<div class="wrapper">
	<div class="container">
		<h1>Welcome</h1>
		<form class="form">
			<input type="text" placeholder="Username">
			<input type="password" placeholder="Password">
			<button type="submit" id="login-button">Login</button>
		</form>
	</div>
	
	<ul class="bg-bubbles">
		<li></li>
		<li></li>
		<li></li>
		<li></li>
		<li></li>
		<li></li>
		<li></li>
		<li></li>
		<li></li>
		<li></li>
	</ul>
</div>
@import url(https://fonts.googleapis.com/css?family=Source+Sans+Pro:200,300);
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-weight: 300;
}
body {
  font-family: 'Source Sans Pro', sans-serif;
  color: white;
  font-weight: 300;
}
body ::-webkit-input-placeholder {
  /* WebKit browsers */
  font-family: 'Source Sans Pro', sans-serif;
  color: white;
  font-weight: 300;
}
body :-moz-placeholder {
  /* Mozilla Firefox 4 to 18 */
  font-family: 'Source Sans Pro', sans-serif;
  color: white;
  opacity: 1;
  font-weight: 300;
}
body ::-moz-placeholder {
  /* Mozilla Firefox 19+ */
  font-family: 'Source Sans Pro', sans-serif;
  color: white;
  opacity: 1;
  font-weight: 300;
}
body :-ms-input-placeholder {
  /* Internet Explorer 10+ */
  font-family: 'Source Sans Pro', sans-serif;
  color: white;
  font-weight: 300;
}
.wrapper {
  background: #50a3a2;
  background: linear-gradient(top left, #50a3a2 0%, #53e3a6 100%);
  background: linear-gradient(to bottom right, #50a3a2 0%, #53e3a6 100%);
  position: absolute;
  top: 50%;
  left: 0;
  width: 100%;
  height: 400px;
  margin-top: -200px;
  overflow: hidden;
}
.wrapper.form-success .container h1 {
          transform: translateY(85px);
}
.container {
  max-width: 600px;
  margin: 0 auto;
  padding: 80px 0;
  height: 400px;
  text-align: center;
}
.container h1 {
  font-size: 40px;
  transition-duration: 1s;
  transition-timing-function: ease-in-     put;
  font-weight: 200;
}
form {
  padding: 20px 0;
  position: relative;
  z-index: 2;
}
form input {
          appearance: none;
  outline: 0;
  border: 1px solid rgba(255, 255, 255, 0.4);
  background-color: rgba(255, 255, 255, 0.2);
  width: 250px;
  border-radius: 3px;
  padding: 10px 15px;
  margin: 0 auto 10px auto;
  display: block;
  text-align: center;
  font-size: 18px;
  color: white;
  -webkit-transition-duration: 0.25s;
          transition-duration: 0.25s;
  font-weight: 300;
}
form input:hover {
  background-color: rgba(255, 255, 255, 0.4);
}
form input:focus {
  background-color: white;
  width: 300px;
  color: #53e3a6;
}
form button {
          appearance: none;
  outline: 0;
  background-color: white;
  border: 0;
  padding: 10px 15px;
  color: #53e3a6;
  border-radius: 3px;
  width: 250px;
  cursor: pointer;
  font-size: 18px;
  transition-duration: 0.25s;

}
form button:hover {
  background-color: #f5f7f9;
}
.bg-bubbles {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}
.bg-bubbles li {
  position: absolute;
  list-style: none;
  display: block;
  width: 40px;
  height: 40px;
  background-color: rgba(255, 255, 255, 0.15);
  bottom: -160px;
  animation: square 25s infinite; 
  transition-timing-function: linear;
}
.bg-bubbles li:nth-child(1) {
  left: 10%;
}
.bg-bubbles li:nth-child(2) {
  left: 20%;
  width: 80px;
  height: 80px;
  animation-delay: 2s;
  animation-duration: 17s;
}
.bg-bubbles li:nth-child(3) {
  left: 25%;
  animation-delay: 4s;
  
}
.bg-bubbles li:nth-child(4) {
  left: 40%;
  width: 60px;
  height: 60px;
  animation-duration: 22s;
  background-color: rgba(255, 255, 255, 0.25);
}
.bg-bubbles li:nth-child(5) {
  left: 70%;
}
.bg-bubbles li:nth-child(6) {
  left: 80%;
  width: 120px;
  height: 120px;
  animation-delay: 3s;
  background-color: rgba(255, 255, 255, 0.2);
}
.bg-bubbles li:nth-child(7) {
  left: 32%;
  width: 160px;
  height: 160px;
  animation-delay: 7s;
}
.bg-bubbles li:nth-child(8) {
  left: 55%;
  width: 20px;
  height: 20px;
  animation-delay: 15s;
  animation-duration: 40s;
}
.bg-bubbles li:nth-child(9) {
  left: 25%;
  width: 10px;
  height: 10px;
  animation-delay: 2s;
  animation-duration: 40s;
  background-color: rgba(255, 255, 255, 0.3);
}
.bg-bubbles li:nth-child(10) {
  left: 90%;
  width: 160px;
  height: 160px;
  animation-delay: 11s;        
}
@keyframes square {
  0% {
    transform: translateY(0);
  }
  100% {
    transform: translateY(-700px) rotate(600deg);
  }
}
@keyframes square {
  0% {
            transform: translateY(0);
  }
  100% {
            transform: translateY(-700px) rotate(600deg);
  }
}
 $("#login-button").click(function(event){
		 event.preventDefault();
	 
	 $('form').fadeOut(500);
	 $('.wrapper').addClass('form-success');
});

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. //cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js