Steam hasn't murdered Windows 7 in cold blood... yet. it's (at the time of making this article) the 3rd day of the new year and it's still working fine for me on Windows 7 - 8.1.
i even did a fresh install in a vm to prove it still works. here's the Steam installer i downloaded directly from steampowered.com.
and here's the installer working as usual.
there's the shitty new electron-based login screen. it sucks but works as it should lol
and wow, look at that, babyducks rejoice! wangblow 7 can still run your vidyas on Steam.
keep in mind though that the last update for Steam was in December. the next update will probably break support for Windows 7-8.1. just in case Steam pushes this update to legacy Windows users to kick them out of the Steam ecosystem or something i'd recommend disabling updates using this guide. it's also in general really helpful for the inevitable future when older versions of the Steam client start to break,