How can I fix it?
What is in your index.html, can you paste/screenshot that?
Line 21 might be the problem. You dont specify which h1's you want to make white,48px and bold.
OR here's something that worked for me, if you write the font-family next to the other specifics on line 22
so the code looks like this :
font-family: 'Shift', sans-serif;
It sometimes takes it as mistake, even tho its stupid.