I was browsing through the resource packs on Modrinth when I came across this one:
https://modrinth.com/resourcepack/enhanced-travelers-backpack-gui

And I thought it would be nice to have a similar or at least improved interface to the one we have today.
Traveler's Backpack is a great mod, however the interface is quite flat, too simple for what the mod offers, in my opinion it should be tweaked.

I want backpack gui to fit vanilla guis and I'm open to any suggestions how to improve backpack gui in vanilla manners.

Understandable, then I can only recommend 2 things that don't change the "Vanilla" style of the GUI:

• Water and lava rework: the water and lava textures are not like the vanilla ones. In my opinion they should be rework.

• Add the name to the GUI: Each Minecraft gui if opened is also indicated by a name, this is missing in your mod, it would be enough to add "Backpack" or "Traveler's backpack". This i what i mean:

How is water and lava not the same like in vanilla? I use the same textures

I mean I use textures that minecraft provides for all fluids

I looked at the GUI again, actually you are right, sorry 😅😂

Just watch the second suggestion