W3C Validation errors | WordPress.org

Hi,

I’m using Stackable plugin with Blocksy theme. I am in the process of removing errors found with W3C validator.

I still have to fix some CSS parse errors and incorrect divs in the layout. The bugs that remain are related to Stackable classes.

Example page with errors: https://validator.w3.org/nu/?showsource=yes&showoutline=yes&doc=https%3A%2F%2Fseptero.pl%2F#l14c109

How to get rid of above-mentioned errors?

Thank you for support.

With best regards