*{margin:0;}

#contenedor{
    width:960px;
margin:0 auto;}

body{
    width:960px;
height: auto}

header{
    width:960px;}

#titulo { margin-left:200px;
    margin-top: 20px;
          width:590px;}

nav{
    list-style-type: none;
       height: 50px;
       width: 450px;
margin-left: 250px;
padding-top: 30px;}

nav ul{width: 400px;
height: 50px;}

nav li {
    display: inline;
    float: left;
width: 95px;}

 a{ color:tomato;  
    display: inline-block;  
    width: 100px;  
    text-align: center;  
    text-decoration: none;  
    line-height: 40px;}

main {
    background-color: burlywood;
    margin: auto;
    width:900px;
    height: 180px;
margin-left: 30px;}
    
#imagen{
    float: right;
    margin:10px; }
    
#texto{
    margin: 20px;
   float: left;}

aside {
width: 900px;
height: 370px;
margin-left: 30px;}
   
#materiasaprobadas {
    background-color: darksalmon;
    margin-top: 10px;
    height: 357px;
    float: left;
    width: 410px;
    padding-left: 20px;
float: left;}
#curso{
    background-color:lightsalmon;
    margin-top:7px;
    height: 337px;
    float: right;
    width: 400px;
    margin-left: 50px;
    padding-left: 20px;
    padding-top: 20px; 
float: left;} 

footer {
    background-color: darkseagreen;
    clear: both;
  height: 70px;
    width: 900px;
    margin-left: 30px;
text-align: center;}