Cyclic animation of the card, how?

Question

css

Hello.
There is such a picture - https://imgur.com/a/NxCsp
The task is to loop it in the animation shift to the right / left (does not matter) the effect is like it floats.
How I tried to do it: I
put the image as an absolute, stretched it by 100%, made background-image: repeat-x i made the keyframe from 0 to 100% shifted the background position by 2000% for 300 seconds. The problem is when the offset reaches these 2000% - it jumps to 0% and it is very noticeable, that is, the animation is not cyclic, it does not go in a circle.
It needs to be done in css.
Thanks in advance