As I wrote this, I didn't read that it was about light...
#fca4a4 sweet pink, kinda like salmon but more red on the Hue slider. I use it as my brand color! Even though I don't really use it much.
Obsidian is wonderful. I have folders with daily or weekly notes (and could do monthly or yearly too) similar to what you said. There are so many other features that I could use but haven't yet, because I got it working exactly how I need right now.
One example I use besides journaling is taking notes on YouTube videos. For example, with interviews of YouTubers who give a lot of advice. I can put them all in a folder and/or apply a tag to find them in the same place later.
Fennec F-Droid