vue动态点击添加样式

<input
            type="text"
            v-model="item.value"
            style="padding: 1vh 0; height: 3vh; margin: 1vh 0"
            :class = "isclass == index ? 'addclass' : '' "
          />
          <input
            type="password"
            v-model="item.value"
            style="
              padding: 1vh 0;
              height: 3vh;
              margin: 1vh 0;
              position: absolute;
              right: 0;
              color: black;
              opacity: 0;
              border: none;
            "
             @focus="inpFocus(index)"
          />

const isclass = ref(-1);
    const inpFocus = (index)=>{
      isclass.value = index;
    }

.addclass{
border: 1px solid red;
}