?How to change Biolife - Organic Food WordPress Theme color

I mean How do customize or change Biolife - Organic Food WordPress Theme color?
and when i try importing XML it keep giveing me this error:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator at webmaster@didwaonline.liyonzydesigns.com to inform them of the time this error occurred, and the actions you performed just before this error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.
Apache Server at didwaonline.com Port 443

Hello @Liyonzy,

I also asked the coder. And he explained that there are some positions / places that can be changed in Theme Options. Some others must be changed in code. So please show all the positions that you want to change then provide me your admin + FTP account, we will check and help you

Regards,
Yame