Understanding your Advent Calendar
<spoiler=Example Image>
This is what you are seeing in the example above:
Day 1: Earlier content, you've already opened the box
Day 2: Earlier content, you've not opened the box
Day 3: Earlier content, you've not opened the box
Day 4: It's day 4, and you've seen it (If you haven't, it will look like 2 & 3, except with the number 4)
Recap:
Anything you haven't seen will have a 'lit' box. Anything you have seen will be unlit, and if it's today's box, the 'doors' will be open to show the item below it.
Hope this helps clear up any confusion.