我用vue-waterfall做瀑布流布局，希望兩列布局，兩列都緊靠屏幕兩邊，中間留出空白。上代碼：    <waterfall :line-gap='screenW'>      <!-- each component is wrapped by a waterfall slot -->      <waterfall-slot        v-for="(video, index) in videoList"        class='items'        :width='screenW'        :height='video.height * screenW / video.width + 40'        :order='index'        :key='video.auid'      >        <img :src='video.coverurl' alt="">        <div class='user-info-box'>          <img class='userlogo' :src='video.logourl' alt="">          <span class='userName'>{{ video.username }}</span>        </div>      </waterfall-slot>    </waterfall>        data () {        return {          screenW: window.screen.width * 0.49        }    }        這樣做出來是兩列緊靠在一起，居左，屏幕右邊留白了    然后我給index%2===0的加了marginLeft希望把右邊的頂過去，才想起來在左邊的index不一定是奇數，請問大神我應該咋辦