section

Style element:

<style>
body {
  margin:0;
  padding:0;
  font-family:'Arial', sans-serif;
}

header, nav, article,
section, aside, footer {
  margin:10px;
  border:solid 10px;
}

header  { border-color:#fcc; }
nav     { border-color:#cfc; }
article { border-color:#ccf; }
section { border-color:#ff9; }
aside   { border-color:#f9f; }
footer  { border-color:#9ff; }
<style>