Why do the knowledge base pages look wrong?

Two causes account for almost every styling complaint.

The theme is winning the specificity fight

Some themes and page-builder addons set colours, spacing and fonts on bare element selectors, which will override a plugin’s styling. Turn on Force styles over theme under Advanced in Settings — that loads a build of the stylesheet which takes precedence.

If the knowledge base instead looks fine but too disconnected from the rest of the site, turn that option off and let the theme show through.

A stale template is left in the theme folder

If a previous version of the templates was copied into the active theme, and theme overrides are enabled in Settings, that old copy will be used instead of the current one. The usual symptom is a page that renders twice, or a section that will not go away no matter what you change.

Either delete the copies from the theme folder or switch Allow theme template overrides off.

Fonts look different from the rest of the site

Set the font source to “inherit the theme’s fonts” in Settings. The knowledge base will then use whatever typography the theme already establishes.