Fix sticky bit not being sticky

The article progress indicator is supposed to be sticky. The positioning got broken by some overflow on the page.

src/app/pages/blog/blog.scss

@@ -5,6 +5,7 @@
     background-color: ui-color(white);
     justify-items: center;
     width: 100%;
+    overflow: clip;
 
     section {
         width: 100%;