html {
  scroll-behavior: smooth;
}

.top-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(11,18,32,0.85);
  backdrop-filter: blur(8px);
  padding: 12px 20px;
  display: flex;
  justify-content: center;
  gap: 24px;
  z-index: 9999;
}

:root.light .top-nav {
  background: rgba(244,247,251,0.85);
}

.top-nav a {
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  transition: color 0.25s ease;
}

.top-nav a:hover {
  color: var(--accent);
}

.top-nav a.active {
  color: var(--accent);
}

.top-nav a::after {
  display: none;
}

#scrollTopBtn {
  position: fixed;
  bottom: 30px;
  right: 30px;
  background: var(--accent);
  color: var(--bg);
  padding: 12px 14px;
  border-radius: 50%;
  font-size: 1.4rem;
  cursor: pointer;
  display: none;
  box-shadow: 0 8px 20px rgba(0,0,0,0.3);
  transition: opacity 0.3s ease;
}