如何设置'REUSE_ALV_GRID_DISPLAY'的单个单元格的颜色

REPORT  ydemo_rick_a .
TYPE-POOLS: slis.
DATA: BEGIN OF it_flight OCCURS ,
       carrid  LIKE sflight-carrid,
       connid   LIKE sflight-connid,
       fldate   LIKE sflight-fldate,
       seatsmax LIKE sflight-seatsmax,
       seatsocc LIKE sflight-seatsocc,
       color TYPE lvc_t_scol,
      END OF it_flight.
DATA: it_fieldcat TYPE  slis_t_fieldcat_alv,
      layout TYPE  slis_layout_alv.
CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'
  EXPORTING
    i_program_name         = sy-repid
    i_internal_tabname     = 'IT_FLIGHT'
    i_inclname             = sy-repid
  CHANGING
    ct_fieldcat            = it_fieldcat
  EXCEPTIONS
    inconsistent_interface =
    program_error          = .
SELECT  carrid
       connid
       fldate
       seatsmax
       seatsocc
FROM sflight
INTO CORRESPONDING FIELDS OF TABLE it_flight
UP TO  ROWS.
DATA: col TYPE lvc_s_scol,
      coltab TYPE lvc_t_scol,
color TYPE lvc_s_colo.
color-col = ''.
color-int = ''.
color-inv = ''.
LOOP AT it_flight.
  IF it_flight-seatsocc EQ .
    col-fname = 'SEATSOCC'.
    col-color = color.
    APPEND col TO coltab.
    CLEAR col.
    it_flight-color = coltab.
    MODIFY  it_flight.
  ENDIF.
ENDLOOP.
layout-coltab_fieldname = 'COLOR'.
CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
  EXPORTING
    i_callback_program = sy-repid
    is_layout          = layout
    it_fieldcat        = it_fieldcat
  TABLES
    t_outtab           = it_flight
  EXCEPTIONS
    program_error      = .