Pure CSS / CSS3 Morphing Drawer Menu

Preview:

Description:

An awesome animated off-canvas drawer navigation menu with a hamburger toggle icon,  built using plain HTML and CSS / CSS3.

How to use it:

Create the off-canvas drawer menu as follows.

<menu>
  <label for="trigger">
  <input id="trigger" type="checkbox" />
  <section class="drawer-list">
    <ul>
      <li><a href="#">Home</a></li>
      <li><a href="#">Blog</a></li>
      <li><a href="#">About</a></li>
      <li><a href="#">Contact</a></li>
    </ul>
  </section>
  <hamburger> <i></i>
    <text>
      <close>close</close>
      <open>menu</open>
    </text>
  </hamburger>
  </label>
</menu>

The basic CSS styles for the off-canvas drawer menu.

menu, menu label {
  position: absolute;
  top: 0;
  right: 0;
}
menu { margin: 0; }
menu .drawer-list {
  position: fixed;
  right: 0;
  top: 0;
  height: 100vh;
  width: 100vw;
  transform: translate(100vw, 0);
  /* ie workaround */
  -ms-transform: translatex(-100vw);
  box-sizing: border-box;
  pointer-events: none;
  padding-top: 125px;
  transition: width 475ms ease-out, transform 450ms ease, border-radius .8s .1s ease;
  border-bottom-left-radius: 100vw;
  background-color: #3d81c0;
  background-color: rgba(13, 97, 176, 0.8);
}
menu .drawer-list ul {
  height: 100%;
  width: 100%;
  margin: 0;
  padding: 0;
  overflow: auto;
  overflow-x: hidden;
  pointer-events: auto;
}
menu .drawer-list li {
  list-style: none;
  text-transform: uppercase;
  pointer-events: auto;
  white-space: nowrap;
  box-sizing: border-box;
  transform: translatex(100vw);
  /* ie workaround */
  -ms-transform: translatex(-100vw);
}
menu .drawer-list li:last-child { margin-bottom: 2em; }
menu .drawer-list li a {
  text-decoration: none;
  color: #FEFEFE;
  text-align: center;
  display: block;
 padding: .5rem;
  font-size: 1.2em;
}
menu .drawer-list li a:hover {
  cursor: pointer;
  background-color: #88c2f8;
  background-color: rgba(17, 132, 240, 0.5);
}

The checkbox & label hack for the menu toggle.

menu input[type=checkbox] { display: none; }
menu input[type=checkbox]:checked + .drawer-list {
  transform: translatex(0);
  border-bottom-left-radius: 0;
}
menu input[type=checkbox]:checked + .drawer-list li { transform: translatex(0); }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(1) { transition: transform 0.5s 0.02s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(2) { transition: transform 0.5s 0.04s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(3) { transition: transform 0.5s 0.06s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(4) { transition: transform 0.5s 0.08s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(5) { transition: transform 0.5s 0.1s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(6) { transition: transform 0.5s 0.12s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(7) { transition: transform 0.5s 0.14s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(8) { transition: transform 0.5s 0.16s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(9) { transition: transform 0.5s 0.18s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(10) { transition: transform 0.5s 0.2s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(11) { transition: transform 0.5s 0.22s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(12) { transition: transform 0.5s 0.24s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(13) { transition: transform 0.5s 0.26s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(14) { transition: transform 0.5s 0.28s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(15) { transition: transform 0.5s 0.3s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(16) { transition: transform 0.5s 0.32s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(17) { transition: transform 0.5s 0.34s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(18) { transition: transform 0.5s 0.36s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(19) { transition: transform 0.5s 0.38s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(20) { transition: transform 0.5s 0.4s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(21) { transition: transform 0.5s 0.42s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(22) { transition: transform 0.5s 0.44s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(23) { transition: transform 0.5s 0.46s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(24) { transition: transform 0.5s 0.48s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(25) { transition: transform 0.5s 0.5s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(26) { transition: transform 0.5s 0.52s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(27) { transition: transform 0.5s 0.54s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(28) { transition: transform 0.5s 0.56s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(29) { transition: transform 0.5s 0.58s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(30) { transition: transform 0.5s 0.6s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(31) { transition: transform 0.5s 0.62s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(32) { transition: transform 0.5s 0.64s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(33) { transition: transform 0.5s 0.66s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(34) { transition: transform 0.5s 0.68s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(35) { transition: transform 0.5s 0.7s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(36) { transition: transform 0.5s 0.72s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(37) { transition: transform 0.5s 0.74s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(38) { transition: transform 0.5s 0.76s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(39) { transition: transform 0.5s 0.78s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(40) { transition: transform 0.5s 0.8s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(41) { transition: transform 0.5s 0.82s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(42) { transition: transform 0.5s 0.84s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(43) { transition: transform 0.5s 0.86s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(44) { transition: transform 0.5s 0.88s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(45) { transition: transform 0.5s 0.9s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(46) { transition: transform 0.5s 0.92s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(47) { transition: transform 0.5s 0.94s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(48) { transition: transform 0.5s 0.96s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(49) { transition: transform 0.5s 0.98s ease; }
menu input[type=checkbox]:checked + .drawer-list li:nth-child(50) { transition: transform 0.5s 1s ease; }
menu input[type=checkbox]:checked + .drawer-list li a { padding-right: 15px; }
menu input[type=checkbox]:checked ~ hamburger > i {
  background-color: transparent;
  transform: rotate(90deg);
}
menu input[type=checkbox]:checked ~ hamburger > i:before { transform: translate(-50%, -50%) rotate(315deg); }
menu input[type=checkbox]:checked ~ hamburger > i:after { transform: translate(-50%, -50%) rotate(-315deg); }
menu input[type=checkbox]:checked ~ hamburger close {
  color: #FEFEFE;
  width: 100%;
}
menu input[type=checkbox]:checked ~ hamburger open {
  color: transparent;
  width: 0;
}

Style the hamburger toggle icon.

menu hamburger {
  position: absolute;
  display: block;
  top: 20px;
  right: 20px;
  height: 50px;
  width: 50px;
}
menu hamburger:hover { cursor: pointer; }
menu hamburger text close, menu hamburger text open {
  text-transform: uppercase;
  font-size: .8em;
  align-text: center;
  position: absolute;
  transform: translateY(50px);
  text-align: center;
  overflow: hidden;
  transition: width .25s .35s, color .45s .35s;
}
menu hamburger text close {
  color: transparent;
  right: 0;
  width: 0;
}
menu hamburger text open {
  color: #FEFEFE;
  width: 100%;
}
menu hamburger > i {
  position: absolute;
  width: 100%;
  height: 2px;
  top: 50%;
  background-color: #FEFEFE;
  pointer-events: auto;
  transition-duration: .35s;
  transition-delay: .35s;
}
menu hamburger > i:before, menu hamburger > i:after {
  position: absolute;
  display: block;
  width: 100%;
  height: 2px;
  left: 50%;
  background: #FEFEFE;
  content: "";
  transition: transform 0.35s;
  transform-origin: 50% 50%;
}
menu hamburger > i:before { transform: translate(-50%, -14px); }
menu hamburger > i:after { transform: translate(-50%, 14px); }

Make the menu fully responsive to fit any screens.

@media (min-width: 768px) {
menu .drawer-list { width: 25vw; }
}

@media (min-width: 768px) {
menu .drawer-list li a {
  font-size: 1rem;
  text-align: right;
}
}