* { margin:0;
     padding:0;}

header { 
   background: #f3f4f4; /* Para Internet Explorer */
   background: rgba(209, 209, 209, 0.7);  /* Para los navegadores que soportan RGBA */
    width: 80%;
    height: 75px;
    align-content: left;
    margin-left: 10%;
    -moz-border-radius-bottomright: 10px;
    -moz-border-radius-bottomleft: 10px;
    -webkit-border-bottom-right-radius: 10px;
    -webkit-border-bottom-left-radius: 10px;
    text-decoration: none;
    clear: both;
}

nav ul li {
    display: inline-block;
    padding: 8px;
    background: #f3f4f4; /* Para Internet Explorer */
    background: rgba(209, 209, 209, 0.4);  /* Para los navegadores que soportan RGBA */
    border: 1em;
    border-color: #000;
    text-decoration: none;
    margin: 2px;
    color: black;
    height: 10%;
}

nav a {
    display: inline-block;
    background: #f3f4f4; /* Para Internet Explorer */
    background: rgba(209, 209, 209, 0.7);  /* Para los navegadores que soportan RGBA */
    text-decoration: none;
    color: black;
}

nav a:hover {
    display: inline-block;
    padding: 8px;
    background: #f3f4f4; /* Para Internet Explorer */
    background: rgba(0, 137, 253, 0.9);  /* Para los navegadores que soportan RGBA */
    border: 1em;
    border-color: #000;
    text-decoration: none;
    margin: 2px;
    color: black;
    -webkit-transition: 1s;
}

h1 { 
    font-size: 15;
    font-family: url(https://www.google.com/fonts#QuickUsePlace:quickUse/Family:Lobster);
}

body { 
    background: url(IMAGENES/background2-1024x640.jpg) no-repeat fixed center;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}

article {
    float:left;
    border: 2px solid red;
    margin-top: 60px;
    height: 400px;
    width: 59%;
    }

aside { 
    background: #f3f4f4; /* Para Internet Explorer */
    background: rgba(37, 188, 255, 0.7);  /* Para los navegadores que soportan RGBA */
    float: left; 
    width: 20%;
    margin-left: 10%;
    padding: 20px;
    margin: 5px;
    margin-left: 10%;
    margin-top: 60px;
}


footer {
  padding-bottom: 3em;
  padding-top: 1em;
  padding-left: 1em;
  padding-right: 1em;
  margin-right: 1em;
    -moz-border-radius-topright: 10px;
    -moz-border-radius-topleft: 10px;
    -webkit-border-top-right-radius: 10px;
    -webkit-border-top-left-radius: 10px;
   background: #f3f4f4; /* Para Internet Explorer */
   background: rgba(209, 209, 209, 0.7);  /* Para los navegadores que soportan RGBA */
    background-position: bottom;
    float: bottom; 
    width: 80%;
    height: 20%;
    align-content: left;
    margin-left: 10%;
  clear:both;
    font-size: 7;
}