/* I always reset all the html elements */
*{
	margin: 0;
	padding: 0;
	box-sizing: border-box;
}

body{
	font-family: sans-serif;
	min-height: 100vh;
	color: #555;
	padding-top: 30px;
	background-color: white;
}

.example{
	width:  300px;
	margin: 0 auto;
	text-align: center;
}

.box{
	width:  300px;
	height:  200px;
	background-color: #333;
	transition: opacity .5s;
	margin-bottom: 20px;
}

.box.fade-out{
	opacity: 0;
}

button{
	padding: 10px 30px;
	font-size: 15px;
	display: inline-block;
}

#fade-out-trigger{
	margin-right: 10px;
}
#fade-in-trigger{
	margin-left: 10px;
}