The problem of changing the background picture with vue computed combined with css hover

I dynamically bound a style to div, that is, using the calculation property to display the background picture by default, and then changing the picture when hover finds that the picture cannot be changed when the mouse is moved up, but the other properties take effect
< div class= "item": style= "topVal (0)" ref= "item1" >

.
           <router-link :to="{name: "qa"}" tag="p">aaaa</router-link>

< / div >

display the default background picture using the calculation property topVal
computed: {

        topVal(idx) {
            return idx => {
                return {
                    top: `${ idx * 103 }px`,
                    background: `url(${require("../../assets/images/homepage/bg.jpg")})0 -${idx*103}px no-repeat / cover`
                }
            }
        }
    },

then use css to change pictures with hover
&: nth-child (2) {

  &:hover {
  transform: rotate(360deg);// 
  background: url(../../assets/images/homepage/blueBg.jpg)0 -103px no-repeat / cover;// 
   p {// 
       color: -sharpfff;
   }

}
hover can"t change pictures if I bind a mouseenter event to div and use native js to set backgound, I can change pictures. Why

Mar.17,2022

try adding to css of hover ! important;
calculation attribute is written directly on style . If I remember correctly, the priority is higher than hover , which will directly cause the style of hover to be ignored

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