changing the color of visted hyperlinks in a text block

Hi Susan,

Thank you for sharing your voice with us!

While there isn't a way to show a hyperlink as visited, another option is to use a Text Box with a Change State trigger and Open URL trigger. You can also apply a Hover state so it is clear that the text is clickable. Here is an idea of what that setup would look like: 

Here is an idea of what the triggers would be:

Here is how it would look in a Published Output: 

I will be sure to update our team with your request. If we add this feature to Storyline, we'll let you know!