add "see more" on multi-column text

[leleodddd]

Hi everyone !

I would like to add a "see more" link in my multi-column section texts but only for mobile. (because it's not very sexy to have that much texts on mobile)

I saw a lot of questions about "see more" for products or collections, but not about multi-column and texts.

Let see : 

On desktop , it's ok

On mobile :

Texts are too long, that's why I would like to add "see more" link and then the entire text appear : 

Good to know : 

- I use the prestige theme

- My website is in french language, so it has to be "voir plus" (= see more)

- multi-column section => image with text

- There 4 texts

If anyone can explain me the right code or the right way to do it please ?

Many thanks !!!!

Best,

Lea