:class数组写法

<div :class="[
      activeTag, 
      activeCss,
      { 'red-btn': isPosition}
]">

computed: {
      activeTag() {
          return this.fullState == 3 ? 'yellow-btn' : 'gray-btn'
      },
      activeCss() {
          return this.audience ? 'yellow-btn' : 'gray-btn'
      },
      isPosition() {
          return this.state === 1
      }
}

.gray-btn {
      color: #666666;
      background: #ececec;
}
.yellow-btn {
      color: #ffffff;
      background: #ffaa1e;
}
.red-btn {
      color: #ffffff;
      background: red;
}