Notification page with React

I divide the notification section into types of notifications (react to post, followed, private message, ...).

All the notifications are sorted by time property in Data.jsx. The time from posting is calculated and transformed relatively because I ignore some differences of days in month, leap years. It might be wrong in a long amount of time but with a short one, I think it's fine. If you know any more efficient ways, please help me with that.

I also have problem with grid. Some lines in CSS, display: grid, grid-template-columns, grid-column, grid-row, have warning "is not supported by Safari < 10.1". I don't know how to solve this problem.

Any suggestions about other things are appreciated. Thank you!