Hmm. Generally, I’m a fan of white text on a dark background, but something isn’t resonating for me here.
Apart from what may just be unfamiliarity, there are a few things that should be tweaked:
Title text/icons are now medium-gray on slightly-darker-gray. Maybe a bit more contrast?:
And while the areas where the light blue is thick “pop” like you say, where they’re thin, they take a lot of effort to read:
(See the “cancel” and “You can now select” etc. in that image)
ETA: I think part of what’s bothering me is that, while the subtle blue highlighting of a post appearing looks awesome against a white background, it just doesn’t look quite right as a dark-gray-blue fading to dark-gray.