span.check {color: red; background: red;}

div.menu {
  position: absolute; left: 0; top: 1em;
  width: 8em; height: 10em;
  margin: 0; padding: 0;
  z-index: 3;
}

body > div.menu {position: fixed;}
div.main div.menuwrap {
  width: 7em; height: 10em; margin: 0.5em 1em; float: left;
}
div.menu ul {
  margin: 0; padding: 0;
}
div.menu ul li {
  border: solid 4px #44d;
  list-style-type: none;
  margin: 0; padding: 3px;
  background-color: #bb0;
  height: 1em;
}
div.menu ul ul {
  position: absolute;
  left: 7em; width: 7em;
  visibility: hidden;
}
div.menu ul ul li {
  border: 1px solid black;
  background-color: white;
}
div.main {
  height: 99%; overflow: auto;
}