This is my link https://codepen.io/SONGA68/pen/VwWNxrZ, thank you in advance
Mostly correct!
You forgot to do following task on the last paragraph:
Semantically associate machine-readable dates with the dates in the text.
Hint: You did it in the “Marking up a letter” assessment 
If you like, you can update the code and I will have a second look at it.
Michael