In Firefox the horizontal scrollbar looks very small. With a width set
to `auto`, it looks bigger and better. In Chromium, without an automatic
height, the new color changes do not appear.
Now the horizontal scrollbar looks consistent in both chromium and firefox.
In order to match the theme presentation
(https://i.imgur.com/cCiHOGS.jpg), the previous defined `height: 7px` and
`border-radius: 10px` for the scrollbar have been deleted.
Change the horizontal scrollbar styles in Archives page following the
dark and light themes styles. This horizontal scrollbar is at the top
of the Archives page. When I visit this page, the scrollbar stole my
attention. Unfortunately, it's the client (our browser) who decides its
styles; this change is introduced to avoid that situation.
Co-authored-by: Miguel Angel <man98@me.com>
