My first assignment was to construct a tiny pixel game for my web site. It's not fun to play, but it contains enough tech to teach me the basics about transforming, bluring and to get the general idea of how these things are done; and to my surprise was actually fun to do! JavaScript is not at all a bad language (for prototyping), it just didn't have HTML5 when I tried it 10 years ago.
The start button and the game itself is 230 lines, the flashy text is 120 lines (both are about 50/50 CSS/JS). Here's the text.
The blur in/out is done by CSS, the individual adding and removal of each letter in the text is JS, although it probably could be done in CSS. CSS3 is still only configuration, not programming, which of course is good; and although there are some flaws (missing inheritance), I feel CSS3 is good enough.
I should use this for prototyping dull stuff like menus. When it looks good, I'll implement in C++. When you know exactly what you want, C++ isn't bad, but when you want to iterate small and large changes CodePen is a whole lot better.