Methinks you're looking for
"sudo brightnessctl set 10%-" to dim incrementaly or use + to make brighter.
Or:
"sudo systemctl [suspend|sleep|hybrid-sleep|hibernate]" take your pick of the last command-option to put your system to sleep.
Otherwise there's always standard "i3lock" to lock your screen.
Never saw a cairo dimmer .....there was one on e17. A slider on the "shelf" bottom right in the screen.
LOL
My new 32 Inch ViewSonic has it's PoweOff Button in the back and is difficult / long to turn off :P: To avoid having to wrap my hand under or right to the screen to simply turn it off, i prefer a keyboard shortcut LOL If I was able to i3lock + turn it off in one command it would be cool...
It is part of the "xset" options.
From "xset --help" :
To control Energy Star (DPMS) features:
-dpms Energy Star features off
+dpms Energy Star features on
dpms [standby [suspend [off]]]
force standby
force suspend
force off
force on
(also implicitly enables DPMS features)
a timeout value of zero disables the mode
If I use -dpms on e16, screen blanking takes noticably longer to set in.
You can set it to whatever colour you want, actually. I set it to white so as not to be confused by screen blanking ...... which doesn't require password, normally.