Table borders not showing in Andressen theme

I hope this helps.
This table has no borders and also strange large font in the header for the two right columns.
View output here: https://iagtm.pressbooks.com/chapter/story-introducing-the-pantheon/

Related Greek / Roman god / other

English vocabulary and definition

Relationship between vocabulary and story

Gaia "mother earth"
X prefix geo-
terrestrial
the Gigantes gigantic
X giant
X titanic
Chronos chronological
X chronicle (noun / verb)
X synchronize
saturnine
iris (meaning 1)
iris (meaning 2)
Amaltheia cornucopia
X copious
Zeus' shield under the aegis of
martial
Vulcan volcano
X to vulcanize
aphrodisiac
Venus venereal
X venerate / veneration
X venom
Hermes hermetic
X mercurial
X merchant
X merchandise
X commerce
erotic
the Muses to amuse
X to muse
X museum
X music
X amusement
X to be (someone's) muse
Mnemosyne mnemonic
X memo
X remember
X memory
chaos
Phobos phobia
I don't know how to get this to show the code!