[theducks]

the whole book does not need to use a style sheet. You can edge in.


As to importing ' A style sheet':
Unless the 'Imported' sheet is designed to work on a tag level (sets a basic style), you are wasting effort.

So in you example, you could start with a 'New Stylesheet'
add the ONE selector:

.hideheader {text-align: center; display: none;}

Select ALL the HTML files you want to use this style in the Book Browser:
right-click: Link stylesheet: tick the box for the stylesheet: OK

Using Search and Replace: replace all the

style="text-align: center;"

with

class="hideheader"

Then slowly shift other styling over to the stylesheet..
Note: that if you move a style defined in the head of a document, be sure to remove it from there as it can override the stylesheet.