Clean Application - Hamburger Menu

clap-nav.css

nav {
  display: block;
  float: right;
  left: -1em;
  padding-top: .2em;
  position: absolute;
  user-select: none;
  width: 100%;
  z-index: 1;
  -webkit-user-select: none;
}

nav input,
nav .hamburger {
  height: 32px;
  position: absolute;
  right: 0;
  width: 40px;
}

nav input {
  display: block;
  opacity: 0;
  z-index: 2;
  -webkit-touch-callout: none;
}

nav .hamburger span,
nav .hamburger span:before,
nav .hamburger span:after {
  border-radius: 4px;
  height: 2px;
  position: absolute;
  transition: transform .15s ease;
  width: 35px;
}

nav .hamburger span {
  display: block;
  margin-top: 8px;
  transition-duration: .4s;
  transition-timing-function: cubic-bezier(.68, -.55, 0.265, 1.55);
}

nav .hamburger span:before,
nav .hamburger span:after {
  content: "";
  display: block;
}

nav .hamburger span:before {
  top: 10px;
  transition: opacity .15s .4s ease;
}

nav .hamburger span:after {
  bottom: -10px;
  top: 20px;
  transition: transform .4s cubic-bezier(.68, -.55, .265, 1.55);
}

nav ul {
  bottom: 0;
  left: 0;
  list-style-type: none;
  opacity: 0;
  padding: 2.5em 1em;
  position: fixed;
  right: 0;
  top: 4em;
  transform-origin: 0% 0%;
  transform: translate(0, -200%);
  transition: transform 0.5s cubic-bezier(0.77, 0.2, 0.05, 1.0), opacity 0.5s ease-out;
  text-align: right;
  width: 100%;
  -webkit-font-smoothing: antialiased;
  z-index: 99;
}

nav input:checked ~ ul {
  opacity: .95;
  transform: none;
  z-index: 99;
}

nav input:checked ~ .hamburger span {
  transform: translate3d(0, 10px, 0) rotate(135deg);
  transition-delay: 0.1s;
}

nav input:checked ~ .hamburger span:before {
  opacity: 0;
  transition-delay: 0s;
}

nav input:checked ~ .hamburger span:after {
  transform: translate3d(0, -20px, 0) rotate(-270deg);
  transition-delay: .1s;
}

nav .menu a {
  display: inline-block;
  margin: 1em 0 0;
  padding: 1em 1em .8em;
  text-decoration: none;
  text-transform: uppercase;
}

nav .menu .active,
nav .menu :active {
  border-radius: 3px;
}

@media only screen and (min-width: 768px) {
  nav .hamburger {display: none;}
  nav, nav ul  {padding: 0; position: static; margin: 0; width: auto;}
  nav ul {opacity: 1; margin-top: -1em; transform: none; transition: none;}
  nav li {display: inline-block;}
  nav .menu .active {margin: 1em;}
}