#principale {
  width: auto;
}

header {
  width: auto;
  background-position: right center;
  height: 150px;
  background-size: cover;
}

nav {
  width: auto;
}

#content, aside {
  width: auto;
  float: none;
}

footer {
  width: auto;
}

aside h2 {
  text-align: left;
  background-position: left;
  padding-left: 14px;
  padding-bottom: 6px;
}