Some elements look different (weird margins, paddings, width, etc..), what to do?
It's caused by CSS conflicts. Some plugin or the theme has higher CSS specificity rules declared. Luckily from plugin version 4.0 there is an option you can adjust to increase CSS compatibility level.
Go to Compatibility Options -> CSS compatibility level and change it to Maximum
- Save your search instance settings again afterwards, just to make sure, that the stylesheet is properly generated
- Don't forget to clear your site and browser cache afterwards (including Cloudflare if you are using it)