*   {margin: 0;}
body    {
    font-family: sans-serif;
    background: #f8f8ff; }
header {
    background-color: #1f242a;
    color: #fafafa;}
header img  {
    float: left;}
header p  {
    font-family: 'Open Sans', sans-serif;
    font-size: 30px;
    padding: 170px 0 0 250px;}
header img  {
    border: 10px solid #fff;}

nav {
    font-family: 'Open Sans', sans-serif;
    font-weight: 400;
    font-style: italic;
    background-color: #1EA6FF;
    text-transform: lowercase;
    height: 60px;
    clear: both;}
nav ul  {
    list-style: none;
    padding: 0;
    text-align: right;
    float: right;}
nav ul li   {
    float: left;
    margin: 20px;}
nav a   {
    color: #fafafa;
    text-decoration: none;}
nav a:hover {
    color: #000}
#materias   {
    background-color: #b54249;
    width: 60%;
    height: 500px;
    display: inline-block;
    color: #fafafa;
    margin: 20px
    }
h1  {
    font-family: 'Open Sans', sans-serif;
    font-weight: 800;
    font-size: 20px;
    margin-top: 50px;
    margin-bottom: 10px;
    text-align: center;}
h2  {
    font-family: 'Open Sans', sans-serif;
    font-weight: 600;
    font-size: 16px;
    margin-bottom: 5px;
    margin-left: 70px;
    color: #fafafa;}

section p {
    font-family: 'Open Sans', sans-serif;
    margin-left: 70px;
    margin-bottom: 20px;}
section ul li {
    font-family: 'Open Sans', sans-serif;
    margin-left: 70px;}
aside {
    float: right;
    width: 40%;
    height: 500px;
    background-color: #282c35;
    margin-right: 20px;
    margin-top: -520px;
    padding-left: 30px;}
aside h1    {font-size: 20px;
    color: #fafafa;
}
aside section  {
    width: 100%;
    }
aside p  {
    font-size: 14px;
    color: #fafafa;
    }
footer {
    font-family: 'Open Sans', sans-serif;
    color: #fafafa;
    background-color: #1EA6FF;
    clear: both;
    height: 160px;}
footer p {
    padding: 50px;
    text-align: center;}

 <!-- CARTA -->
header #carta {
    height: 300px;
    background-color: #1f242a;
    color: #fafafa;}
header h1    {
    font-size: 30px;
    margin-top: 0px;
    padding-top: 20px;}
#carta article p    {
    font-size: 20px;
    color: #fafafa;
    margin-top: -100px;
    margin-bottom: 50px;
    width: 800px;
    }
#carta-estructura   {padding: 50px;}
#carta-estructura p   {padding-top: 20px;}