Who can tell me the origin and background of the song "City of the Sky"?

Sky City is an animated film released by Studio Ghibli in 1986. The original work, producer, script and role setting of City in the Sky are all handled by Miyazaki Hayao, which makes this work full of Miyazaki Hayao's thoughts from beginning to end. Lapda, a castle in the sky, is generally regarded as a flying island country in Gulliver's Travels (published in 1726), a famous novel by British writer jonathan swift. Later, an online game of the same name was developed. The City in the Sky is Gulliver's Travels, a novel written by jonathan swift in Miyazaki Hayao. Some people think that its story is traditional, but this does not mean that it is not original. On the contrary, the play City in the Sky is full of many new elements. This film almost perfectly depicts the landscape of the world when the story takes place, which is a little sci-fi, a little myth, and a little industrial revolution in Europe, such as old trains on elevated tracks, dark mines, flying ships, robots like clay sculptures, etc ... The tense plot runs through the whole film, but the blue sky and thick white clouds dilute the sharp conflicts and are more intriguing; The performance of characters often depends not on lines, but on the specific actions of characters, which makes them more profound. Sheeta, a little girl, is descended from the legendary "Lapda" royal family. It used to be an aerial civilization that surpassed the above-ground civilization for thousands of years, but somehow, Shu Da's ancestors left the "city of the sky", abandoned the developed technology and lived a secluded life on the ground. However, one day, several unidentified men appeared in front of her house ... The story of Paso and Hida began when Hida's army was attacked by pirates in the air on the spaceship. In the struggle, Hida fell from a flying boat at an altitude of 10,000 meters ... Bath, another hero of the story, was an apprentice of a miner pilot. When he got off work that day, he found a shiny thing falling slowly in the sky. What is this? UFO？ He flew over and found a lovely girl floating down from the sky surrounded by blue light ... The next day, Sida woke up in Bath's room and found a photo of Laputa, the city of the sky. This is the real sky city filmed by Bath's father at the risk of his life, but no one believes him except Swift. So my father died of depression. Bass vowed to prove to others that there really is a city of the sky in the world! Pirates with a keen sense of smell soon found us. Then there was a dazzling chase scene. Finally, the two men fell into a deep mine in full view, and the flying stones of Hidadai shone again, making them fall safely. In the mine, flying rocks and underground ore are ringing. This used to be the place where raw materials of flying stones were mined, but the technology of extracting flying stones is said to be in Lapda's hands. As soon as they got out of the mine, they were caught by the army. Hida was taken to the fortress, and a man named Musca showed Hida a huge robot, saying that it fell from the city of the sky, and the technology at that time could not be restarted. That night, Hida read the help spell circulated by her ancestors, and the flying stones shone, bringing the robot back to life and turning the whole fortress into a sea of fire. Bass took advantage of the chaos to form an alliance with pirates and flew into the fortress to rescue Hida. In desperation, Hida lost the flying stone, and Musca got the gem, and ordered the army to fly to the city of the sky under the guidance of the holy light on the gem. On the other hand, the pirate mother calculated the location of the city of the sky from Hida's account, and took Hida and the two of them to take the pirate airship at full speed! When we were about to arrive, a tornado suddenly appeared in front of us, and we met Musca's ships in a narrow way. During the battle, Buzz and Hida's glider were involved in a tornado. This is a land abandoned by God. The horror of nature and the anger of the gods gather here, flying over the thick darkness, passing through the lightning corridor in the roaring lightning, breaking through the boundary between life and death, and the door of fate is opened again in front of the teenagers ... The center of the tornado is the legendary flying island "Lapda, the city of the sky"! This is a quiet paradise, only robots are on duty in the sky, and plants and ancient creatures are home. In Miyazaki Hayao's works, the best technology is that no one lives there, whether it is Conan's Future World or Sky City. On the contrary, the only people struggling for survival in Valley of the Wind are ancient science and technology, but they are the owners of machines, and so are the Snitch in City of the Sky. Musca caught the pirates and came to Lapda. He forced Hida to enter the central control room with him, started writing on the black stone tablet, and was about to start his ambition to dominate the world. Hida got the flying stone back. In order to stop Musca, she and Buzz read a curse to destroy everything: Barros. Laputa disintegrated, the evil weapon system assimilated into a fireball and fell into the sea in the atmosphere, while the huge slungshot crystal floating in the air carried Laputa's tree of life to the end of the sky. ...