Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.3.3)
// Compass (v1.0.0.alpha.18)
// ----

%transition {
  -webkit-transition :0.5s ease all;
  transition         :0.5s ease all;
  position           :absolute;
  left               :0;
  right              :0;
  height             :600px;
}

.container {
  &.ng-enter {
    @extend %transition;
    z-index :100;
    left    :600px;
    opacity :0;
    &.ng-enter-active {
      left:0;
      opacity:1;
    }
  }
  &.ng-leave {
    @extend %transition;
    z-index:101;
    left:0;
    opacity:1;
    &.ng-leave-active {
      left:-600px;
      opacity:0;
    }
  }
}

SassMeister-output.css

.container.ng-enter, .container.ng-leave {
  -webkit-transition: 0.5s ease all;
  transition: 0.5s ease all;
  position: absolute;
  left: 0;
  right: 0;
  height: 600px;
}

.container.ng-enter {
  z-index: 100;
  left: 600px;
  opacity: 0;
}
.container.ng-enter.ng-enter-active {
  left: 0;
  opacity: 1;
}
.container.ng-leave {
  z-index: 101;
  left: 0;
  opacity: 1;
}
.container.ng-leave.ng-leave-active {
  left: -600px;
  opacity: 0;
}

@ovidiubuligan yes they added the % aka placeholder in 3.2.0
http://sass-lang.com/documentation/file.SASS_CHANGELOG.html#320_10_august_2012