Hi Lanna!

This happens because the style you're using and AO3 feeds use the same CSS class so some styling applies here and it doesn't fit the way AO3 display tags in their feeds.

I think if you go to http://www.dreamwidth.org/customize/options?group=customcss and add the following code to the big box ('Use embedded CSS) it should fix it:

.page-read .journal-type-Y .entry li .tag {
padding: 0;
}