[SOLVED] How do I make my cards and quote fluid?

This is my first codepen site:

Please help me make my card elements and quote fluid, in order to be correctly rendered on a mobile phone.
Also, if I type the "li"s directly into the jumbotron (not as I did in the second card), how do I make them stay in the center? A simple alignment just puts the text in the center, but I want also the bubbles in the center.

Later edit: I solved the issue by adjusting the columns with custom offset.