[myfonj]

I can hardly judge, but that "Edit Here" "Reload Here" concept, being necessary to understand at first, seems not as necessary to keep after the point reader grasps the fact "this is source file and that is it rendered appearance". Live preview like complex Thimble [1] or simple Scratchpad [2] or Dabblet [3] seems to be far more convenient for exploring fundaments of HTML / CSS, especially for beginners.

In fact I have such one "scratchpad" crammed into data:uri and bookmarked and keep regularly using it to quick test almost anything HTML / CSS / XML / SVG / JS related. (I am coder.)

[1] https://thimble.mozilla.org/ [2] http://scratchpad.io/ [3] http://dabblet.com/