While I love the step up to the platform, I agree - the stone and wood look odd together. What about some sort of wooden archway and wooden stairs - I know that sounds obvious... also there are parts of the outer inventory window overlapping the inner one with the character in it... I also know from expirence that it is nearly impossible to allign the derned things so that they mesh perfectly though after some fiddling I did figure out a way which involved these steps:
In the outer one make the entire inventory window including the inner part - all as one image.
Be sure that the old inventory is still the bottom layer.
copy and paste the old inner one into the new one, allign it with the old outer inventory window, then make all layers invisible and inactive except the old inner window, then use a select by color or contigious region to select the transparant area around it, then select inverted so that an area of the same size and location as the smaller inner window is selected - then reactivate the new inventory background, crop the image based on the selection, save it ias the inner png file, then undo those changes, and instead of cropping to that area, delete all content in that selected area. Then you have two parts that mesh perfectly.