On my blog post page, it shows like 20 lines of blank spaces and then the "Read More >"
On my blog post page, it shows like 20 lines of blank spaces and then the "Read More >"
Not sure it is easy to control that. You could probably just put a bunch of horizontal space after what you want to show, but the space will probably show up in the preview.
Since that part of the UI is controlled by FANDOM code that is not easily customizable your best bet is to ask FANDOM staff via "Contact us".
The following CSS code seems to work. It strips out any blank lines in the preview after the first 5 in sequence. It will affect the preview itself in case there are so many <br> tags in sequence there, but I think this is rare.
div.post-summary>br+br+br+br+br+br { display:none; }