This is by design -- for HTML files, the unused size shown is the sum of all unused CSS and JS and does not include anything else. We don't have data for actual HTML which generally should not be presumed entirely useless, so we don't want to confuse user by showing "red" for something that is not necessarily unused. We could in theory use third color for this, but we previously decided against that. If you have idea what's the right thing to do there, please let me know.

Let's reopen if we find a better way of handling this.