Contact Form with Validation using JavaScript

What challenges did you encounter, and how did you overcome them?

I don't have much experience in writing HTML and CSS and I just start coding without thinking much about the layout at the beginning. Therefore, I spent a lot of time in CSS, and faced difficulties in the sector of "first name" & "last name" and query type. The code also looks messy because of different classes. I should think more about how to code the layout first at the beginning next time.