Decades of research, then another decade in the 90s of everyone rediscovering for themselves how bad light fonts are on dark backgrounds when everyone made their own website. It was a shitshow, and generally plain old dark text on light backgrounds became the norm again. So called dark mode is just another fashion trend that's been available forever in custom themes, and it's just making a temporary comeback. Likely so marketing can come up with 'light mode' in a few years and say they're doing something cutting edge.

So they're recording whispers?

I think these kinds of notes in books were not uncommon at all back in the day. My great grandfather wrote in several of the big books that were handed down "This book belongs to ____. If you take it, and don't give it back, then you are no darn good." We always kinda laughed at that in our family, but lots of people took that a little more seriously then.

Wuala has a java based client that links to local file folders when it's running. It's encrypted on your computer before being stored over the network, so only you can decrypt everything. And if needed you can access things through their website too. Lots of sharing options also if you wanted to. It's worth checking out. Wuala.com