Navbars

<nav class="navbar">
  <span class="logo">Brand</span>
  <ul class="nav-links">
    <li><a href="#">Home</a></li>
    <li><a href="#">Docs</a></li>
    <li><a href="#">Blog</a></li>
  </ul>
  <button class="cta">Sign Up</button>
</nav>

.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  background: rgba(13,15,20,0.88);
  border-bottom: 1px solid rgba(255,255,255,0.08);
  padding: 0 2rem;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}
.nav-links a {
  font-size: 0.82rem;
  color: #9aa0b8;
  text-decoration: none;
  transition: color 0.18s;
}
.nav-links a:hover { color: #e4e8f0; }
.cta {
  background: #5af0c4;
  color: #0d0f14;
  border: none;
  padding: 0.45rem 1.1rem;
  border-radius: 6px;
  font-weight: 700;
  cursor: pointer;
}

<nav class="navbar">
  <span class="logo">Acme</span>
  <ul class="nav-links">
    <li><a href="#" class="active">Home</a></li>
    <li><a href="#">Products</a></li>
    <li><a href="#">About</a></li>
    <li><a href="#">Contact</a></li>
  </ul>
</nav>

.nav-links a {
  position: relative;
  color: #9aa0b8;
  text-decoration: none;
  padding: 0.35rem 0.75rem;
  transition: color 0.2s;
}
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0.75rem; right: 0.75rem;
  height: 2px;
  background: #7b8cff;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s ease;
}
.nav-links a:hover,
.nav-links a.active { color: #e4e8f0; }
.nav-links a:hover::after,
.nav-links a.active::after {
  transform: scaleX(1);
}

<nav class="navbar" id="mainNav">
  <span class="logo">Studio</span>
  <ul class="nav-links">
    <li><a href="#">Work</a></li>
    <li><a href="#">Services</a></li>
  </ul>
</nav>

<script>
const nav = document.getElementById('mainNav');
window.addEventListener('scroll', () => {
  nav.classList.toggle('scrolled', scrollY > 0);
});
</script>

.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  background: transparent;
  border-bottom: 1px solid transparent;
  transition: background 0.35s, border-color 0.35s;
  height: 60px;
  display: flex;
  align-items: center;
  padding: 0 2rem;
}
.navbar.scrolled {
  background: rgba(13,15,20,0.95);
  backdrop-filter: blur(12px);
  border-bottom-color: #2a2f42;
}

<nav class="navbar">
  <span class="logo">Startup</span>
  <button class="hamburger" id="hb">
    <span></span><span></span><span></span>
  </button>
</nav>
<div class="mobile-menu" id="menu">
  <a href="#">Home</a>
  <a href="#">Features</a>
  <a href="#">Pricing</a>
</div>
<script>
hb.addEventListener('click', () => {
  hb.classList.toggle('open');
  menu.classList.toggle('open');
});
</script>

.hamburger {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
}
.hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: #9aa0b8;
  transition: transform 0.3s, opacity 0.3s;
}
.hamburger.open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}
.mobile-menu {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease;
}
.mobile-menu.open { max-height: 300px; }