Sorry for dredging up an old thread, but did anyone ever find a fix for this? It appears as though a single line of the apps background colour creeps through sometimes on the bottom line of the screen (ie, foreground elements don't fit exactly 100% of the card).
It can be hard to see, but if an app has a default of a white or light card and then a dark list or some other widget is on it, it can show through. I'm trying to remove the issue from Project Macaw but aren't having much luck.
Might be as simple as CSS fixes but not sure. Thinking maybe calling 100% on background-size might not in fact scale to 800 pixels on the pre, but rather 799. No evidence of this, just an idea.