Experiments are a fun excuse to learn the latest tricks, think of new ideas, and push your limits. "Pure CSS" demos have been a thing for a while, but new opportunities open up as browsers and CSS itself evolves.
React and Vue are rather similar, although there are some key differences which. This makes sense as Evan You, the developer of Vue, used React as one of his inspirations. They are much more like one another than they are to say, Angular or Ember.
Most popular front-end frameworks used for developing generic designs that facilitate rapid prototyping these days are Bootstrap, Skeleton, and Foundation. Among the three, Bootstrap handles the lion’s share leaving Skeleton, and Foundation somewhat a mile distance.