*{
	margin: 0;
	padding: 0;
	-ms-box-sizing: border-box;
	-o-box-sizing: border-box;
	box-sizing: border-box;
}
body, html{
	background-color: #DDD;
	font-size: 16px;
	height: 100vh;
	width: 100vw;
	/*flex*/
	display: -webkit-box;
	display: -ms-flexbox;
	display: flex;
	-webkit-box-orient: vertical;
	-webkit-box-direction: normal;
	-ms-flex-direction: column;
	flex-direction: column;
	-webkit-box-pack: center;
	-ms-flex-pack: center;
	        justify-content: center;
	-webkit-box-align: center;
	-ms-flex-align: center;
	        align-items: center;
}
button{
	background-color: #FF0000;
	border: 1px solid #000;
	border-radius: 7px;
	color: #FF5;
	cursor: pointer;
	font-size: 20px;
	padding: 0.5rem;
}
button:hover{
	text-decoration: underline;
}
img{
	height: 100%;
	display: block;
	width: 100%;
}
.contenedor{
	height: 250px;
	width: 250px;
	margin-bottom: 1rem;
	-ms-perspective: 700;
	-o-perspective: 700;
	-webkit-perspective: 700;
	perspective: 700;

}
.carta{
	height: 100%;
	width: 100%;
	position: relative;
	-webkit-transform-style: preserve-3d;
	        transform-style: preserve-3d;
	-webkit-transition: 2s;
	transition: 2s;
}
.clase-girar{
	-webkit-transform: rotateY(180deg);
			transform: rotateY(180deg);
}
.lado{
	width: 100%;
	height: 100%;
	backface-visibility: hidden;
	position: absolute;
}
.frente{
	-webkit-transform: rotateY(180deg);
			transform: rotateY(180deg);
}