Would like some feedback on the code for my Wikipedia viewer

everything works the way i want it to, but since i’m just a few weeks into learning web dev, i would really appreciate some experienced eyes on this to see if i’m implementing any bad habits. i’d rather nip them in the bud now than have to deal with them once they’re ingrained into my workflow

thanks in advance!

project link - http://codepen.io/montycantsin/pen/NjvwXG