Audacity questions

I have a few questions about Audacity. I know these questions might seem elementary to some. But sometimes, we just don't know what we don't know.

In the example I provided:

1. Why are the long lines light green and then dark green?

2. What do the separate green bar slices mean?

3. Occasionally, the separate green bar slices are red, yet the overall metering doesn't extend into the right border, and the graphic images below (not shown in png) remain in the borders. What does this mean?

4. What do the separate blue slices mean?


Thanks.

A quick description of these bars from left to right. Firstly, the light green section represents the current amplitude level. The dark green portion represents the recent highest amplitude level, and the green line represents the peak amplitude in a given period of time. All of these will move dynamically with amplitude level and time. The blue lines represent the maximum permissable amplitude level. Should the amplitude exceed this level, the bar will turn red.

Thanks, all, for this information--and, I hope, for not laughing too loudly at my questions. I've been using Audacity for years and never quite understood much of what I was looking at and thus what was going on.