Remove “Category” from Page Headers

Hi. I would like to link people to a page that contains all posts with a specific tag/category. However, category pages all start with “Category:” followed by the category title (same with tag pages). I would like to remove the “Category:” and/or “Tag:” from the header of these pages. I’m okay at CSS and looked through the CSS of the site but can’t find anything that will fix my issue. Anyone know a solution?

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