.expression_popup {
  position:   absolute;
  background: #f0f0f0;
  padding: 3px;
  border: 1px solid black;
  border-radius: 4px;
  box-shadow: 1px 1px 5px 0 #303030;
  width: 450px;
  text-align: left;
  display: none;
  white-space: normal;
}
.expression_btn {
  white-space: nowrap;
  border: 1px solid white;
  text-align: center;
  vertical-align: bottom;
  
}
.expression_btn_highlight {
  border: 1px solid black;
}
.expression_text_box {
  width: 600px;
}
.expression_long_text_box {
  width: 700px;
}