What is the difference between journald.conf and system.conf

I know that systemd is a mechanism of service management.

But I don't know why there are two config files: /etc/systemd/journald.conf and /etc/systemd/system.conf.

For example, in the system.conf, I see there is a line: LogLevel=info, and in the journald.conf, there are some lines:

#MaxLevelStore=debug
#MaxLevelSyslog=debug
#MaxLevelKMsg=notice
#MaxLevelConsole=info
#MaxLevelWall=emerg

They look very similar.

What's the difference between both of them?