树，设置check-change时，点击行选中，点击三角符号可以展开，但是颜色不受控制，

/deep/ .el-tree-node:focus > .el-tree-node__content {
  background-color：red; }

找了半天的问题，，，这么一句，记下来，难受。

               <el-tree
                  :data="treedata"
                  accordion
                  node-key="id"
                  ref="tree"
                  highlight-current
                  :props="defaultProps"
                  @check-change="handleCheckChange"
                  check-on-click-node
                ></el-tree>

 记录一下悬浮颜色修改

/deep/ .el-tree-node__content:hover {

  background: rgba(255, 255, 255, 0.05);

}

/deep/.el-tree--highlight-current

  .el-tree-node.is-current

  > .el-tree-node__content {

  background-color:  rgba(35, 220, 205, 0.78);

}

/deep/.el-tree {

  background: #10498f;

  color: #ffffff;

}

/deep/ .el-tree-node:focus > .el-tree-node__content {

  background-color:rgba(35, 220, 205, 0.78);

}