<header>
  <nav>
    <h1 class="logo">LOGO</h1>
    
    <ul class="menu">
      <li><a href="">About</a></li>
      <li><a href="">Projects</a></li>
      <li><a href="">Contact</a></li>
    </ul>

    <ul class="social">
      <li><a href="">Facebook</a></li>
      <li><a href="">Twitter</a></li>
    </ul>
  </nav>
</header>

body {
  font: normal 16px/1.5 "Helvetica Neue", sans-serif;
}

body, a {
  color: #fff;
}

nav {
  background: #333;
  display: flex;
  flex-direction: column;
  height: 100vh;
  width: 180px;
  padding: 20px;
  box-sizing: border-box;
}

ul {
  margin: 0;
  padding: 0;
}

li {
  list-style-type: none;
}

li a {
  display: block;
  text-decoration: none;
  padding: 10px 5px;
}

li:not(:last-child) a {
  margin-bottom: 5px; 
}

.menu {
  margin-top: 60px;
  margin-bottom: auto;
  
/**
  * Second method: 
  * - Remove: `margin-bottom: auto;`
  * - Add: `flex-grow: 1;`
  */
}