Tips on how to disguise +/- button in vue js with particular situation

How can I disguise the +/- button when there isn’t a merchandise at beneath?

Present Drawback
https://codepen.io/BorisNekezov/pen/BjgVoN <<<< css utilizing identical with this codepen

<template v-for="merchandise in SevenLengthlist" :key="merchandise">
      <ul>
        <li ><enter kind="checkbox" id="item-0"  /><label for="item-0">{{merchandise.mAcName}} --- {{merchandise.mName}}</label>
          <ul>
            <li v-for="item2 in merchandise.TenLength" :key="item2">
              <enter kind="checkbox" id="item-0-0" />
              <label for="item-0-0">{{item2.mAcName}} --- {{item2.mName}}</label>
                <ul>
                  <li v-for="item3 in item2.TenLength" :key="item3">
                  <enter kind="checkbox" id="item-0-0" />
                  <label for="item-0-0">{{item3.mAcName}} --- {{item3.mName}}</label>

                  </li>
                </ul>  
            </li>
          </ul>  
        </li>
      </ul>
    </template>