<ul class="sidebar">
  <li>Home</li>
  <li>Products</li>
  <li>Details</li>
  <li>Where to buy</li>
  <li>Contact</li>
  <li>About</li>
</ul>

<input type="checkbox" id="sidebar-btn" class="sidebar-btn" checked/>
<label for="sidebar-btn"></label>

<div class="content">
  <h1>Flat CSS Sidebar</h1>
</div>

@import "compass";
@import url(https://fonts.googleapis.com/css?family=Ubuntu:400,500,700,300);
@import url(https://fonts.googleapis.com/css?family=Lobster);

$side-menu-btn-color: #c0392b;

*, *:before, *:after {
  padding:0;
  margin:0;
}

body {
  overflow-x: hidden;
  color: #fff;
  font-family: "HelveticaNeue-Light", "Helvetica Neue Light", "Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif; 
  font-weight: 300;
}

body, html {
  width:100%;
  height:100%;
}

h1 {
  font-family: 'Lobster', cursive;
  font-weight:300;
  font-size: 2.5em;
}

.sidebar-btn {
  position: absolute;
  clip: rect(0, 0, 0, 0);
}

label[for="sidebar-btn"] {
  position: fixed;
  left: 15px; 
  top: 15px;
  z-index: 2;
  height: 30px;
  width: 30px;
  cursor: pointer;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' version='1.1' x='0px' y='0px' width='30px' height='30px' viewBox='0 0 30 30' enable-background='new 0 0 30 30' xml:space='preserve'><rect style='fill:rgb(255,255,255)' width='15' height='3'/><rect style='fill:rgb(255,255,255)' y='8' width='20' height='3'/><rect style='fill:rgb(255,255,255)' y='16' width='25' height='3'/></svg>");
  background-size: contain;
}

.sidebar-btn + label, .content {
  transition: left 0.1s;
}

.sidebar-btn:checked + label {
  left: 245px;
}

.sidebar-btn:checked ~ .content {
  left: 230px;
}

.sidebar {
  list-style-type: none;
  width: 100%;
  height: 100%;
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 0;
  background-color: $side-menu-btn-color;
}

.sidebar li {
  background-color: $side-menu-btn-color;
  padding:1em;
  color: #fff;
  width:300px;
  font-family: 'Ubuntu', sans-serif;
  font-weight:400;  
  @include transition-property(all);
  @include transition-duration(50ms);
  @include transition-timing-function(ease-in);

  &:hover {
    background-color: darken($side-menu-btn-color, 10);
  }
}

.content {
  min-height: 100%;
  min-width: 100%;
  background-color: #34495e;
  position: relative;
  top: 0;
  bottom: 100%;
  left: 0;
  z-index: 1;  
  padding: 4em;
}