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

body {
  font-family: 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: linear-gradient(135deg, #1a1a1a 0%, #2d3748 100%);
  min-height: 100vh;
  color: #e2e8f0;
  line-height: 1.6;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 30px 20px;
}

header {
  background: rgba(45, 55, 72, 0.8);
  backdrop-filter: blur(20px);
  border-radius: 16px;
  padding: 24px 32px;
  margin-bottom: 40px;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 24px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 16px;
}

.logo h1 {
  color: #f7fafc;
  font-size: 2.2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0;
}

nav {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

nav a {
  text-decoration: none;
  color: #a0aec0;
  padding: 12px 20px;
  border-radius: 12px;
  background: rgba(45, 55, 72, 0.6);
  border: 1px solid rgba(66, 153, 225, 0.2);
  transition: all 0.2s ease;
  font-weight: 500;
  font-size: 0.95rem;
  letter-spacing: -0.01em;
}

.menu_b:hover {
  background: #4299e1;
  color: white;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(66, 153, 225, 0.4);
  border-color: #4299e1;
}

.menu_l:hover {
  background: #42e172;
  color: white;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(69, 225, 66, 0.4);
  border-color: #42e162;
}

.menu_lg:hover {
  background: #e14242;
  color: white;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(225, 66, 66, 0.4);
  border-color: #e14242;
}

.menu_s:hover {
    background: #4299e1;
    color: white;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(66, 153, 225, 0.4);
    border-color: #4589ff;
}

main {
  background: rgba(45, 55, 72, 0.8);
  backdrop-filter: blur(20px);
  border-radius: 16px;
  padding: 48px 40px;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.welcome-section {
  text-align: center;
  margin-bottom: 48px;
}

.welcome-section h2 {
  font-size: 2rem;
  margin-bottom: 16px;
  color: #f7fafc;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.welcome-section p {
  font-size: 1.1rem;
  color: #cbd5e0;
  line-height: 1.7;
  max-width: 600px;
  margin: 0 auto 32px;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
  margin-top: 40px;
}

.feature-card {
  background: rgba(26, 32, 44, 0.6);
  border-radius: 12px;
  padding: 32px 24px;
  transition: all 0.2s ease;
  border: 1px solid rgba(66, 153, 225, 0.2);
  text-align: center;
}

.feature-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(66, 153, 225, 0.2);
  background: rgba(26, 32, 44, 0.8);
  border-color: rgba(66, 153, 225, 0.4);
}

.feature-icon {
  font-size: 2.2rem;
  margin-bottom: 20px;
  display: block;
  opacity: 0.9;
}

.feature-card h3 {
  color: #f7fafc;
  margin-bottom: 12px;
  font-size: 1.2rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.feature-card p {
  color: #cbd5e0;
  font-size: 0.95rem;
  line-height: 1.6;
}

/* 스크롤바 스타일링 */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: rgba(26, 32, 44, 0.3);
}

::-webkit-scrollbar-thumb {
  background: rgba(66, 153, 225, 0.5);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: rgba(66, 153, 225, 0.7);
}

/* 반응형 디자인 */
@media (max-width: 768px) {
  .container {
    padding: 20px 16px;
  }

  header {
    padding: 20px 24px;
  }

  .header-content {
    flex-direction: column;
    text-align: center;
    gap: 20px;
  }

  .logo h1 {
    font-size: 1.8rem;
  }

  nav {
    justify-content: center;
  }

  nav a {
    padding: 10px 16px;
    font-size: 0.9rem;
  }

  main {
    padding: 32px 24px;
  }

  .welcome-section h2 {
    font-size: 1.7rem;
  }

  .welcome-section p {
    font-size: 1rem;
  }

  .stats {
    gap: 24px;
  }

  .stat-number {
    font-size: 1.8rem;
  }

  .features-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .feature-card {
    padding: 24px 20px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 16px 12px;
  }

  header {
    padding: 16px 20px;
  }

  .logo h1 {
    font-size: 1.6rem;
  }

  main {
    padding: 24px 20px;
  }

  .welcome-section h2 {
    font-size: 1.5rem;
  }
}