Your design is difficult for people with non-typical color vision. Your indicators for available/taken need to have at least two different differentiators - eit

Your design is difficult for people with non-typical color vision. Your indicators for available/taken need to have at least two different differentiators - either a symbol+color, symbol+text, or color+text. For (even partially) color-blind people, solely using color doesn't have as strong of a meaning. In this case, it's not that I can't tell the colors apart - I can - but I can't immediately infer what the colors mean. The way I interact with colors is that they just don't have as strong of an implicit meaning as it seems they do for "normal" color vision people (probably because my color perception betrayed me too many times for me to develop a trust/dependency over the years). You can infer the available/not from the pop-out link, but that's disconnected from the status color icon, which makes it less intuitively connected. The color as distinguishing factor also has a cultural aspect - I think you're using stoplight colors, which are probably fairly safe, but it definitely doesn't hurt to help out people from a wide range of backgrounds / capabilities by adding another factor to distinguish.