Login with Input Animation

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
  	<section class="content">
      <div class="container">
        <div class="center-content">

          <div class="box-login">

                <span class="input input--hoshi">
        					<input class="input__field input__field--hoshi" type="text" id="input-4" placeholder="">
        					<label class="input__label input__label--hoshi input__label--hoshi-color-1" for="input-4">
        						<span class="input__label-content input__label-content--hoshi">E-mail</span>
        					</label>
        				</span>
                <br>

                <span class="input input--hoshi">
        					<input class="input__field input__field--hoshi" type="password" id="input-4">
        					<label class="input__label input__label--hoshi input__label--hoshi-color-1" for="input-4">
        						<span class="input__label-content input__label-content--hoshi">Senha</span>
        					</label>
        				</span>
              </div>


              <div class="row">
                <div class="col-md-12">
                   <a href="#" class="btn btn-default">Entrar</a>
                </div>
              </div>
                </div>

      </div>
      </section>

CSS

@import url(https://fonts.googleapis.com/css?family=Open+Sans);




.container {
	margin: 0 auto;
	text-align: center;
	overflow: hidden;
}

.content {
	font-size: 150%;
	padding: 3em 0;
}

.content h2 {
	margin: 0 0 2em;
	opacity: 0.1;
}

.content p {
	margin: 1em 0;
	padding: 5em 0 0 0;
	font-size: 0.65em;
}


  .center-content{
    width : 100vw;
    height : 70vh;
    display : table-cell;
    vertical-align : middle;
    float:none;
    }


    body{
      background-color:#8e44ad;
      color: #3498db;
      font-family: "Open Sans", sans-serif;
    }

    a{color:#eee;text-decoration:none;}
    a:hover{color:#f1c40f;text-decoration: none;}

.input {
	position: relative;
	z-index: 1;
	display: inline-block;
	margin: 1em;
	max-width: 350px;
	width: calc(100% - 2em);
	vertical-align: top;
}

.input__field {
	font-size: 1.5em;
  letter-spacing: 1px;
	position: relative;
	display: block;
	float: right;
	padding: 0.8em;
	width: 60%;
	border: none;
	border-radius: 0;
	background: #f0f0f0;
	color: #aaa;
	font-weight: bold;
	font-family: "Open Sans", sans-serif;
	-webkit-appearance: none; /* for box shadows to show on iOS */
}

.input__field:focus {
	outline: none;
}

.input__label {
	display: inline-block;
	float: right;
	padding: 0 1em;
	width: 40%;
	color: #f1c40f;
	/*font-weight: bold;*/
	font-size: 70.25%;
	-webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
	-webkit-touch-callout: none;
	-webkit-user-select: none;
	-khtml-user-select: none;
	-moz-user-select: none;
	-ms-user-select: none;
	user-select: none;
}

.input__label-content {
	position: relative;
	display: block;
	padding: 1.6em 0;
	width: 100%;
}

.graphic {
	position: absolute;
	top: 0;
	left: 0;
	fill: none;
}

.icon {
	color: #ddd;
	font-size: 150%;
}



/* Hoshi */
.input--hoshi {
	overflow: hidden;
}

.input__field--hoshi {
	margin-top: 1em;
	padding: 0.85em 0.15em;
	width: 100%;
	background: transparent;
	color: #fff;
}

.input__label--hoshi {
	position:...