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HTML 

              
                <div class="window">
  <span class="shutters"></span>
  <span class="shutters"></span>

  <div class="bush">

    <div class="bird one">
      <span class="head"></span>
      <span class="body"></span>
      <span class="tail"></span>
    </div>

    <div class="bird two">
      <span class="head"></span>
      <span class="body"></span>
      <span class="tail"></span>
    </div>

  </div>
  
  <div class="ground"></div>
  
</div>

<h1>The Second Day of CSS-mas</h1>
<p>Press or hover over to open!</p>
!

CSS 

              
                $day-text-light:#b0302d;
$day-text-dark:#8d2623;

* {
  box-sizing:border-box;
  position:relative;
}
body {
  background:#333;
  background-image:repeating-linear-gradient(90deg,rgba(#567c15,.8),rgba(#567c15,.8) 5vmin,rgba(#a5be3e,.8) 5vmin,rgba(#a5be3e,.8) 10vmin);
  font-size:10px;
  perspective: 1000; /* Thanks to @davidmogar, this makes the shutters actually look like opening shutters. No complex 3d transforms needed! Everyone loves that. =D */
}
h1 {
  color:#fff;
  font-family:"Playfair Display";
  font-size:2rem;
  font-style:italic;
  margin:1.25rem auto;
  text-align:center;
  text-shadow:0 0 .5rem #000;
}
p {
  color:#fff;
  font-size:1rem;
  text-align:center;
  text-shadow:0 0 .5rem #000;
}
/* Window
--------------------*/
.window {
  background:#5eb3b3;
  border:2em solid #362f1f;
  height:25rem;
  margin:1rem auto 0;
  width:25rem;
}
.shutters {
  background:#532900;
  border:1px solid #281400;
  float:left;
  height:100%;
  overflow:hidden;
  transition:transform 800ms;
  width:50%;
  z-index:15;
}
.window:hover .shutters, .window:focus .shutters { /* Work on hover or touch. Cancel when input device is outside the window. */
  transform:rotateY(180deg); /* "Opens" the shutters. */
}
.window:hover .shutters:first-child, .window:focus .shutters:first-child {
  transform: rotateY(-180deg);
}
.shutters:nth-child(1) {
  transform-origin:0%; /* Set the "hinge" on the left-hand side. This is necessary because the default origin is 0,0 or center. */
}
.shutters:nth-child(2) {
  transform-origin:100%; /* Set the "hinge" on the right-hand side. */
}
/* day text
--------------------*/
.shutters:after {
  content:"2";
  color:#fff;
  font-family:"Playfair Display";
  font-size:18rem;
  position:absolute;
  top:-1rem;
}
.shutters:nth-child(1):after {
  color:$day-text-light;
  left:58%;
}
.shutters:nth-child(2):after {
  color:$day-text-dark;
  right:58%;
}
.window:hover .shutters:after, .window:focus .shutters:after {
  visibility:hidden;
  transition:visibility 220ms;
}
.window .shutters:after, .window .shutters:after {
  visibility:visible;
  transition:visibility 400ms 220ms;
}
/* Bird
--------------------*/
.bird {
  display:inline-block;
  position:absolute;
  transform:scaleX(-1) rotate(-45deg);
  z-index:10;
}
.bird.one {
  right:3rem;
  top:-3rem;
}
.bird.two {
  left:2rem;
  top:2rem;
}
.body {
  background:#bec3c6;
  border-radius:0 0 8rem 8rem;
  bottom:0rem;
  display:block;
  height:3.5rem;
  position:relative;
  width:7rem;
}
.body:before,
.body:after {
  border-radius:0 0 5rem 5rem;
  bottom:0;
  content:"";
  display:block;
  height:2.5rem;
  position:absolute;
  transform-origin:100% 0; /* Rotate the wings from a point on the body instead of the center of the element. */
  width:5rem;
}
.one .body:before {
  background:#9ea4a7;
  transform:rotate(85deg) scale(.8);
  z-index:-1;
}
.body:after {
  background:#b4b9bc;
  background:#a9aeb1;
}
.one .body:after {
  transform:rotate(45deg);
}
.two .body:after {
  top:0;
  right:2rem;
  z-index:2;
}
.head {
  background:#bec3c6;
  display:block;
  height:2.5rem;
  position:absolute;
  right:-1.5rem;
  width:2.5rem;
  z-index:1;
}
.one .head {
  border-radius:1rem 2rem 0 2rem;
}
.two .head {
  border-radius:0rem 2rem 1rem 2rem;
  right:0rem;
  top:-2rem;
}
.head:after {
  background:#fff;
  border-radius:100%;
  content:"";
  display:block;
  height:.5rem;
  left:1rem;
  position:absolute;
  top:1rem;
  width:.5rem;
}
.tail {
  border:.25rem solid transparent;
  border-left:2rem solid #bec3c6;
  display:block;
  height:2rem;
  left:-1.5rem;
  position:absolute;
  top:-.25rem;
  width:3rem;
}
/* Bush
--------------------*/
.bush {
  background:#27720e;
  border-radius:10rem;
  /* border-left:1rem solid #215e0d; */
  bottom:2rem;
  height:10rem;
  margin:0 2em;
  position:absolute;
  width:20rem;
}
.bush:before,.bush:after {
  background:#27720e;
  /* border-left:1rem solid #215e0d; */
  content:"";
  display:block;
  position:absolute;
}
.bush:before {
  height:8rem;
  border-radius:90% 100%;
  bottom:5rem;
  left:2rem;
  /* transform:rotate(90deg); */
  width:8rem;
}
.bush:after {
  border-radius:100% 80%;
  bottom:5rem;
  height:10rem;
  right:2rem;
  width:10rem;
}
.ground {
  background:#215f0c;
  bottom:0;
  height:3rem;
  position:absolute;
  width:100%;
}
!

JS
!
999px

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