I figured out how to get lines - but it's pretty clunky. You need to add the following to each <td> element. As in, you need to go into the html and find each <td> and add this to the very end
style="border:1px solid black;"
<td style="border:1px solid black;">
It would be lovely if there was an easier way. I also need to have some tables entirely white (rather than striped). The code isn't working for that. Any ideas?
I need it for table 2 on this page: https://bio.libretexts.org/Bookshelves/Human_Biology/Book%3A_Human_Biology_(Wakim_and_Grewal)/08%3A_Inheritance/8.5%3A_Complex_Inheritance
The band in the middle makes the pictures look weird. White would look better. Not a bit deal if it's not possible.