How to use keyframes nesting in stylus

the original syntax of sass is to be transferred to stylus, but keyframes does not work anyway. The keyframes of stylus is followed by a classname. How to write the nested syntax of
name?
@ keyframes pic-404__child is also invalid
sass

.pic-404
    &__child
      position: absolute
    @keyframes
      0%
        top: 17px
        left: 220px
        opacity: 0
      20%
        top: 33px
        left: 188px
        opacity: 1
      80%
        top: 81px
        left: 92px
        opacity: 1
      100%
        top: 97px
        left: 60px
        opacity: 0
Mar.12,2021

$keyframe-name = (_ _ child)
@ keyframes {$keyframe-name}

.pic-404
    &__child
      position: absolute
     $keyframe-name = __child
     @keyframes {$keyframe-name} 
      0%
        top: 17px
        left: 220px
        opacity: 0
      20%
        top: 33px
        left: 188px
        opacity: 1
      80%
        top: 81px
        left: 92px
        opacity: 1
      100%
        top: 97px
        left: 60px
        opacity: 0
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