Portfolio Project help. Why doesn't the background color of my contact section fill the entire section?

https://codepen.io/kaija-montaine/pen/VBwwNY

The “box” that contains an element by default only expands enough to fit its content. If you explicitly add

width: 100%;

to your #contact class style, it will fill the entire width of the page.

Btw I noticed you have a #contact and #Contact. That’s not a good practice.