Find accessible colours for the web (source)

I finally got around to getting my website back up and running. Years ago now I started the process of re-building my website (yet again), this time as a link blog. I finally finished getting the machinery working and old content ported over, then of course had to bikeshed the UI for a few days. Anyway one thing I wanted was different colours for the different types of entries. But eyeballing them was leading to poor choices that were hard to read, so I built this tool to make it easier to find colours that still meet contrast requirements for readability on the web.