How to make such an animation in css or in which direction to look?

Question

css

here is a gif, a sign with the name SVEN leaves, and on it a circle of light moves along the frame from below, and changes color when it moves, how to make such an animation in css

Answer 1

add ::after block and blend it on left from 100% to 0

Answer 2

if anyone needs it, I created a point with a frame thick, hung shadows and animation on it