Looking deep in the problem using the siddartha’s example, i realized that in ionic.css .col-70 and .col-30 don’t exist.
I think that the documentation could create a little bit of confusion because in the Grid: Explicit Column Sizes section says:
An advantage with this grid system is that you only have to state the percentage for the column that needs it, and the others will still evenly divide up the available areas.
But in the ionic.css there aren’t all the decimal percentages.