So, what is this?
It is a nifty little feature to drag people's attention towards something special. It has to be used with caution, though, then too much of such a pulsating feature may easily become an annoyance.
To edit the contents inside the rounded container it would be best to add it temporarily to somewhere else on the on the page, with a text colour that makes it visible. When it has been finished, then position it in its proper place and change the styles to what you want.
It does not work in IE11.