body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  line-height: 1.5;
  background: #ffffff;
}

.top-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: #ffffff;
  border-bottom: 1px solid #ddd;
  overflow-x: auto;
  white-space: nowrap;
  scrollbar-width: none;
}

.top-nav::-webkit-scrollbar {
  display: none;
}

.nav-list {
  display: inline-flex;
  gap: 1rem;
  padding: 0.7rem 1rem;
}

.nav-link {
  color: #999999;
  border-bottom: 1px dashed #999999;
  text-decoration: none;
  font-size: 0.9rem;
  transition: all 0.2s ease;
  cursor: pointer;
}

.nav-link:hover {
  color: #555;
}

.nav-link.active {
  color: #f94125;
  border-bottom: none;
  font-weight: 700;
  font-size: 1rem;
  text-decoration: none;
}

.content {
  max-width: 900px;
  margin: 0 auto;
  padding: 1rem 1rem 3rem;
}

.article-block {
  background: #ffffff;
  margin-top: 1.1rem;
  padding: 1rem;
  border-bottom: 1px solid #eee;
}

.article-title {
  margin: 0 0 0.45rem;
  font-size: 1.05rem;
}

.article-meta {
  font-size: 0.7rem;
  color: #777;
  margin-bottom: 0.5rem;
}

@media (max-width: 600px) {
  .nav-list {
    gap: 0.8rem;
    padding: 0.6rem 0.7rem;
  }
  .nav-link {
    font-size: 0.85rem;
  }
  .nav-link.active {
    font-size: 0.95rem;
  }
}