I don't understand how to reproduce the issue. I should be clicking on a link to make it active, correct? None of the links seem to work, so I'm missing something.
I can view your page to see the CSS. No need to include that.
I need steps to reproduce the issue with a description of what you want to happen. I was thinking the steps were to click on a link and that the link should remain active, but when I click the links it takes me to another page and there is no "active" class being added in the html.
The CSS won't ever work if the class isn't added in the first place.