%fadable-control {
  visibility: hidden;
  &.factlink-control-visible {
    visibility: visible;
  }
}

// This is done because of transitions crashes on iOS devices.
// For now we're disabling transitions on devices smaller than 1025 pixels
// Most PC have bigger screens so, this works perfect for PC's
@media only screen and (min-device-width: 1025px) {
  %fadable-control {
    transition: opacity $control_visibility_transition_time,
    visibility 0 $control_visibility_transition_time;
    opacity: 0;

    &.factlink-control-visible {
      opacity: 1;
      transition: opacity $control_visibility_transition_time,
      visibility 0 0;
    }
  }
}

%fadable-control {
  visibility: hidden;
  &.factlink-control-visible {
    visibility: visible;
  }
}

// This is done because of transitions crashes on iOS devices.
// For now we're disabling transitions on devices smaller than 1025 pixels
// Most PC have bigger screens so, this works perfect for PC's
@media only screen and (min-device-width: 1025px) {
  %fadable-control {
    transition: opacity $control_visibility_transition_time,
    visibility 0s $control_visibility_transition_time;
    //note the time unit is REQUIRED even for 0s!  FF won't accept 0.
    opacity: 0;

    &.factlink-control-visible {
      opacity: 1;
      transition: opacity $control_visibility_transition_time,
      visibility 0s 0s;
    }
  }
}

Fix firefox fade: transition requires 0s
Fix firefox fade: transition requires 0s
