Backend showing up without style: Just a big page with lots of links

I haven’t worked on this site for a while ( https://www.greenhomechronicle ) but when I signed in, it took me to a a backend hompage that’s devoid of any style. It’s showing up as a series of links showing up as a sans serif blue type all the way down — one link on each line. There are some WP icons (chain for links, etc.), and check boxes, as well but not that much else. Anyone have any idea of what’s happening there? I’m wondering if it’s a plugin that I failed to update? If so, how can I fix that now?