What I did: My default system wide accent color on macOS is blue
What happened: The accent color is orange
What I expected: The accent color should be blue
Things that might be helpful to know (Agenda version, OS and model, etc):
Agenda: 9.3.2
macOS: 10.15.4
Whenever i change my system wide accent color to a different color than blue, agenda is using the new color. When I go back to blue, the system accent color is blue but agenda is using orange.
Clearly the devs have something against blue…
We have nothing against blue, but rather have a preference for Agenda orange 
Joking aside, the rationale and a way to switch to blue is given here:
Thanks! That works.
Please note that the default color combination has a contrast of 1.77, which is far to low for many, many people. To meet accessibility standards, a 4.5 contrast ratio is the minimum for text, and 3 is a minimum for other graphical elements.
I understand that you want to use your color, but it might be good to provide higher contrast colors for the users who need it (and not hide it behind a terminal command).
This is only true for the blue accent colour, if you choose any of the other system highlight colours it will be used instead of the orange. We will have a look if we can use the default as well if you have the high contrast setting enabled.
I’m not using the system high contrast setting (I don’t need it) and my “Accent Color” is set to the app default, which in Agenda is just too little contrast. I would not suggest this if it was not far below the usual contrast thresholds.
I hear you, but we’ll stick with the current setup for Agenda I’m afraid, in these cases the hidden preference is the way to go for now.
It’s unfortunate to chose style over an option for usability in that case.
You are asking us to completely change the appearance of our app, which as important part of our branding, and the look and feel of the app. We offer alternatives for people who have trouble with it.
The accent color is not used for general text, just for some controls and highlights. Even if you don’t find it ideal, it is not used widely enough to cause serious issues. It is not as though all the text is yellow.
I have not asked for that. I asked for similar ease of customization that is already possible on iOS devices and through the system settings.
Thanks anyway for the consideration, I have understood.
Perhaps, exposing that setting in the MacOS version’s preferences to make it more easily discoverable would be a good solution. That way people who want this changed wouldn’t need to search the forums first and then have to venture into the Terminal.
Yes, but that ties into another difficult topic, which is, we are very critical as to what we expose as a preference or not. It’s true that it’s easy to add, but it’s also easy to turn the preferences (and the app) into one big bloated Christmas tree of options and features (Microsoft Word style). So far we don’t feel this is a frequent enough issue for it to justify the checkbox.
Can’t get this to work, maybe it’s Big Sur?
Default setting on Mac is blue but like orange on Agenda. Didn’t work following step above and replaced with:
defaults write ~/Library/Containers/com.momenta.agenda.macos/Data/Library/Preferences/com.momenta.agenda.macos useSystemOrangeAccent -bool YES
Still displaying blue.
Tried both defaults write and defaults delete in variation, even changed system colour to green, defaults write to blue but Agenda still showing green. Agenda always follow system colour. MacOS is Big Sur.
I’m using Agenda 13.1.1 (195) (Mac App Store) on macOS Big Sur 11.5.1. Agenda seems to respect my accent color preference in System Preferences. When I set the accent color to blue, Agenda turns blue. I never tinkered the app with Terminal to make this happen. (I never knew that you could change the accent color in Agenda for Mac like in the iOS apps. I only discovered it by accident when I changed my system accent color from multicolor to blue.)