Hi Nuttakorn,
Can you try by passing the sap-theme parameter in the url like below:
https://<host>:<port>/sap/bc/ui5_ui5/ui2/ushell/shells/abap/Fiorilaunchpad.html?sap-client=<client number>&sap-language=EN&sap-theme=sap_bluecrystal
Hope this helps,
JC