Mobile first using CSS and JS

Hey guys I just finished these project .I didn't know how to create these small upside down triangle when the share icon is clicked on the desktop version so mine is a little different 1 so any comment on how I could have done that ? 2 I have to "row" classes with the same content on the html file .that hold the social media icons which I know it is not efficient but I didn't know how to manipulate the same class in different breakpoint through JavaScript