body{	font-family: Courier New, Monospace; 		}

#parent_div{
  height: 100vh;
  width:100vw;
  border: 0px dotted red;
  margin-left: 0vw; 
  margin-top: 0vw;
  margin-right: 5vw; 
  display:flex;
  background-color: lightgray;
}

.main_div{
  height:100vh;
  border: 0px   dotted green;
  background-color: white;
  padding-top: 5px;
  display: block;
  background-color:red;
}

#main_area{
	float:left;
	width:80vw;
	margin-top:3vh;
	margin-left:8vw;
	margin-right:8vw;
	padding:2vw;
	border: 1px   solid #a8aaac;
	color:  black;  font-weight: 400; 
	background-color: green;
}

#_video_area{
	float:left;
	width:80vw;
	display: none;
	height: 355px;

	margin-top:8vh;
	margin-left:8vw;
	margin-right:8vw;

	padding:2vw;

	border: 1px   solid #a8aaac;
	color:  black;  font-weight: 400; 
	text-align:center;
}

#button_area{
	float:left;
	width:80vw;
	margin-top:5vh;
	margin-left:8vw;
	margin-right:8vw;

	padding:0px;
	border: 0px   solid #a8aaac;
	color:  black;  font-weight: 400; 
	font-size: 3vh;
	
}

#contact_area{
  
	float:left;
	width:80vw;
	margin-top:25vh;
	margin-left:8vw;
	margin-right:8vw;
	
	text-align:center;
	padding:2vw;
	border: 1px   solid #a8aaac;
	color:  black; font-size: 2.2vh; font-weight: 400; 
}

.wiskundeonline-net{
	color:  #3663E4;  font-weight: 600; 
}

.button{
	margin-top:3vh;
	padding:1vw;
	text-align:center;
	border: 1px   solid #a8aaac;
}

#block_one{
	float:left;
	width:15vw;
	margin-left:0px;
}

#block_two{
	float:left;
	width:20vw;
	margin-left:14vw;
}

#block_three{
	float:right;
	width:17vw;
	margin-left:8vw;
}

#logo_wolnet{
	float:left;
	width:90vw;
	margin-left:4vw;
	margin-right:4vw;
	
	display: inline;
	background-color:white;
	border: 0px   solid greenyellow; 
    float: left;
}

#img_school{
	float:right;
	margin-top:1vw;
	background-color:white;
	border: 0px   solid blue; 
     
}

.vert_spacer_20{
  width:100%; height:2vh; float:right; 
  border: 0px   solid red; 
}

.nav_bar_coornhert{
	width:90vw;
	margin-left:4vw;
	margin-right:4vw;
	height: 2vh; 
	background-color:#a8aaac;
	border: 0px   solid blueviolet;
	float: left;  
}

#promo_video{
	width:200px;
}

  /* unvisited link */
  a:link {
	color: black;
  }
  /* visited link */
  a:visited {
	color: black;
  }
  /* mouse over link */
  a:hover {
	color: light-grey;
  }
  /* selected link */
  a:active {
	color: black;
  }