How do I create a style css for the main.min.css in the child theme?

Hi. I am trying to edit the front page of the Hueman theme to make the font more darker from my child theme style.css but I am unable to. When I use the “Inspect Element” feature in Chrome, I see that I should edit the main.min.css . I edited it directly but I want to create its equivalent in the child theme to ensure that that I do not lose the changes on update. How do I create that? I import the main.css from the parent theme using functions.php in the child theme. My site is here