[Rezza Mohammad]

Hello Dan, I was tried your Expression, but something is missing at Mode like they not switching and only stay at the light layer, but On/Off and Opacity Slider it was working perfectly like what I want.

However, I made a bit changes to my Expression below.

//For Light Layer
Mode = thisComp.layer("Mode").effect("Mode")("Checkbox").value;
IsDark = thisLayer.name;
IsLight = 
OnOff = thisComp.layer("Mode").effect("OnOff (Light_Element 1)")("Checkbox").value;
Opacity = thisComp.layer("Mode").effect("Opacity")("Slider");
IsActive = (Mode && IsDark ) || (! Mode && IsLight );
if (IsActive && ! OnOff){
 Opacity;
}else{
 0;
}

//For Dark Layer
Mode = thisComp.layer("Mode").effect("Mode")("Checkbox").value;
IsLight = thisLayer.name;
IsDark = 
OnOff = thisComp.layer("Mode").effect("OnOff (Dark_Element 1)")("Checkbox").value;
Opacity = thisComp.layer("Mode").effect("Opacity")("Slider");
IsActive = (Mode && IsDark ) || (! Mode && IsLight );
if (IsActive && ! OnOff){
 Opacity;
}else{
 0;
}

Here is preview.
https://www.mevue.com/v/4bbzs8t7829

Again. Thanks a lot for your help guys, I really appreciate it!

And thank you so much, Dan!

You saved me, you are my favorite 🙂

[Rezza Mohammad]

Sorry I missed the details.

Opacity is zero when the second checkbox is checked – even if the first checkbox is checked or unchecked.