Display large text message in a separate popup or screen

Hi team,

I have a gridfield where a gridcolumn has a value who's character count can go upto 2500. I want to implement a functionality where i display only 200 chars and show a link "more". When I click on the link, either a popup appears where the entire 2500 char text is displayed or another site appears to display the whole value. How can I achieve this? I tried to use safelink, but I am not sure how to configure the uri to display the text. Can anyone please help me out.

So far, i have achieved this,

a!gridColumn(
            label: "Enter 2500 char text",
            value: a!richTextDisplayField(
              value:{a!richTextItem(
                text: left(fv!row.textValue,255)
              ),
              a!richTextItem(
                text:"..more",
                link: a!safeLink(
                 
                )
              )
              }
            )
          )