Edit code for multiple articles in a category

Hi, I want to edit css for all posts for Gear category (Make the page full width 100%
), however Gear category archive page is also affected. Search results related to this category are also affected (search keyword: digital calendars). How do I solve it?

(I asked the same question before but due to busy work I ignored this error, now I think it affects the reader so decided to solve it)

The page I need help with: [log in to see the link]