*{box-sizing: border-box;}

body {background-color: #d9d9d9;
	  color: #000000;
	  font-family: sans-serif;}

#wrapper {margin-left: auto;
		  margin-right: auto;
		  background-image: linear-gradient(to bottom, #ffffff, #90c7e3;)
		  background-repeat: no-repeat;
		  width: 80%;
		  min-width: 960px;
		  max-width: 2048px;
		  box-shadow: 4px 4px 4px 4px #262626;
		  border: 2px solid #000003}
		  
header {background-color: #d9d9d9;
		color: #000000;
		height: 100px;
		text-align: center;
		padding-top: 20px;}
	
h1 {margin-bottom: 0;
	margin-top: 0;
	font-family: impact, fantasy;
	font-size: 2em;
	letter-spacing: .25em;}
	
nav {float: left;
	 font-weight: normal;
	 padding: 1.5em;
	 font-size: 125%;
	 width: 180px;}
	 
nav ul {list-style-type:none;
        margin: 0;
        padding-left: 0;
        font-size: 1em;}
	 
nav a {text-decoration: none;}

main {background-color: #d9d9d9;
	 padding: 1px 20px 20px 30px;
	 display: block;
	 margin-left: 180px;
	 overflow: auto;}
	 
#circuit {height: 300px;
		  background-image: url(circuit.jpg);
		  background-size: 100% 100%;
		  background-repeat: no-repeat;
		  margin-left: 180px;}

#computer {height 300px;
		   background-image: url(computer.jpg);
		   background-size: 100% 100%;
		   background-repeat: no-repeat;
		   margin-left: 180px;}
		   
footer {font-size: 75%;
		text-align: left;}