Project: react
Task (challenging): 1) Create utils/toast.tsx to display a one-line message (fontSize: 12px) in a appealing green box at the top of the page for 2000ms. 2) Display a toast with 'New Comment Created Successfully!' when a new comment is submitted, and 'New Blog Created Successfully!' when a new blog is submitted. 3) If a toast is already visible when another is triggered, remove the old toast before showing the new one. 4) Constraint: DO NOT use any third-party packages; ONLY React APIs are permitted.