<div class="wrapper">
<div class="container">
  <div class="topfold">
  </div>
  <div class="letter">
    <div class="upper">
      <div class="front">
      <h1>Sign Up</h1>
      <p>Get the latest updates and offers in your inbox!</p>
      </div>
      <div class="back">
      </div>
    </div>
    <form id="email"><input type="text"></input><span class="submitwrap"><input type="submit" value="DO IT"/></span></form>
  </div>
  </div>
<svg version="1.1" id="Capa_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
	 viewBox="0 0 58 32" style="enable-background:new 0 0 58 32;" xml:space="preserve">
<style type="text/css">
	.st0{fill:#D1D0BF;}
	.st1{fill:#E5E5DA;}
</style>
<g class="bottom">
	<polygon class="st0" points="0,32 0,0 21,16 	"/>
	<polygon class="st0" points="58,32 58,0 37,16 	"/>
	<path class="st1" d="M57,31.2L37,16H21L1,31.2c-0.4,0.3-1,0-1-0.5V32h58v-1.3C58,31.2,57.4,31.5,57,31.2z"/>
</g>
</svg>
</div>
@font-face{
    font-family:Head;
    font-weight:100;
    src:local(※), url(https://s3-us-west-2.amazonaws.com/s.cdpn.io/383755/wayfarer-regular-webfont.woff) format('woff');
}

$gray : #666;
$sans :'Quicksand', sans-serif;
$blue : #0000ff;
$red : #ce0010;


body{
  width:100vw;
  height:100vh;
  display:flex;
  justify-content:center;
  align-items:center;
  background: #16A085;
  font-family:$sans;
  color:$gray;
  overflow:hidden;
background: #E0EAFC; /* fallback for old browsers */
background: -webkit-linear-gradient(to bottom, #E0EAFC , #CFDEF3); /* Chrome 10-25, Safari 5.1-6 */
background: linear-gradient(to bottom, #E0EAFC , #CFDEF3); /* W3C, IE 10+/ Edge, Firefox 16+, Chrome 26+, Opera 12+, Safari 7+ */
        
  .wrapper{
    width:100%;
    max-width:400px;
    height:auto;
    position:relative;
    margin-top:20%;
    perspective: 800px;
    
    .container{
      display:block;
      width:100%;
      height:218px;
      background:#C4C2A5;
      position:absolute;
      bottom:5px;
      z-index:0;
      border-radius:10px;
      .topfold{
        width: 0;
        height: 0;
        position:relative;
        z-index:2;
        margin-top:-2px;
        border-style: solid;
        border-width: 160px 200px 0 200px;
        border-color: #e7e7de transparent transparent transparent;

      }
      .letter{
        position:absolute;
        width:calc(100% - 10px);
        height:100px;
        bottom:5px;
        left:5px;
        z-index:3;
        background:
#faf5f3;
        border-top:1px solid #faf5f3;
        box-shadow:0px 10px 15px -5px rgba(0,0,0,0.25);
        transition:0.2s ease-in-out;
        form{
          position:absolute;
          width:auto;
          bottom:20px;
          left:50%;
          transform:translateX(-50%);
          z-index:1;
          input[type="text"]{
            font-size:1.2em;
            padding:5px;
            border:0px solid;
            background:transparent;
            border-bottom:5px solid $red;
            &:focus{
              -webkit-outline:none;
              outline: none;
              border-bottom:5px solid $blue;
            }
          }
          .submitwrap{
            display:table;
            padding:5px;
            margin:15px auto 0px;
            background: $blue;
            &:hover{
              input{
                color:$red;
              }
              background: repeating-linear-gradient(
  45deg,
  #ce0010,
  #ce0010 5px,
  #ffffff 5px,
  #ffffff 10px, #0000ff 10px, #0000ff 15px, #ffffff 15px, #ffffff 15px
);
              animation: animatedBackground 40s linear infinite;
              @keyframes animatedBackground {
            from { background-position: 0 0; }
            to { background-position: 500px 0; }
          }
            }
          }
          input[type="submit"]{
            color:$blue;
            background:#fff;
            font-family:head;
            border:0px solid;
            padding:5px 10px;
            font-size:1.2em;
            display:block;
            margin:0px auto 0;
          }
        }
        &:before{
            content:'';
            position:absolute;
            bottom:0;
            left:0;
            width:100%;
            height:5px;
            background: repeating-linear-gradient(
  45deg,
  #ce0010,
  #ce0010 5px,
  #ffffff 5px,
  #ffffff 10px, #0000ff 10px, #0000ff 15px, #ffffff 15px, #ffffff 15px
);
        }
        .upper{
          position:absolute;
          display:block;
          height:100%;
          width:100%;
          top:-100%;
          backface-visibility:hidden;
          transform-style: preserve-3d;
          left:0;
          border-bottom:1px solid #faf5f3;
          -webkit-backface-visibility:hidden;
          z-index:2;
          .back{
            position:absolute;
            width:100%;
            height:100%;
            background:#f8f8f8;
            top:100%;
            transform-origin:50% 0%;
            transform:rotateX(0deg);
            backface-visibility:hidden;
          }
          .front{
            position:absolute;
            display:block;
            box-shadow:0px 10px 50px rgba(0,0,0,0.05), inset 0px -25px 50px -25px rgba(0,0,0,0.16);
            background:#fff;
            width:100%;
            height:100%;
             top:100%;
            transform:rotateX(-180deg);
            backface-visibility:hidden;
          &:before{
            content:'';
            position:absolute;
            top:0;
            left:0;
            width:100%;
            height:5px;
            background: repeating-linear-gradient(
  45deg,
  #ce0010,
  #ce0010 5px,
  #ffffff 5px,
  #ffffff 10px, #0000ff 10px, #0000ff 15px, #ffffff 15px, #ffffff 15px
);
          }
          }
          h1{
            color:$red;
            font-family:head;
            padding:0px 20px;
            margin-bottom:0px;
            line-height:1;
          }
          p{
            padding:0px 35px;
            margin-top:0px;
            color:$blue;
            font-weight:800;
            font-size:1.2em;
          }
        }
      }
    }
    svg{
      max-width:100%;
      position:relative;
      z-index:0;
      bottom:0;
      box-shadow:0px 10px 20px -5px rgba(0,0,0,0.25);
    }
    
  }
}
View Compiled
var tl = new TimelineMax({
  repeat: 0,
  delay: 0
});


tl.to(".topfold", 0.5,  {transformOrigin:"50% 0%", x:0, y:0, fill:'#d5d3bb', scaleY:-1, delay:0, ease: Circ.easeIn});
tl.to(".letter", 0.5,  {x:0, y:-140, delay:0, height:125, ease: Circ.easeOut});
tl.to(".upper", 1.2,  {x:0, transformOrigin:"50% 100%", rotationX:-180, delay:0.3, height:125, ease: Circ.easeOut});
tl.to(".letter", 0.5,  {x:0, y:-200, rotationX:0, delay:0, ease: Circ.easeInOut});

$( "#email" ).submit(function( event ) {
  event.preventDefault();
  var tl2 = new TimelineMax({
  repeat: 0,
  delay: 0
});
  
tl2.to(".upper", 1,  {x:0, transformOrigin:"50% 100%", rotationX:0, delay:0, height:125, ease: Circ.easeIn});
tl2.to(".letter", 1,  {x:0, y:0, rotationX:0, scaleY:0.5, delay:0, ease: Expo.easeOut});
tl2.to(".topfold", 0.6,  {transformOrigin:"50% 0%", scaleY:1, delay:0, ease: Circ.easeIn});
tl2.to(".wrapper", 0.7,  {transformOrigin:"50% 0%", x:5000, y:0, delay:0, ease: Circ.easeIn});


});

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.0/jquery.min.js
  2. https://cdnjs.cloudflare.com/ajax/libs/gsap/1.19.0/TweenMax.min.js