Error: "Uncaught Cannot tween a null target" when using the CssRule Plugin

[gimperdaniel]

Here's my code:

var connectors_tl = new TimelineMax({repeat:-1,onRepeat:change_position});

        var connector_before = CSSRulePlugin.getRule(".connector:before");
        var connector_after = CSSRulePlugin.getRule(".connector:after");

        connectors_tl.add(TweenMax.to(".connector",1,{opacity:1,repeat:1,repeatDelay:3, yoyo:true}));
        connectors_tl.add(TweenMax.to(connector_before,1,{opacity:1}));

I was basing my code on the example here:

 

 

I already have the before and after defined in my css with opacity:0;

 

What does the error mean?

See the Pen ibHAt by jamiejefferson (@jamiejefferson) on CodePen

[gimperdaniel]

Never mind. I figured it out. 

 

I had my css defined as 

#myID.connector:after{}

And I was trying to select just 

.connector:after{}

It looks like that the CSSRulePlugin selection must have the exact same selector structure.

 

So this works:

CSSRulePlugin.getRule("#myID.connector:after");