There are thousands of languages that compile down to JS. https://github.com/jashkenas/coffeescript/wiki/List-of-langu...

There are several languages that compile to CSS, like COMPASS and SASS.

There are various document formats that freely convert to and from HTML, like Markdown and DocBook. However, HTML is probably the most readable of JS/CSS/HTML.

While you can write native JS/CSS/HTML, you're inviting unintended complexity to your project whether or not you remember sending the invitation. There's nothing wrong with that, but you should be aware which choices are best for your team and for the scope and requirements of your project.