style.scss

@import 'https://fonts.googleapis.com/css?family=Source+Sans+Pro:700';

$font:'cursive', sans-serif;
$primary:#FF0072;
$second:rgb(93,205,136);
$third:#4426a8;
  
*,
*::before,
*::after {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

html, body{
    height:100%;
    width: 200px;
}

h3{
    color:$second
}

body {
  padding:0px;
  margin:0;
  text-align: center;
  font-family:$font;
  background:#24252A;
  -webkit-font-smoothing: antialiased;
}

.flex {
  display:flex;
  align-items:center;
  justify-content:center;
}

.btn {
  color:$second;
  background-color: #24252A;
  text-decoration:none;
  -webkit-transition:0.3s all ease;
  transition:0.3s ease all;
  &:hover {
    color:#FFF;
  }
  &:focus {
    color:#FFF;
  }
}

.btn {
  font-size:10px;
  width:50%;
  letter-spacing:2px;
  text-transform:uppercase;
  display:inline-block;
  text-align:center;
  font-weight:bold;
  padding:5px 0px;
  border:3px solid $second;
  border-radius:2px;
  position:relative;
  box-shadow: 0 2px 5px rgba(0,0,0,0.16), 0 3px 6px rgba(0,0,0,0.1);
  z-index:2;
  &:before {
    -webkit-transition:0.5s all ease;
    transition:0.5s all ease;
    position:absolute;
    top:0;
    left:50%;
    right:50%;
    bottom:0;
    opacity:0;
    content:'';
    background-color:$second;
    z-index:-1;
  }
  &:hover {
    &:before {
      -webkit-transition:0.5s all ease;
      transition:0.5s all ease;
      left:0;
      right:0;
      opacity:1;
    }
  }
  &:focus {
    &:before {
      -webkit-transition:0.5s all ease;
      transition:0.5s all ease;
      left:0;
      right:0;
      opacity:1;
    }
  }
}

.input-container{
	position:relative;
    margin-bottom:15px;
}
.input-container label{
	position:absolute;
	top:0px;
	left:0px;
	font-size:15px;
	color:#fff;	
	transition: all 0.5s ease-in-out;
}
.input-container input{ 
  border:0;
  border-bottom:1px solid #555;  
  background:transparent;
  width:100%;
  padding:8px 0 5px 0;
  font-size:15px;
  color:#fff;
}
.input-container input:focus{ 
 border:none;	
 outline:none;
 border-bottom:1px solid rgb(93,205,136);	
}

.input-container input:focus ~ label,
.input-container input:valid ~ label{
	top:-10px;
	font-size:10px;
	
}