Losing CSS styling when exported from code pen

Hi guys,

My product landing page is working fine in code pen but I loose all the CSS styles when I export and unzip and open it in Index html file. What am I doing wrong?
here is the link for the code pen code

Are you linking to the stylesheet in your index.html file? I had to add it to the index.html file when I exported my tribute page from CodePen.

No I did not , Now I have added

to the Html file , and its still the same

It works now, thank you imlaurawelch!