Ello nights ...
So, one thought I've had for Ello is to create a "night mode" style -- darker and/or muted colors.
Turns out that a fast path to that is using the CSS
filter: invert(100%); CSS filter (generally through vendor extensions, so:
-webkit-filter: invert(100%);, etc., for -moz, -ms, -o, etc.
Applying that to the body element inverts the color values of everything. Which ... isn't quite what you want -- it also hits images, background images, etc., which then have to be un-inverted. I did this in some cases but missed some of the sidebar avatars (see below). The Ello icon itself remains inverted.
Still, this gallery gives a general idea of what a naive approach would show (I've fixed most but not all of the inversions). It also highlights the fact that low-contrast light text on white backgrounds is a lot easier to distinguish than low-contrast dark text on dark backgrounds.
Which explains one of the reasons astronomers frequently work with photographic negatives: it's easier to spot the interesting stuff (light objects show as dark, on a white-background field). Not to mention cost (large-scale photo plates aren't cheap) and loss of clarity in generation transfer.