After reviewing this particular question, I found that the suggested solution did not yield the results I was hoping for.
Here is a visual representation of the issue: https://i.sstatic.net/Nj5V0.png
My goal is to substitute the text "Select subscription plan" with "All plans come with a 7-day free trial." Through experimentation, I came up with the following CSS code:
.discourse-subscriptions-section-columns .section-column div > p:after {
content: "All plans come with a 7-day free trial!"; }
However, even after applying this code, the original text still lingers. Upon further attempts with the CSS below:
.discourse-subscriptions-section-columns .section-column div > p {
visibility: hidden; }
I realized that using the above code resulted in hiding everything on the page, rather than just the targeted portion ("Select subscription plan"). This dilemma leaves me unsure about the next steps to take in order to achieve the desired outcome...