Suggestion: all available color schemes for memory usage are low contrast -- change that.

[user23108947023948]

I think the memory usage meter in htop is hard to read no matter which color scheme I pick. I think that the bars on the left indicating actual usage should be a strong color and the remainder (indicating unused memory) should be very faint, almost matching the background color. That would make it a lot easier and faster for the user to tell at a glance without having to stare carefully at the screen to determine where the bars change colors.