.content-node .math_environment_reference {
  background: rgba(145, 187, 4, 0.15);
  border-bottom: 1px solid rgba(145, 187, 4, 0.8);
  color: #495A11;
  cursor: pointer;
}

.content-node .math_environment_reference:hover { 
  background-color: rgba(145, 187, 4, 0.35);
}

.content-node .math_environment_reference.active {
  background: rgba(145, 187, 4, 0.7);
}