Oxygen 2.1 is a fantastic visual builder application for WordPress.  At first, I was a little hesitant about using a builder that was not based on the traditional theme building of WordPress.  However, I am now coming around to Oxygen's method of building web sites.  Sometimes using themes is a bit annoying because some themes are too complex.  They try to give you more and more options.  The code is like a complex series of containers like a bunch of Russian dolls within other Russian dolls like a never ending battle against truth and bugs.  It becomes harder to figure out because of the multitude of layers.  For example, if you do a code inspection you see layers upon layers of css code, much of which is over-ridden and not even used.

The Oxygen plugin is built on flex-box, a css system for arranging items on a page.  For example, take a look at the 3 boxes above for an idea of what the flex system does for us.  Drag your browser window to see what happens when the viewport shrinks.