const columns: ColumnsType<FileInfo> = [
    {
      title: '文件名',
      dataIndex: 'file_name',
      key: 'file_name',
      ellipsis: true,
      render: (text: string) => <Text strong>{text}</Text>,
    },
    {
      title: '文件大小',
      dataIndex: 'file_size',
      key: 'file_size',
      width: 120,
      render: (size: number) => formatFileSize(size),
    },
    {
      title: '上传时间',
      dataIndex: 'uploaded_at',
      key: 'uploaded_at',
      width: 180,
      render: (date: string) => formatDateTime(date),
    },
    {
      title: '操作',
      key: 'actions',
      width: 220,
      render: (_, record: FileInfo) => (
        <Space size="small">
          <Button
            type="link"
            icon={<EyeOutlined />}
            onClick={() => handlePreview(record)}
          >
            预览
          </Button>
          <Button
            type="link"
            icon={<DownloadOutlined />}
            onClick={() => handleDownload(record)}
          >
            下载
          </Button>
          <Button
            type="link"
            danger
            icon={<DeleteOutlined />}
            onClick={() => handleDelete(record)}
          >
            删除
          </Button>
        </Space>
      ),
    },
  ];