Hello
I don't know what you're trying to do, but You are asking for something
modern Internet has not invented. I had the same questions years ago
when I started my "computers" website, and I finally went with FrontPage
through WINE. The code looks very awful in all versions except 2003, in
which at least part of comments can be turned off (so it looks just
awful now), but this is the best thing I could find. 
A few months ago I was looking for such thing again, when I planned to
write documentation for my program, and found Brackets editor for
coding pure HTML/CSS, it has some "fireworks" such as auto-refreshing
preview but nothing like WYSIWYG.
When I saw PHP errors in CSS (!) of my workplace's website I had to
revise my opinion about FP's output code quality :-) .
For Linux apps, in supported ones, you have SeaMonkey Composer. This is
near Mozilla Composer. Nvu/Kompozer is dead for a long time and
BlueGriffon probably went totally closed source.
Additionally, I was looking for HTML editor just with Screem's
capability of renaming site's hyperlinks with renaming files and even
this feature seems to be absent from programmers' editors now!

Unfortunately, now IMHO, there won't be such thing at all. Modern
Internet doesn't work this way anymore, it is more focused on ads than
for content and for ads you only need a good PR experts and code
mechanic who will embed their things into "app".

MCbx