body {
 width: 99%;
 margin: 2px auto;
 font-family: Arial, "MS Trebuchet", sans-serif;
 text-align: center;
}
header, footer, section, aside, nav, article { display: block; }
 
header#page_header {
 width: 100%;
 margin: 4px auto;
 border: 2px solid blue;
}
header#page_header nav ul {
 list-style: none;
 margin: 0;
 padding: 0;
}
#page_header nav ul li {
 display:inline;
 margin: 0 20px 0 0;
 padding: 1px;
}
section#posts {
 float: right;
 width: 62%;
 background-color: #f1f2fe;
 border: 1px solid yellow;
}
section#posts header#posts_header {
 background-color: #abcdef;
 border: 1px solid green;
}
article.post {
 margin:10px;
 background-color: yellow;
 text-align: left;
}
article.post aside {
 float: right;
 margin-top: -58px;
 width: 250px;
 height: 120px;
 background-color: #fefefe;
}
article.post p { clear: right;}
section#sidebar {
 float: left;
 width: 35%;
 background-color: #d7d8fe;
 border: 1px solid green;
 padding:5px;
}
section#sidebar nav ul {
 margin: 3px auto;
 text-align: left;
 padding: 0 0 0 15;
}
section#sidebar aside {
 width: 160px;
 height: 250px;
 margin: 10px auto;
 background-color: #fefefe;
}
footer#page_footer {
 clear: both;
 width: 100%;
 margin: 4px auto;
 border: 2px solid blue;
}