Just click on the box that you wish to get the hex code from.

FF0000 00FF00 0000FF FFFF00 FF00FF 00FFFF 7F0000 007F00 00007F 7F7F00 7F007F 007F7F FF7F00 FF007F 7FFF00 00FF7F 7F00FF 007FFF 7FFFFF FF7FFF FFFF7F FF7F7F 7FFF7F 7F7FFF

To use the code in html, all you have to do is instead of using a {color="red"} type {color="#(then the code that it tells you when you click)"}.