Firefox emphasizes the main part of the domain name in darker text, so "ycombinator.com" is black while the rest of the URL is grey.
Chrome uses slightly darker text for the whole domain name, so "news.ycombinator.com" is black while the rest of the URL is grey — but the difference is so slight that it's nearly impossible to see. I don't know why they would bother to make the distinction and then make it visually indistinguishable.
Safari shows just the domain name, "news.ycombinator.com".
Firefox emphasizes the main part of the domain name in darker text, so "ycombinator.com" is black while the rest of the URL is grey.
Chrome uses slightly darker text for the whole domain name, so "news.ycombinator.com" is black while the rest of the URL is grey — but the difference is so slight that it's nearly impossible to see. I don't know why they would bother to make the distinction and then make it visually indistinguishable.
Safari shows just the domain name, "news.ycombinator.com".