ERROR Here: Each .main-section should have an id that matches the text of its first child, having any spaces in the child’s text replaced with underscores (_ ) for the id’s.
This problem I can’t solve. How can I sovle it? when I used in #Introduction id? Other Id I can solve ex: id=“JavaScript_and_Java” there I used id=“#JavaScript_and_Java” it’s works but my problem create when I use id=“Introduction” there I used id=“#Introduction”.