To clarify, it is not the total number of words but rather the number of unique words considered. Imho a million of unique words is okay. A bigger concern for me would be that words on Wikipedia can be overly specific.
For this metric, Wikipedia might not be a representative dataset. Wikipedia uses many technical terms and composite words which tend to be longer than words that are more common in an everyday dialect.
Oh, somehow I missed the theme setting. I tried both firefox and chromium and got the light theme by default despite having my system/browser settings set to prefer a dark theme.
There were some comments on Reddit suggesting that cutting the dataset at 15 and removing 40% of words was not the best move. I have locally built a version with the limit set to 30.