So that's what the Luxo lamp in my Chrome toolbar is for! (I have the Evernote extension installed in Chrome, and it includes Clearly as well.)
It's funny, I've hardly ever used that thing. Like a dummy I forget it's there, and instead I go in and hack the CSS (mostly removing styles) and then post sarcastic comments about it.
But you're right, I just clicked the Luxo lamp and the whole page became perfectly readable.
And then I dragged the Luxo lamp over to the left where my most-used extensions are, so I'll remember it next time.