This has been around for a couple weeks, but I thought I’d mention it here. It’s a page meant to let you inspect colors and fonts inside a functioning browser. I made it for some graphic designers I work with, who were disappointed that their Photoshop-chosen colors did not translate consistently to the web. This allows them, and you, to test out font sizes, faces, and color/background color combinations for visibility.
At some point I will add an overlay that allows you to (roughly) simulate a PC screen on a Macintosh, and vice versa.
Update: I’ve added the Mac/PC simulators. They’re very crude, but they should give you a rough idea of the color transformation between the OS’s.