It’s actually not recommended to replace CSS class names as it might break the site. But if you need to replace them there’s a way around which needs a bit of coding skill.
For example: If you want to replace css class name “woocommerce-xyz” to something like “wc-xyz”, then you’ll need to add following replacement in “replace in html”:
woocommerce-xyz ==> wc-xyz
Then copy the css code from for wp-navbar from respective css file, replace occurrences of “woocommerce-xyz” with “wc-xyz”, and add it in “Internal CSS” option in HMWP Source Code tab.