The feeling of opening up Twitter and noticing that something is of is probably not a new one, but it is usually not related to the color scheme of the site. Some users (and The edge employees) now see that Twitter’s dark mode on the desktop has gotten darker, or worse, changed to light mode.
Twitter tells The Verge that the change from blue to black was intentional – it’s part of an update to get the Twitter site to respond to the light and dark modes of your operating system. Of course, if you miss the dark blue, you can bring it back by going to Twitter̵
However, if Twitter switched from dark mode to light, the company says it should not happen. It was caused by an error, and could have happened to you if you had Twitter set to Dim or Lights Out mode, but had the operating system in light mode. Go to the display settings to change it back, if you want.
While you are there, you can also choose an accent color, if you are tired of blue.