Hey! im having issues trying to set a streamlit theme, when i make a file at .streamlit/config.toml and enter this:
[theme]
primaryColor="#16F1AC"
backgroundColor="#f0f0f5"
secondaryBackgroundColor="#e0e0ef"
textColor="#262730"
font=“sans serif”
nothing changes(one time i did get an error, “theme.primaryColor” is not defined.), plus when i go to the menu and then to settings i cannot see a theming option, do i need to enable something somewhere?
In your code of config.toml file, you have wrong type of quotes in the last line (sans serif). I have changed them to normal(“”) and was able to reproduce your theme.
ah, thank you!
i still get this error AssertionError: Key “theme.primaryColor” is not defined. I think it is something to do with the actual setup i have, am i meant to have lots of lines in my config.toml(ie. other sections) too?
Hi @Epicfaze44, could you check if you’re running Streamlit version 0.79? That error gets thrown when you try to define a config option that doesn’t exist, and I’m not sure how that could be happening aside from the case where you’re not upgraded to the most recent version.
im on 0.78 
haha i guess i will need to upgrade
Hi, I upgraded to 0.79 but the error stays the same
AssertionError: Key “theme.primaryColor” is not defined.
My config is
[server]
port = 4200
[browser]
serverAddress = "localhost"
[theme]
primaryColor="#3390FF"
backgroundColor="#FFFFFF"
secondaryBackgroundColor="#F0F2F6"
textColor="#262730"
font="sans serif"
(browser and server params work as expected)
Hello I have almost the same problem.
It is possible to set theme with st.set_option?
@Alea4jacta6est: I’d double-check that something weird isn’t happening with your installation / virtual env since unfortunately I can’t think of a reason why you’d get that error while on 0.79. Does running streamlit config show include a [theme] section in its output? It would also be worth checking that streamlit version verifies that the installation is version 0.79.
@LucianoSiqueira: it’s not possible to use st.set_option to set the theme. Please see the API docs for a list of options that are configurable using that API.
strange but streamlit version shows 0.79 however [theme] is absent. Just rebooting the system helped, may be cache problem…
Huh, that is quite strange. Hopefully this was indeed some sort of caching issue and the reboot ends up being a permanent fix.
In case this happens to reappear, please feel free to file an issue in GitHub and tag me in it as we’ll certainly want to investigate further.
I do have the same issue! I am using v0.79, I initialized the config.toml file streamlit config show > /.streamlit/config.toml, it works in the localhost. But same key-error in the share oven 
Had the same issue, theme options didn’t show in settings via browser, or showed the same error when .streamlit/config.toml file present.
Computer reboot, then pip install watchdog solved it.
nope.