Prework
Description
The CSS of the pkgdown website changes considerably between the stable version and the dev version. For example:


I'm not sure whether this is voluntary but it seemed weird to me and I didn't find any issue on this.
Reproducible example
Not applicable
Expected result
Same style for both (I personally prefer the style of the dev version)
Session info
Windows 10
Tested with Chrome 116 and Firefox 116, same behavior