The search bar will now behave in a "sticky" manner. This makes
the logo disappear more smoothly instead of being abruptly hidden.
Another upside is that the drop shadow will only appear once the
search bar is made fixed.
This also includes tweaks to the syntax highlighting theme
which were necessary to support switching the theme using CSS
variables. Some token colors in the light syntax theme have been
swapped around for consistency.
This closes#3041.
This also removes the need to load Web fonts, leading to a smoother
page loading experience.
Co-authored-by: Nicholas Hydock <nhydock@users.noreply.github.com>