CSS Only Off-canvas Menu with Shrinking Main Content

Yet another pure CSS off-canvas menu concept that reveals an 0ff-screen navigation menu while shrinking the main content as you seen on the demo page.

How to use it:

Build the html markup for the off-canvas menu with a toggle button using checkbox & label tricks.

<div class="container">
  <input type="checkbox" id="new" style="display:none;">
  <h1>OffCanvas Menu</h1>
  <nav>
    <ul>
      <li><a href="#">Home</a></li>
      <li><a href="#">About</a></li>
      <li><a href="#">Contact</a></li>
      <li><a href="#">Blog</a></li>
      <li><a href="#">Social</a></li>
    </ul>
  </nav>
  <main>
    <label class="toggleMenu" for="new">
      <span class="bar"></span> 
      <span class="bar"></span> 
      <span class="bar"></span> 
    </label>
    Main Content Goes Here
  </main>
</div>

The main CSS styles for the off-canvas menu.

nav { width: 30%; }
nav ul {
  list-style-type: none;
  padding: 0;
  width: 70%;
  margin: 100px auto 0;
}
nav ul li {
  font-size: 1.7em;
  transform: translateX(-30px);
  -webkit-transform: translateX(-30px);
  -moz-transform: translateX(-30px);
  -o-transform: translateX(-30px);
  -ms-transform: translateX(-30px);
  opacity: 0;
}
nav ul li:nth-child(1) {
  transition: all 0.3s ease-out 0.2s;
  -webkit-transition: all 0.3s ease-out 0.2s;
  -moz-transition: all 0.3s ease-out 0.2s;
  -o-transition: all 0.3s ease-out 0.2s;
  -ms-transition: all 0.3s ease-out 0.2s;
}
nav ul li:nth-child(2) {
  transition: all 0.3s ease-out 0.4s;
  -webkit-transition: all 0.3s ease-out 0.4s;
  -moz-transition: all 0.3s ease-out 0.4s;
  -o-transition: all 0.3s ease-out 0.4s;
  -ms-transition: all 0.3s ease-out 0.4s;
}
nav ul li:nth-child(3) {
  transition: all 0.3s ease-out 0.6s;
  -webkit-transition: all 0.3s ease-out 0.6s;
  -moz-transition: all 0.3s ease-out 0.6s;
  -o-transition: all 0.3s ease-out 0.6s;
  -ms-transition: all 0.3s ease-out 0.6s;
}
nav ul li:nth-child(4) {
  transition: all 0.3s ease-out 0.8s;
  -webkit-transition: all 0.3s ease-out 0.8s;
  -moz-transition: all 0.3s ease-out 0.8s;
  -o-transition: all 0.3s ease-out 0.8s;
  -ms-transition: all 0.3s ease-out 0.8s;
}
nav ul li:nth-child(5) {
  transition: all 0.3s ease-out 1s;
  -webkit-transition: all 0.3s ease-out 1s;
  -moz-transition: all 0.3s ease-out 1s;
  -o-transition: all 0.3s ease-out 1s;
  -ms-transition: all 0.3s ease-out 1s;
}
nav ul li a {
  text-decoration: none;
  display: block;
  padding: 10px 0;
  text-align: center;
  margin-top: 5px;
  color: #fff;
  position: relative;
}
nav ul li a::before, nav ul li a::after {
  content: " ";
  height: 100%;
  position: absolute;
  top: 0;
  background-color: #03A9F4;
  width: 0;
  transition: all 0.3s ease-in-out;
  -webkit-transition: all 0.3s ease-in-out;
  -moz-transition: all 0.3s ease-in-out;
  -o-transition: all 0.3s ease-in-out;
  -ms-transition: all 0.3s ease-in-out;
}
nav ul li a::before { left: 0; }
nav ul li a::after { right: 0; }
nav ul li a:hover {
  color: #03A9F4;
  text-decoration: none;
  text-shadow: 0 0 2px #03A9F4;
}
nav ul li a:hover::before, nav ul li a:hover::after {
  width: 5px;
  box-shadow: 0 0 5px 1px #03A9F4;
  -webkit-box-shadow: 0 0 5px 1px #03A9F4;
  -moz-box-shadow: 0 0 5px 1px #03A9F4;
  -o-box-shadow: 0 0 5px 1px #03A9F4;
  -ms-box-shadow: 0 0 5px 1px #03A9F4;
}

The required CSS rules for the menu toggle button.

input:checked ~ main {
  height: 100%;
  box-shadow: 0 0 100px 10px rgba(0, 0, 0, 0.7);
  -webkit-box-shadow: 0 0 100px 10px rgba(0, 0, 0, 0.7);
  -moz-box-shadow: 0 0 100px 10px rgba(0, 0, 0, 0.7);
  -o-box-shadow: 0 0 100px 10px rgba(0, 0, 0, 0.7);
  -ms-box-shadow: 0 0 100px 10px rgba(0, 0, 0, 0.7);
  transform: scale(0.6);
  -webkit-transform: scale(0.6);
  -moz-transform: scale(0.6);
  -o-transform: scale(0.6);
  -ms-transform: scale(0.6);
  right: -12%;
  cursor: pointer;
  overflow: hidden;
}
input:checked ~ main h1 { margin-top: 75.5px; }
input:checked ~ main .toggleMenu {
  position: absolute;
  width: 100%;
  top: 0;
  left: 0;
  height: 100%;
  z-index: 10;
}
input:checked ~ nav ul li {
  transform: translateX(0);
  -webkit-transform: translateX(0);
  -moz-transform: translateX(0);
  -o-transform: translateX(0);
  -ms-transform: translateX(0);
  opacity: 1;
}
input:checked ~ nav ul li:nth-child(1) {
  transition: all 0.3s linear 0;
  -webkit-transition: all 0.3s linear 0;
  -moz-transition: all 0.3s linear 0;
  -o-transition: all 0.3s linear 0;
  -ms-transition: all 0.3s linear 0;
}
input:checked ~ nav ul li:nth-child(2) {
  transition: all 0.3s linear 0;
  -webkit-transition: all 0.3s linear 0;
  -moz-transition: all 0.3s linear 0;
  -o-transition: all 0.3s linear 0;
  -ms-transition: all 0.3s linear 0;
}
input:checked ~ nav ul li:nth-child(3) {
  transition: all 0.3s linear 0;
  -webkit-transition: all 0.3s linear 0;
  -moz-transition: all 0.3s linear 0;
  -o-transition: all 0.3s linear 0;
  -ms-transition: all 0.3s linear 0;
}
input:checked ~ nav ul li:nth-child(4) {
  transition: all 0.3s linear 0;
  -webkit-transition: all 0.3s linear 0;
  -moz-transition: all 0.3s linear 0;
  -o-transition: all 0.3s linear 0;
  -ms-transition: all 0.3s linear 0;
}
input:checked ~ nav ul li:nth-child(5) {
  transition: all 0.3s linear 0;
  -webkit-transition: all 0.3s linear 0;
  -moz-transition: all 0.3s linear 0;
  -o-transition: all 0.3s linear 0;
  -ms-transition: all 0.3s linear 0;
}
main .toggleMenu {
  background-color: transparent;
  cursor: pointer;
  padding: 10px;
  display: block;
  width: 30px;
}
main .toggleMenu span.bar {
  display: block;
  width: 28px;
  height: 5px;
  margin: 4px 1px;
  background-color: #888;
}

The required CSS styles for the main container.

.container {
  position: fixed;
  width: 100%;
  height: 100%;
  background-color: #222;
}
.container main {
  border: 1px solid #ddd;
  height: 100%;
  width: 100%;
  position: fixed;
  top: 0;
  right: 0;
  background-color: #fff;
  overflow-x: hidden;
  overflow-y: scroll;
  transition: all 0.5s ease-in-out;
  -webkit-transition: all 0.5s ease-in-out;
  -moz-transition: all 0.5s ease-in-out;
  -o-transition: all 0.5s ease-in-out;
  -ms-transition: all 0.5s ease-in-out;
}
}