config file to SASS file convertion

I was asked to build a tool that generates a SASS file for a pre-built HTML file.

In which I have:

• A 'CONFIG.TXT' file which is used for the user to give out information as to which will be the primary color of his website or what gallery type he wants to have, etc.

• This 'CONFIG.TXT' will then be process by said tool and generate a SASS file that will make the desired changes to the pre-built website.

EXAMPLE: Website primary color is blue. (h1 and h2 tags), in the 'CONFIG.TXT' file I would type in 'Primary Color: red', run the 'CONFIG.TXT', through the tool and it would give out a SASS file with the changes to the tags that needed to be changed.

What would be the easiest/simplest way to make such a tool? What program language to make the tool itself? (I was thinking Python) and also what modules/Libraries would be usefull for this kind of tool.

Thank you in advance and Im sorry if you did not understand something (Bad English).