something strange just happened to me.
closed my browser and when I opened a tab into the forums, it loaded with the dark theme and didn't provide the bar in the upper right to let me log in. I scrolled down to the bottom of the forum and saw something saying dark theme, clicked it and it gave me the option to change to light theme, which I did. BANG, the login option appeared above the FORUMS, WHAT'S NEW etc in the upper right. switched back to dark theme, it disappeared...back to light and it was there.
I'm logged in now though, under the light theme, which is what I have selected in my profile as default.
just thought I'd give a heads up in case something somewhere is misbehaving?