In some cases you may need to add custom CSS styles to the Kunena template. It is easy to do.
You need to edit a custom LESS file via back-end. Go to Kunena > Templates, then select RND template [name] using radio button and click on Edit LESS button. Then select custom.less file and click on Edit LESS again.
![Select required template and click on Edit LESS button](/images/docs/kunena-template-edit-less1.png)
![Select custom.less and click on Edit LESS button](/images/docs/kunena-template-edit-less2.png)
Now you can add your custom CSS rules. After clicking on Save button your rules will be compiled.
Note: Do not forget to clear browser cache and Joomla cache after each changes made in custom.less file!