Invalid reason after adjustment: adjustment error, the spacing before/after the paragraph should be adjusted. The gap between the first-level titles and the second-level titles in the Word catalog is not "line spacing", but "spacing". Because each title in the Word directory is a separate paragraph, what needs to be adjusted is the spacing between paragraphs. Here, use Word 2007 to demonstrate the operation process of changing the title spacing in the directory:

First, open the Word document, find the titles whose spacing needs to be adjusted, and select these titles. For example, the spacing between the two titles in the picture below is too large, so choose these two titles.

2. After selecting these titles, enter the start menu and click to open the paragraph window.

Third, according to personal needs, adjust the spacing before or after the paragraph, and finally click "OK".

4. As shown below, after the spacing before the paragraph is changed to 0, the spacing between the first-level title and the second-level title becomes normal.