<nav>
  <p>Florin Pop</p>
  
  <button id="burger" class="burger">
    <div class="bar"></div>
    <div class="bar"></div>
  </button>
  
  <ul>
    <li><a href="#">Home</a></li>
    <li><a href="#">Blog</a></li>
    <li><a href="#">About</a></li>
    <li><a href="#">Contact</a></li>
  </ul>
</nav>

<header>
  <h1>This is a COOL Responsive Navigation</h1>
</header>

@import url('https://fonts.googleapis.com/css?family=Poppins&display=swap');

* {
  box-sizing: border-box;
}

body {
  background-color: #EFEFEF;
  color: #2C405E;
  font-family: 'Poppins', sans-serif;
  margin: 0;
}

header {
  background-image: url('https://images.unsplash.com/photo-1516222338250-863216ce01ea?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=2467&q=80');
  background-size: cover;
  background-position: center center;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: calc(100vh - 63px); 
  position: relative;
}

header * {
  z-index: 1;
}

header::after {
  content: '';
  background-color: #000;
  opacity: 0.4;
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 100%;
}

header h1 {
  color: #fff;
  font-size: 4em;
  text-align: center;
  width: 60%;
}

nav {
  background-color: #fff;
  box-shadow: 0 3px 5px rgba(0, 0, 0, 0.1);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  padding: 15px;
}

nav p {
  color: #0594EC;
  font-weight: bold;
  margin: 5px;
  letter-spacing: 1px;
  text-transform: uppercase;
}

.burger {
  border: 0;
  cursor: pointer;
  display: none;
  font-size: 22px;
  position: relative;
  padding: 0;
  outline: none;
  height: 30px;
  width: 30px;
}

.burger:active {
  color: #0594EC;
  outline: none;
}

.burger .bar {
  background-color: #0594EC;
  position: absolute;
  left: 50%;
  transform: translate(-50%, -50%) rotate(0deg);
  height: 3px;
  width: 20px;
  transition: transform 0.2s ease;
}

.burger .bar:first-of-type {
  top: 40%;
}

.burger .bar:last-of-type {
  top: 60%;
}

ul {
  display: flex;
  margin: 0;
  padding: 0;
  list-style-type: none;
}

ul li {
  margin: 0 10px;
}

ul li a {
  color: #2C405E;
  position: relative;
  text-decoration: none;
}

ul li a::after {
  content: '';
  background-color: #2C405E;
  position: absolute;
  bottom: -18px;
  left: 0;
  opacity: 0;
  height: 2px;
  width: 100%;
  transition: transform 0.2s ease;
}

ul li a:hover::after {
  opacity: 1;
  transform: translateY(-15px);
}

@media screen and (max-width: 480px) {
  header h1 {
    font-size: 2em;
  }
  
  .burger {
    display: block;
  }
  
  .burger.show-x .bar:first-of-type {
    transform: translate(-50%, 50%) rotate(225deg);
  }
  
  .burger.show-x .bar:last-of-type {
    transform: translate(-50%, -150%) rotate(-225deg);
  }
  
  ul {
    background-color: #fff;
    box-shadow: 0 3px 5px rgba(0, 0, 0, 0.1);
    flex-direction: column;
    text-align: center;
    position: fixed;
    top: 80px;
    left: 10%;
    transform: translateX(120%);
    width: 80%;
    transition: transform 0.3s ease-in;
    z-index: 100;
  }
  
  ul.show {
    transform: translateX(0);
  }
  
  ul li {
    margin: 15px;
  }
}

const burger = document.getElementById('burger');
const ul = document.querySelector('nav ul');

burger.addEventListener('click', () => {
  burger.classList.toggle('show-x');
  ul.classList.toggle('show');
});