A SharePoint Online tutorial by Peter Kalmström
an earlier demo Peter Kalmström,
CEO and Systems Designer of kalmstrom.com Business Solutions, showed how to
add a link in the Content Editor web part to a text file containing the CSS
code in the Site Assets library, instead of adding the CSS code to the HTML
source of the web part.
This "link to CSS" method is quicker to change, as you don't have to open
the page in edit mode and then open the source. Instead you can make the change
directly in the CSS file.
snippet to the HTML source of the Content Editor web part, as described in
the previous demo, you can enter
the code in a .js or .htm file and save it to the Site Assets. Then you can
just add a link in the Content Editor web part.
Site Assets library.
Add a Content Editor web part to the page.