#trace, #debug {
  position: fixed;
  width: 40px;
  height: 40px;
  padding: 10px;
  overflow: hidden;
  z-index: 10000;
  right: 0;
  bottom: 0;
}
#trace {
  right: 0;
  bottom: 0;
  background: red;
}
#debug {
  right: 0;
  bottom: 40px;
  background: blue;
}
#trace:hover, #debug:hover {
  right: 0;
  bottom: 0;  
  width: 100%;
  height: 100%;
  overflow: auto;
  background: #fff;
  
}