To create those soft light spots, you could use circles with radial gradient. So you would open the color panel and change it from Solid Color to Radial Gradient, and once you have done that, you should see a preview next to the paint bucket. To change the colors, you can click on one of the arrows at the bottom and then change color of it, you can also make the color transparent by changing the alpha, next to the "A". you can also drag the arrows to change the area where the color starts, and add an arrows by clicking anywhere below the colored strip. Once you have created a gradient that you want to use, you can use the circle tool to draw a circle, and if you hold down shift + alt while dragging, it will create a uniformed circle. If the circle got outlines, you can just use click on the outlines with the black arrow and then delete them. If you want to change the color of a circle you already created, you can click anywhere on the colored area to highlight it and then change the color in the color panel. Then you can convert different circles to symbols so that you can reuse them in multiple places, by selecting one of them and pressing F8. With cycles converted to symbols, if you edit one of them, it will update all other copies of that symbol. For the animation you can create symbols that hold multiple of the circles, so you could have the smallest circles in one symbol, bigger circles in another, and the bigger circles inside another. Then you can animate each of those symbols on different layers, to move at different speeds to give a bit of a parallax effect.
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