I noticed that Stack Overflow was looking somewhat different today but I couldn't figure out what was going on. Until I compared an already open tab to a newly opened tab.
Did the top level menu font change from bold to non-bold or are my eyes playing tricks on me?
Already open menu:
New window menu:
I am seeing the new font in Chrome, Firefox. I see the change on Stack Overflow as well as on Meta. Is this a new permanent change?