vue基于 element-ui 实现菜单动画效果，任意添加 li 个数均匀撑满 ul 宽度

鼠标移至图标上时使用toolTip显示对应的中文提示文字
<template>
  <div class="em_tool">
    <win :id="win.id" :data="win">
      <div class="nav">
        <input type="checkbox" class="nav__cb" id="menu-cb">
        <div class="nav__content">
          <ul class="nav__items" id="subnav">
            <li v-for="(item,key) in tool" class="nav__item">
 <!-- <span class="nav__item-text" prefix-icon="el-icon-users">{{item}}</span>-->
 <el-tooltip class="item" placement="top-start">
                <div slot="content">{{item.value}}</div>
                <el-button :ref="item.id" :icon="item.icon"  class="nav__item-text" @click="fn(item,key)"></el-button>
              </el-tooltip>
            </li>
          </ul>
        </div>
        <label class="nav__btn" for="menu-cb"></label>
      </div>
    </win>
  </div>
</template>

<script>
 export default {
    name: "em_tools",
 components: {
      win
    },
 data() {
      return {
        win: {
          id: "em_tool",
 title: "",
 top: "86%",
 show: true,
 width: 450,
 resizable: false,
 class: "em-tool-window"
 },
 input: '',
 tool: [
          {id:"tool_flyToScene",value: "menu1", icon: "el-icon-scene",control_id:"scene",fn:"toScene",trigger:"none"},
 {id:"tool_transparent",value: "menu2", icon: "el-icon-transparent",control_id:"em_slider",fn:"showFn",trigger:true},
 {id:"tool_coordinates",value: "menu3", icon: "el-icon-coordinates",control_id:"scene",fn:"xyz",trigger:true},
 {id:"tool_data",value: "menu4", icon: "el-icon-data",control_id:"scene",fn:"scene_data",trigger:true},
 {id:"tool_distance",value: "menu5", icon: "el-icon-distance",control_id:"scene",fn:"measure_drawLine",trigger:"none"},
 {id:"tool_area",value: "menu6", icon: "el-icon-area",control_id:"scene",fn:"measure_drawPloy",trigger:"none"},
 {id:"tool_hightly",value: "menu7", icon: "el-icon-hightly",control_id:"scene",fn:"",trigger:"none"},
 {id:"tool_label",value: "menu8", icon: "el-icon-label",control_id:"scene",fn:"measure_clear",trigger:"none"}......
        ]
      }
    },
 created() {
      var bodywidth = Number(document.body.clientWidth);
 var bodyheight = Number(document.body.clientHeight);
 console.log(bodywidth);
 this.win.left = bodywidth - 450;
 /*this.win.top=bodyheight-130;*/

 },
 mounted(){
      var subnav = document.getElementById('subnav'),
 aLi = document.querySelectorAll('#subnav li'),
 w = parseFloat(subnav.offsetWidth / aLi.length);//通过ul的宽度除以li的个数来计算每个li的宽度
 console.log("个数："+aLi.length);
 for(var i=0;i<aLi.length;i++){
        aLi[i].style.width = w + 'px';
 }
    },
 methods: {
      
    }
  }
</script>

<style lang="scss" scoped>
 @import "em_tools";
</style>

style部分
nav__item-text*, *:before, *:after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
.nav {
  overflow: hidden;
  float: right;
  right: 20px;
  bottom: 70px;
  width: auto;
  height: 60px;
  //background:linear-gradient(rgba(216, 187, 55, 0.8),rgba(20, 31, 55, 0.5));
  border-radius: 5px;
  -webkit-transform: translate3d(1%, 0, 0);
  transform: translate3d(1%, 0, 0);
  box-shadow: 0 10px 35px rgba(0, 0, 0, 0.2);
}
.nav__cb {
  z-index: -1000;
  position: absolute;
  left: 0;
  top: 0;
  opacity: 0;
  pointer-events: none;
}
.nav__content {
  position: relative;
  width: 60px;
  height: 100%;
  -webkit-transition: width 1s cubic-bezier(0.49, -0.3, 0.68, 1.23);
  transition: width 1s cubic-bezier(0.49, -0.3, 0.68, 1.23);
}
.nav__cb:checked ~ .nav__content {
  -webkit-transition: width 1s cubic-bezier(0.48, 0.43, 0.29, 1.3);
  transition: width 1s cubic-bezier(0.48, 0.43, 0.29, 1.3);
  background: url(../../assets/image/tool.bg2.png) no-repeat;
  width: 450px;
}
.nav__items {
  display: inline-flex;
  position: relative;
  width: 450px;
  height: 100%;
  padding-right: 45px;
  padding-left: 25px;
  list-style-type: none;
  font-size: 0;
}
.nav__item {
  display: inline-block;
  vertical-align: top;
  text-align: center;
  color: #bbb;
  font-size: 14px;
  line-height: 60px;
  font-family: Helvetica, Arial, sans-serif;
  font-weight: bold;
  -webkit-perspective: 1000px;
  perspective: 1000px;
  -webkit-transition: color 0.3s;
  transition: color 0.3s;
  cursor: pointer;
}
.nav__item:hover {
  color: #fff;
}
.nav__item-text {
  display: block;
  height: 100%;
  -webkit-transform: rotateY(-70deg);
  transform: rotateY(-70deg);
  opacity: 0;
  -webkit-transition: opacity 0.7s, -webkit-transform 0.7s cubic-bezier(0.48, 0.43, 0.7, 2.5);
  transition: opacity 0.7s, -webkit-transform 0.7s cubic-bezier(0.48, 0.43, 0.7, 2.5);
  transition: transform 0.7s cubic-bezier(0.48, 0.43, 0.7, 2.5), opacity 0.7s;
  transition: transform 0.7s cubic-bezier(0.48, 0.43, 0.7, 2.5), opacity 0.7s, -webkit-transform 0.7s cubic-bezier(0.48, 0.43, 0.7, 2.5);
}

.nav__cb:checked ~ .nav__content .nav__item-text {
  -webkit-transform: rotateY(0);
  transform: rotateY(0);
  opacity: 1;
  -webkit-transition: opacity 0.2s, -webkit-transform 0.7s cubic-bezier(0.48, 0.43, 0.7, 2.5);
  transition: opacity 0.2s, -webkit-transform 0.7s cubic-bezier(0.48, 0.43, 0.7, 2.5);
  transition: transform 0.7s cubic-bezier(0.48, 0.43, 0.7, 2.5), opacity 0.2s;
  transition: transform 0.7s cubic-bezier(0.48, 0.43, 0.7, 2.5), opacity 0.2s, -webkit-transform 0.7s cubic-bezier(0.48, 0.43, 0.7, 2.5);
}
.nav__item:nth-child(1) .nav__item-text {
  -webkit-transition-delay: 0.7s;
  transition-delay: 0.7s;
}
.nav__cb:checked ~ .nav__content .nav__item:nth-child(1) .nav__item-text {
  -webkit-transition-delay: 0s;
  transition-delay: 0s;
}
.nav__item:nth-child(2) .nav__item-text {
  -webkit-transition-delay: 0.6s;
  transition-delay: 0.6s;
}
.nav__cb:checked ~ .nav__content .nav__item:nth-child(2) .nav__item-text {
  -webkit-transition-delay: 0.1s;
  transition-delay: 0.1s;
}
.nav__item:nth-child(3) .nav__item-text {
  -webkit-transition-delay: 0.5s;
  transition-delay: 0.5s;
}
.nav__cb:checked ~ .nav__content .nav__item:nth-child(3) .nav__item-text {
  -webkit-transition-delay: 0.2s;
  transition-delay: 0.2s;
}
.nav__item:nth-child(4) .nav__item-text {
  -webkit-transition-delay: 0.4s;
  transition-delay: 0.4s;
}
.nav__cb:checked ~ .nav__content .nav__item:nth-child(4) .nav__item-text {
  -webkit-transition-delay: 0.3s;
  transition-delay: 0.3s;
}
.nav__item:nth-child(5) .nav__item-text {
  -webkit-transition-delay: 0.3s;
  transition-delay: 0.3s;
}
.nav__cb:checked ~ .nav__content .nav__item:nth-child(5) .nav__item-text {
  -webkit-transition-delay: 0.4s;
  transition-delay: 0.4s;
}
.nav__item:nth-child(6) .nav__item-text {
  -webkit-transition-delay: 0.2s;
  transition-delay: 0.2s;
}
.nav__cb:checked ~ .nav__content .nav__item:nth-child(6) .nav__item-text {
  -webkit-transition-delay: 0.5s;
  transition-delay: 0.5s;
}
.nav__item:nth-child(7) .nav__item-text {
  -webkit-transition-delay: 0.1s;
  transition-delay: 0.1s;
}
.nav__cb:checked ~ .nav__content .nav__item:nth-child(7) .nav__item-text {
  -webkit-transition-delay: 0.6s;
  transition-delay: 0.6s;
}
.nav__item:nth-child(8) .nav__item-text {
  -webkit-transition-delay: 0s;
  transition-delay: 0s;
}
.nav__cb:checked ~ .nav__content .nav__item:nth-child(8) .nav__item-text {
  -webkit-transition-delay: 0.7s;
  transition-delay: 0.7s;
}
.nav__btn {
  position: absolute;
  right: 0;
  top: 0;
  width: 60px;
  height: 60px;
  padding: 22px 17px;
  cursor: pointer;
  background: url(../../assets/image/tool_button.png) no-repeat;
  background-position-x: center;
}
.nav__btn:before, .nav__btn:after {
  content: "";
  display: block;
  width: 28px;
  height: 4px;
  border-radius: 2px;
  background: #bbb;
  -webkit-transform-origin: 50% 50%;
  transform-origin: 50% 50%;
  -webkit-transition: background-color 0.3s, -webkit-transform 1s cubic-bezier(0.48, 0.43, 0.29, 1.3);
  transition: background-color 0.3s, -webkit-transform 1s cubic-bezier(0.48, 0.43, 0.29, 1.3);
  transition: transform 1s cubic-bezier(0.48, 0.43, 0.29, 1.3), background-color 0.3s;
  transition: transform 1s cubic-bezier(0.48, 0.43, 0.29, 1.3), background-color 0.3s, -webkit-transform 1s cubic-bezier(0.48, 0.43, 0.29, 1.3);
}
.nav__btn:before {
  margin-bottom: 10px;
}
.nav__btn:hover:before, .nav__btn:hover:after {
  background: #fff;
}
.nav__cb:checked ~ .nav__btn:before {
  -webkit-transform: translateY(7px) rotate(-225deg);
  transform: translateY(7px) rotate(-225deg);
}
.nav__cb:checked ~ .nav__btn:after {
  -webkit-transform: translateY(-7px) rotate(225deg);
  transform: translateY(-7px) rotate(225deg);
}