Perhaps it would be better if instead of showing all 3 color key legends all the time, we could show only the applicable color keys under the Chime plug-in. For this, a single push-button would need to apply a script to Chime and simultaneously change the color key legend. This cannot be done in ordinary HTML, but is straightforward in Javascript. Here is an example.

Would we like the Heme + protein button to restore the protein in whatever rendering was in use when the Heme only button was pushed? This means that the previous state has to be remembered, something not possible in ordinary HTML but easy in Javascript. Here is an example.

The above are merely two examples of many possibilities enabled by Javascript.