title: Content does not size correctly to viewport
body: <p>I'm a beginner on CSS and HTML, and I have to fix a problem on this website:
  <a href="https://arena-supplements.com/" rel="nofollow noreferrer">https://arena-supplements.com/</a>
  on the Mobile Version, when you scroll left, you still see a lot of space outside the page.</p>
  <p>The problem seems to be the sticky header or this &quot;go to top&quot; button in the footer, but I have no other idea how to fix it.</p>
  <p>Would a max-width solve this?</p>
  <p><a href="https://i.stack.imgur.com/AbHEy.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/AbHEy.png" alt="enter image description here" /></a></p>