<div class="page">
  <header tabindex="0">Header</header>
  <div id="nav-container">
    <div class="bg"></div>
    <div class="button" tabindex="0">
      <span class="icon-bar"></span>
      <span class="icon-bar"></span>
      <span class="icon-bar"></span>
    </div>
    <div id="nav-content" tabindex="0">
      <ul>
        <li><a href="#0">Home</a></li>
        <li><a href="#0">Services</a></li>
        <li><a href="#0">Blog</a></li>
        <li><a href="#0">About</a></li>
        <li><a href="#0">Contact</a></li>
        <li class="small"><a href="#0">Facebook</a><a href="#0">Instagram</a></li>
      </ul>
    </div>
  </div>

  <main>
    <div class="content">
      <h2>Off-screen navigation using <span>:focus-within</span></h2>
      <p>Adding yet another pure CSS technique to the list of off-screen navigation by "hacking" the :focus-within pseudo-class. Have a look at the code to see how it works.</p>
      <small><strong>NB!</strong> Use a browser that supports :focus-within</small>
    </div>
  </main>
</div>

@import url('https://fonts.googleapis.com/css?family=Encode+Sans+Condensed:400,600');

* {
  outline: none;
}

strong {
  font-weight: 600;
}

.page {
  width: 100%;
  height: 100vh;
  background: #fdfdfd;
  font-family: 'Encode Sans Condensed', sans-serif;
  font-weight: 600;
  letter-spacing: .03em;
  color: #212121;
}

header {
  display: flex;
  position: fixed;
  width: 100%;
  height: 70px;
  background: #212121;
  color: #fff;
  justify-content: center;
  align-items: center;
  -webkit-tap-highlight-color: rgba(0,0,0,0);
}

main {
  padding: 70px 20px 0;
  display: flex;
  flex-direction: column;
  height: 100%;
}

main > div {
  margin: auto;
  max-width: 600px;
}

main h2 span {
  color: #BF7497;
}

main p {
  line-height: 1.5;
  font-weight: 200;
  margin: 20px 0;
}

main small {
  font-weight: 300;
  color: #888;
}

#nav-container {
  position: fixed;
  height: 100vh;
  width: 100%;
  pointer-events: none;
}
#nav-container .bg {
  position: absolute;
  top: 70px;
  left: 0;
  width: 100%;
  height: calc(100% - 70px);
  visibility: hidden;
  opacity: 0;
  transition: .3s;
  background: #000;
}
#nav-container:focus-within .bg {
  visibility: visible;
  opacity: .6;
}
#nav-container * {
  visibility: visible;
}

.button {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
  z-index: 1;
  -webkit-appearance: none;
  border: 0;
  background: transparent;
  border-radius: 0;
  height: 70px;
  width: 30px;
  cursor: pointer;
  pointer-events: auto;
  margin-left: 25px;
  touch-action: manipulation;
  -webkit-tap-highlight-color: rgba(0,0,0,0);
}
.icon-bar {
  display: block;
  width: 100%;
  height: 3px;
  background: #aaa;
  transition: .3s;
}
.icon-bar + .icon-bar {
  margin-top: 5px;
}

#nav-container:focus-within .button {
  pointer-events: none;
}
#nav-container:focus-within .icon-bar:nth-of-type(1) {
  transform: translate3d(0,8px,0) rotate(45deg);
}
#nav-container:focus-within .icon-bar:nth-of-type(2) {
  opacity: 0;
}
#nav-container:focus-within .icon-bar:nth-of-type(3) {
  transform: translate3d(0,-8px,0) rotate(-45deg);
}

#nav-content {
  margin-top: 70px;
  padding: 20px;
  width: 90%;
  max-width: 300px;
  position: absolute;
  top: 0;
  left: 0;
  height: calc(100% - 70px);
  background: #ececec;
  pointer-events: auto;
  -webkit-tap-highlight-color: rgba(0,0,0,0);
  transform: translateX(-100%);
  transition: transform .3s;
  will-change: transform;
  contain: paint;
}

#nav-content ul {
  height: 100%;
  display: flex;
  flex-direction: column;
}

#nav-content li a {
  padding: 10px 5px;
  display: block;
  text-transform: uppercase;
  transition: color .1s;
}

#nav-content li a:hover {
  color: #BF7497;
}

#nav-content li:not(.small) + .small {
  margin-top: auto;
}

.small {
  display: flex;
  align-self: center;
}

.small a {
  font-size: 12px;
  font-weight: 400;
  color: #888;
}
.small a + a {
  margin-left: 15px;
}

#nav-container:focus-within #nav-content {
  transform: none;
}






* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  height: 100%;
}

a,
a:visited,
a:focus,
a:active,
a:link {
  text-decoration: none;
  outline: 0;
}

a {
  color: currentColor;
  transition: .2s ease-in-out;
}

h1, h2, h3, h4 {
  margin: 0;
}

ul {
  padding: 0;
  list-style: none;
}

img {
  vertical-align: middle;
  height: auto;
  width: 100%;
}

/* Don't use this technique in production! */

// No JS :)