General fixes and additions

- Improve readability on larger and smaller screens
- Re-add page signing with a custom script (which is signed of course)
- Posts are now centered on large screens
- <code> now stops overflowing and receives a scrollbar
- The mobile page now stops to overflow

content/about.html

@@ -28,5 +28,6 @@
 <h3>About This Page</h3>
 <ul>
     <li><a href="https://{{ git_url }}/PapaTutuWawa/blog.polynom.me">Source</a></li>
+    <li>All pages are signed using my public key. Use this <a href="/assets/files/verify.sh">script</a> (<a href="/assets/files/verify.sh.sig"><u>signature</u></a>) to verify</li>
     <li>Last updated <i>{{ build_time }}</i></li>
 </ul>