body{
	font-family: 'Lato', 'Open Sans';
	font-size: 16px;
}

div.null{
	display: none;
}


div.period{
	display: block;
	position: relative;
	left: 10vw;
	margin-top: 10vw;

	width: 80vw;
	height: 54vw;

	background: red;
	border: 1px solid black;
}

div.period > .title{
	display: inline-block;
	position: absolute;
	margin-top: -1.2em;
	left: 50%;

	transform: translateX(-50%);

	font-size: 1.2em;
}

div.period > [class^=d]{
	display: block;
	position: absolute;
	top: 0;
	left: 0;

	width: calc( 80vw / 5 - 1px );
	height: 100%;

	border-right: 1px solid black;

	background-color: #F8F8F8;
}

div.period > .d1{
	left: 20%;
}

div.period > .d2{
	left: 40%;
}

div.period > .d3{
	left: 60%;
}

div.period > .d4{
	left: 80%;
	border-right: none;
	width: calc( 80vw / 5 );
}

div.period > [class^=d] > .course{
	display: block;
	position: absolute;
	top: 0;
	left: 0;

	width: 100%;
	height: 0;

	font-size: 1.2vw;
}

div.period > [class^=d] > .course > .start{
	display: inline-block;
	position: absolute;
	top: 1px;
	left: 1px;
}

div.period > [class^=d] > .course > .stop{
	display: inline-block;
	position: absolute;
	bottom: 1px;
	right: 1px;
}

div.period > [class^=d] > .course > .container{
	display: flex;
	position: absolute;
	top: 0;
	left: 0;

	width: 100%;
	height: 100%;

	flex-direction: column;
	flex-wrap: nowrap;
	justify-content: center;
	align-items: center;
}

div.period > [class^=d] > .course > .container *{
	text-align: center;
}