Hello, all! Please forgive me for being nooby, I am new to the pixel art world.

I am using a 5-color palette. I am practicing on structure/texture drawing on rocks.

I chose the light source to be the top right.
But while doing this...I am confused on certain things.

Especially with shading/highlight and depth.

Things are supposed to be lighter in the distance, right? Because as the objects are farther, they get harder to see, and less detailed.

Well as I put the highlights on my rocks, I think about the rocks in the distance...and if I choose the lighter colors for it... they kind of blend in with the rocks that are closer to the viewer (me lol)

I don't know what to do. Should I work on my color palette?

Or should the rocks in the distance have some sort of contouring lines to let the viewer know that they are behind the rocks that are in front?

Thank, you all in advance! I hope everyone is having as much fun with pixel art as I am (maybe even more)!