I believe there are several problems. First of all, I believe you want to write the display:none CSS logic this way:

.inner-card.active{
    display: none;
} 

This means that the inner card will be hidden if it also has the active class.

Secondly, I believe you need to rewrite the script this way:

 $(document).ready( function(){
     $('.card').click( function() {
         $(this).find(".inner-card").toggleClass('active');
     });
 });

When you use the toggleClass you need to use just the name of the class, not the selector (-> no dot). Also, from the CSS, it looks like you need to find the inner card element first.

Fiddle link