@namespace url(http://www.w3.org/1999/xhtml);

@-moz-document domain("www.itmedia.co.jp") {
.header,
.rc,
.footer,
#txtad,
#btnlist,
.bookmarks,
.adsense {
  display: none !important;
}
.l600 {
  margin: 0px !important;
}
}