There was a slight difference (between index.css and taskbar.css) in the
margin values of the UI language selector button, however the values
taken from taskbar.css don't seem to have any visible impact on the
welcome/library page (controlled by index.css).
Moved from index.css into kiwix.css some CSS with global effect thus
making it apply to the viewer too.
Extra font-size directives in taskbar.css are needed to undo the effect
of 'font-size: 62.5%' now applied to the 'html' element type.
The new file kiwix.css is intended to host the intersection of index.css
and taskbar.css. In this commit only font definitions have been moved
into it.
Veloman Yunkan