Why is the nav not sticking to the top of the page?

Question

https://code.sololearn.com/WFm6OCkF5dW6/?ref=app

Answer 1

On mine, only 1/3 of the nav can be seen when scrolling down. So strange.

it is working fine on codepen.

Answer 2

you should use 'fixed' rather than 'sticky' to 'position' property of #navbar...

... and then reset the top property of #welcome-section to zero ^^