I just realized how important it is that cards not only have their number (9, 3, K, etc) printed in the top-left but also an appropriate number of symbols on the body of the card. My eyes seem to gloss over the cards and at first glance I failed to notice that I could start by stacking some of them instead of drawing 3 more.

I see the symbols are just unicode, so you could use some CSS absolute positioning to create the different arrangements.

Presuming you are the author who submitted it: What was experience like using Dart in this project? How do you think it would compare to using JavaScript to implement a similar game?