Is changing the blue theme color possible?

go to style.css

and wherever it says #6897E5

change to #000 or what suits you.

designer’s advice: grey is rarely good color.

go to style.css

No, don’t do that. It’s not a good idea because when the theme is updated you will lose your changes.

If it’s just CSS then consider installing and activating a custom CSS plugin.

https://www.ads-software.com/plugins/search.php?q=custom+CSS

If you really want to “level up” (learning new things is cool) then consider creating and activating a child theme.

https://codex.www.ads-software.com/Child_Themes

Both options will let you safely make changes to your CSS.

Thanks guys… I actually do have a child theme currently installed and active. Will give it a shot!