container text-center (outside of grid-system)
auto fit in remaining space (row1)
new content (r1c1)
same row, new column (r1c2)
row 2 column 1 (r2c1)
row 2 column 2 (r2c2)
a third row (r3c1)
a nested row (r3Ac1)
and a column within that nested row (r3Ac1)
a second column of text (r3Ac2)
a fourth row to show the boundaries of the third more clearly