styles.css

@import url(https://fonts.googleapis.com/css?family=Open+Sans:600);

.frame {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 400px;
  height: 400px;
  margin-top: -200px;
  margin-left: -200px;
  border-radius: 2px;
  box-shadow: 1px 2px 10px 0px rgba(0,0,0,0.3);
  background: #2c3e50;
  font-family: 'Open Sans', Helvetica, sans-serif;
  overflow: hidden;
}

.circle, .circle-outer {
	position: absolute;
	width: 200px;
	height: 200px;
	top: 65px;
	left: 100px;
	border-radius: 50%;
}

.circle{
	background: #354A5F;
}

.circle-outer {
	box-sizing: border-box;
	background: none;
	border: 4px solid #354A5F;
}

.icon {
	position: absolute;
	z-index: 2;
	top: 130px;
	left: 140px;
	transform: translate3d(0,0,0);
	fill: none;
	stroke-width: 2px;
	stroke: #ecf0f1;
	stroke-linecap: square;
	stroke-dasharray: 325 325;
}
	
.icon.mail {
    width: 120px;
    height: 70px;
    stroke-dashoffset: 0;
}

.icon.plane {
    width: 120px;
    height: 110px;	
    stroke-dashoffset: 325;
}
	

#cb {
	display: none;
}

.button {
	position: absolute;
	z-index: 10;
	width: 200px;
	height: 40px;
	top: 290px;
	left: 100px;
	background: #ecf0f1;
	color: #2c3e50;
	text-align: center;
	line-height: 40px;
	border-radius: 20px;
	font-weight: 600;
	text-transform: uppercase;
	font-size: 15px;
	cursor: pointer;
}
		
.button.reset {
		opacity: 0;
		z-index: 5;
}
	
.button:hover {
    background: #1abc9c;
    color: #fff;
}

#cb:checked ~ .button {
	animation: button 1.5s ease-in-out 1.7s;
	animation-fill-mode: both;
}
#cb:checked ~ .reset {
	animation: reset 1s ease-in-out 3.7s;
	animation-fill-mode: both;
}

#cb:checked ~ .circle {
	animation: circle 1s ease-in-out;
	animation-fill-mode: both;
}

#cb:checked ~ .circle-outer {
	animation: circle .8s ease-in-out .2s;
	animation-fill-mode: both;
}

#cb:checked ~ .mail {
	stroke-dashoffset: 326;
	transition: stroke-dashoffset 1s ease-in-out;
}

#cb:checked ~ .plane {
	stroke-dashoffset: 0;
	transition: stroke-dashoffset 1s ease-in-out .6s;
	animation: fly 2.4s ease-in-out;
	animation-fill-mode: both;
}

@keyframes fly {
	0%, 50% {
		transform: translate3d(0,0,0) scale(1);
	}
	60% {
		transform: translate3d(-10px,5px,0) scale(1.05);
	}
	70% {
		opacity: 1;
	}
	85% {
		opacity: 0;
	}
	100% {
		transform: translate3d(300px,-150px,0) scale(0.4);
		opacity: 0;
	}
}

@keyframes circle {
	0% {
		transform: translate3d(0,0,0) scale(1);
	}
	20% {
		transform: scale(1.1);
	}
	100% {
		transform: scale(0);
	}
}

@keyframes button {
	0% {
		transform: scale(1);
	}
	30% {
		background: #1abc9c;
		color: transparent;
		width: 200px;
		left: 100px;
	}
	50%,60% {
		width: 40px;
		left: 180px;
		transform: scale(1);
	}
	70% {
		transform: scale(1.1);
	}
	100% {
		width: 40px;
		left: 180px;
		background: #1abc9c;
		color: transparent;
		transform: scale(0);
	}
}

@keyframes reset {
	from {
		opacity: 0;
	}
	to {
		opacity: 1;
	}
}