Transparent Menu Bar

<style>
/* http://foulscode.blogspot.gr */
@import url(www.foulscode.blogspot.gr);
html, body {
  height: 100%;
}
body {
  background: linear-gradient(330deg, #e05252 0%, #99e052 25%, #52e0e0 50%, #9952e0 75%, #e05252 100%);
}
nav {
  max-width: 960px;
  /* The mask-image gives us some extra fading. It is not necessary but without this, you can't face out the box-shadows. This clips our menu */
  mask-image: linear-gradient(90deg, rgba(255, 255, 255, 0) 0%, #ffffff 25%, #ffffff 75%, rgba(255, 255, 255, 0) 100%);
  margin: 0 auto;
  /* Using padding instead of margin for the top and bottom here will keep our box-shadow visible and not affected by the mask-image */
  padding: 75px 0;
}
nav ul {
  text-align: center;
  background: linear-gradient(90deg, rgba(255, 255, 255, 0) 0%, rgba(255, 255, 255, 0.2) 25%, rgba(255, 255, 255, 0.2) 75%, rgba(255, 255, 255, 0) 100%);
  width: 100%;
  box-shadow: 0 0 25px rgba(0, 0, 0, 0.1), inset 0 0 1px rgba(255, 255, 255, 0.6);
}
nav ul li {
  display: inline-block;
}
nav ul li a {
  padding: 20px;
  font-family: "Roboto";
  color: rgba(0, 0, 0, 0.5);
  text-shadow: 1px 1px 1px rgba(255, 255, 255, 0.4);
  font-size: 25px;
  text-decoration: none;
  display: block;
}
nav ul li a:hover {
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1), inset 0 0 1px rgba(255, 255, 255, 0.6);
  background: rgba(255, 255, 255, 0.1);
  color: rgba(0, 0, 0, 0.7);
}
/* http://foulscode.blogspot.gr */
</style>
<nav>
  <ul>
    <li>
      <a href="URL">Home</a>
    </li>
    <li>
      <a href="URL">Blog</a>
    </li>
    <li>
      <a href="URL">About</a>
    </li>
    <li>
      <a href="URL">Contact</a>
    </li>
  </ul>
</nav>