html {
	height: 100%;
}
body {
	height: 100%;
  background: #20262E;
  font-family: Helvetica;
	background: #ccc;
}

.box {
	height: 100%;
	width: 640px;
	margin: 0 auto;
	position: relative;
	background: green;
}
button {
  background: #0084ff;
  border: none;
  border-radius: 5px;
  padding: 8px 14px;
  font-size: 15px;
  color: #fff;
}

.modal {
	display: none;
	position: fixed;
	width: 100%;
	max-width: 640px;
	top: auto;
	left: 50%;
	right: auto;
	bottom: 0;
	z-index: 2;
	background:red;
	transform: translate3d(-50%,0,0);
}
.title {
	 font-size: 14px;
	 text-align: center;
	}
.modal-content {
	padding: 20px 0;
}
input {
	width: 80%;
	height: 60px;
	display:block;
	margin: 0 auto;
}