/* Sticky Navigation Bar - Glassmorphic */
.main-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: var(--glass-bg);
  backdrop-filter: blur(20px) saturate(1.2);
  -webkit-backdrop-filter: blur(20px) saturate(1.2);
  border-bottom: 1px solid var(--glass-border);
  z-index: 9999;
  padding: 0.85rem 2rem;
  transition: all var(--transition-normal);
  opacity: 0;
  transform: translateY(-100%);
}

.main-nav.visible {
  opacity: 1;
  transform: translateY(0);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  letter-spacing: 0.05em;
}

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--white);
  text-decoration: none;
  opacity: 0.7;
  transition: all var(--transition-normal);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  position: relative;
}

.nav-links a:hover {
  opacity: 1;
  color: var(--primary);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--primary), var(--primary-soft));
  transition: width var(--transition-normal);
  border-radius: 1px;
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.nav-links a.active {
  opacity: 1;
  color: var(--primary);
}

.nav-cta-btn {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.6rem 1.4rem;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-soft) 100%);
  color: #0a0e14;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: all var(--transition-normal);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  box-shadow: 0 2px 12px var(--primary-glow);
}

.nav-cta-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px var(--primary-glow);
  background: linear-gradient(135deg, #5aa5ff 0%, var(--primary) 100%);
}

/* Mobile menu toggle */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--white);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.5rem;
}

/* Back to Top Button */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 48px;
  height: 48px;
  background: var(--glass-bg-solid);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: 14px;
  color: var(--primary);
  font-size: 1.4rem;
  cursor: pointer;
  opacity: 0;
  transform: translateY(100px);
  transition: all var(--transition-slow);
  z-index: 9998;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
}

.back-to-top.visible {
  opacity: 1;
  transform: translateY(0);
}

.back-to-top:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.4), 0 0 20px var(--primary-glow);
  border-color: var(--glass-border-hover);
  background: var(--glass-bg);
}

.back-to-top:active {
  transform: translateY(-2px);
}

/* Responsive */
@media (max-width: 768px) {
  .main-nav {
    padding: 0.75rem 1rem;
  }

  .nav-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--glass-bg-solid);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    flex-direction: column;
    gap: 0;
    padding: 1rem;
    border-bottom: 1px solid var(--glass-border);
    opacity: 0;
    transform: translateY(-20px);
    pointer-events: none;
    transition: all var(--transition-normal);
  }

  .nav-links.active {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
  }

  .nav-links li {
    padding: 0.75rem 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  }

  .nav-links li:last-child {
    border-bottom: none;
  }

  .nav-cta-btn {
    width: 100%;
    margin-top: 0.5rem;
    padding: 0.75rem 1.5rem;
  }

  .back-to-top {
    bottom: 1.5rem;
    right: 1.5rem;
    width: 44px;
    height: 44px;
    font-size: 1.3rem;
  }
}

@media (max-width: 480px) {
  .back-to-top {
    bottom: 1rem;
    right: 1rem;
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
  }
}