html{
	box-sizing: border-box;
}

body{
	background-color: rgb(240,240,240);
	padding-top: 50px;
}

h1 {text-align:center; margin-bottom: 15px;}

#box{
	width: 100%;
	height: 100%;
	background-color: rgb(220,220,220);
	overflow: hidden;
}

a{display: block;text-align:center; margin-bottom: 40px;}

input[type="submit"]{
	cursor:pointer;
}

.flashcard{
	position: absolute;
	width: 100%;
	height: 100%;
	-webkit-animation-duration: 0.5s;
	animation-duration: 0.5s;
	background-color: white;
	overflow: hidden;
}

.flashcard h2, .flashcard p{
	position: absolute;

	font-size: 4em;
	top: 50%;
	left: 50%;

	transform: translate(-50%, -50%);
}

.flashcard h2{font-size: 8em;}

#flashcard_position{
	position: relative;
	height: 60vh;
	width: 80%;
	margin: auto;
	top: 10vh;
}

.hidden{
	display: none;
}


.button_b{
	position:absolute;
	top: 100%;
	cursor:pointer;
	color: rgb(30,30,30);
	text-align: center;
	height:20vh;
}

.button_b p{
	position: absolute;
	top: 50%;
	left: 50%;
	transform: translate(-50%, -50%);
	font-size: 5em;
	margin: 0px;
	padding: 0px;
}

.b_next{
	right: 0px;
	left: 50%;
	background-color: rgb(85,240,185);
}

.b_next:hover{
	background-color: rgb(100,255,200);
}

.b_prev{
	left:0px;
	right: 50%;
	background-color: rgb(240,135,135);
}

.b_prev:hover{
	background-color: rgb(255,150,150);
}

#main{
	margin: auto;
	position: relative;
	width: 100%;
	height: 80vh;
}

.flashcard_A_side{
	position:absolute;
	height: 100%;
	width: 100%;
	background-color: white;
}

.flashcard_B_side{
	position:absolute;
	height: 100%;
	width: 100%;
	background-color: rgb(100,100,100);
	color: white;
	top: 100%;
	transition: top 0.2s linear;
}

.visible{
	top: 0%;
}


@media screen and (orientation: landscape){

	#flashcard_position{
		width: 60%;
		top: 10vh;
		height: 80vh;
	}

	.button_b{
		height: initial;
		top: 0px;
		bottom:0px;
		width: 5em;
	}

	.b_next{
		right: 0px;
		left: inherit;
	}

	.b_prev{
		left:0px;
		right: inherit;
	}

	#main{
		width: 100%;
		height: 100vh;
	}

}

@media screen and (min-width: 640px){

	#flashcard_position{
		width: 50%;
		height: 30vh;
		top: 15vh;
	}

	.button_b{
		height: initial;
		top: 0px;
		bottom: 0px;
		width: 5em;
	}

	.b_next{
		right: 0px;
		left: inherit;
	}

	.b_prev{
		left:0px;
		right: inherit;
	}

	#main{
		width: 70%;
		height: 60vh;
	}

}