Gmail's dark mode goes missing, forcing our eyes to endure unbearable whiteness

Not everyone loves the "dark mode" trend that saw most popular apps get a white-on-black color scheme, but I'm a lifelong fan. It's good for your phone's battery (if you have an OLED screen), it's easier on the eyes, and it's just plain cooler to look at. 

Imagine, then, my surprise when I opened Gmail on my phone this...