Off-canvas Sidebar Push Navigation In Pure CSS/CSS3

A mobile-first, off-canvas sidebar navigation (push menu) system written in pure CSS/CSS3 and checkbox tricks.

How to use it:

Code the HTML for the side navigation.

<aside id="sidebar">
  <header class="navbar-header">
      <a href="#" class="brand-logo"> Brand Logo </a>
  </header>
  <main class="navbar-body">
    <ul>
      <li class="nav-item">
        <a href="" class="nav-link"> Menu Item 1 </a>
      </li>
      <li class="nav-item">
        <a href="" class="nav-link"> Menu Item 2 </a>
      </li>
      <li class="nav-item">
        <a href="" class="nav-link"> Menu Item 3 </a>
      </li>
      ...
    </ul>
  </main>
</aside>

Create a checkbox input to toggle the side navigation.

<input type="checkbox" name="checkbox" id="checkbox">

Create a menu toggle button inside the main content.

<main id="main-content">
  <label for="checkbox" class="check-box">
    <span class="line line1"></span>
    <span class="line line3"></span>
    <span class="line line2"></span>
  </label>
  <h1>Main Content Here</h1>
</main>

The primary CSS for the side navigation.

#sidebar {
  padding: 20px 0;
  background-color: #3F51B5;
  width: 220px;
  visibility: visible;
  opacity: 1;
  -webkit-transform: translateX(0);
          transform: translateX(0);
  -webkit-transition: 250ms ease-in;
  transition: 250ms ease-in;
  -webkit-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
          box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
}
#sidebar .navbar-header {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  padding: 10px 20px;
}
#sidebar .navbar-header .brand-logo {
  font-size: 1.5em;
  -webkit-transform: translateX(0);
          transform: translateX(0);
  -webkit-transition: 250ms ease-in;
  transition: 250ms ease-in;
  visibility: visible;
}
.navbar-body .nav-item {
  padding: 10px 20px;
  cursor: pointer;
  -webkit-transition: 400ms all ease-in-out;
  transition: 400ms all ease-in-out;
  -webkit-transform: translateX(0);
          transform: translateX(0);
}
.navbar-body .nav-item:hover {
  background-color: #7280ce;
}

Toggle the side navigation using checkbox and label tricks.

#checkbox {
  display: none;
}
#checkbox:checked ~ #sidebar {
  width: 0;
  -webkit-animation: sidebarAnim 500ms;
          animation: sidebarAnim 500ms;
}
#checkbox:checked ~ #sidebar .nav-item {
  -webkit-transform: translateX(-200px);
          transform: translateX(-200px);
}
#checkbox:checked ~ #sidebar .brand-logo {
  -webkit-transform: translateX(-200px);
          transform: translateX(-200px);
  visibility: hidden;
}
#checkbox:checked ~ #sidebar .navbar-header {
  visibility: hidden;
}

Style the menu toggle button.

#main-content .check-box {
  cursor: pointer;
  display: inline-block;
}
#main-content .check-box .line {
  width: 20px;
  height: 2px;
  background-color: #212121;
  margin: 4px 0;
  display: block;
}

The CSS animations for the side navigation.

@-webkit-keyframes sidebarAnim {
  0% {
    width: 220px;
    opacity: 1;
    -webkit-transform: translateX(0);
            transform: translateX(0);
    visibility: visible;
  }
  50% {
    width: 220px;
  }
  100% {
    width: 0;
    opacity: 0;
    -webkit-transform: translateX(-220px);
            transform: translateX(-220px);
    visibility: hidden;
  }
}
@keyframes sidebarAnim {
  0% {
    width: 220px;
    opacity: 1;
    -webkit-transform: translateX(0);
            transform: translateX(0);
    visibility: visible;
  }
  50% {
    width: 220px;
  }
  100% {
    width: 0;
    opacity: 0;
    -webkit-transform: translateX(-220px);
            transform: translateX(-220px);
    visibility: hidden;
  }
}