both the top and bottom screens are a collection of different sprites and resources from the game. I take (almost) everything from TSR (thanks to all the people who ripped the sprites I used for this theme! more detailed credits down below). The color palette of the buttons is based on the colors of the Japanese logo of the game.
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Credits:

Yoshi and baby Mario sprites by: jermungandr. Goomba sprites by: Murphmario. Goonies sprites by: Cheeseman. Kamek sprites by: Barack Obama and Murphmario. Fort/castle (stone walls), Fort/castle (towers) and full moon hills by: Barack Obama. Night sky by: Barack Obama and JigglyPuffGirl. Standard gradients by: MarioFanGamer.
Title screen (night version) (SMA3:YI) by: Jackster.
Sound effects by: Raccoon Sam and Yingchun Soul.
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More things:

-The bottom screen is, once again, changed. This time i replaced the star/ flower/ red coin with that...thing. Which also appears on the results screen.

Castle & Fortress BGM (SM:YIOSV) - Koji Kondo