Not able to set a section of a webpage to full viewport height[CLOSED][FIXED]

HTML-CSS
#1

I’ve thoroughly checked multiple times and tweaked the code a few times. Everything else works but still I am not able to set the section with the id of “welcome-section” to full viewport height. All help and responses are appreciated : )

Here is the link to the code:
https://codepen.io/x-spec/pen/XWjeLWQ

#2

Cut all the css from the html section and paste in in css section. Your work will be done. Check your code pen now

Code Pen

#3

Thank you so much for the help! It’s fixed now.