid-template-columns: 1fr;
  }
  
  .newsletter-form {
    flex-direction: column;
  }
  
  .article-desc {
    display: none;
  }
  
  .footer-content {
    flex-direction: column;
    gap: 0.5rem;
  }
}