flex实现左中固定不变，右边自适应

.tab1-main {
    display: flex;
    justify-content: space-between;
    align-items: stretch;
    .tab1-tree {
      width: 300px;
      padding: 10px;
    }
    .tab1-line {
      flex-basis: 10px;
      flex-shrink: 0;
      border-left: 1px solid #dcdcdc;
    }
    .tab1-table {
      flex: 1;
      min-width:0;
    }
  }