body {
  padding: 20px;
  background-color: #F4F4F4;
}

h2 {
  font-weight: bold;
}

#flmngr-panel {
  box-sizing: border-box;
  position: relative;
  overflow: hidden;
  resize: both;
  padding: 20px;
  background: #CCC;
}

#flmngr-panel:before {
  content: "Loading...";
  position: absolute;
  top: 50%;
  left: calc(50% - 50px);
  width: 100px;
  text-align: center;
}