Hacker News Reader

But BlueGriffon is discontinued. Today, nothing that is actively maintained fulfills this purpose, except from SeaMonkey Composer.

I wish there was a WYSIWYG editor that has CSS support and modern HTML.

Same here. Composer and to a lesser extend FrontPage Express taught me HTML and a bit of CSS back in 1997.

Also, the Seamonkey composer (which is the direct descendant of the Netscape tool)