Why is it not taking my code?

I’ve reset the code, entered it several ways. It’s still not working, and I’ve been on this problem for roughly 2hrs. The original thread is no help.

.red-text { color: red; }

h2 {
font-family: Lobster, Monospace;
}

p {
font-size: 16px;
font-family: Monospace;
}

.smaller-image {
width: 100px;
}

.thick-green-border {border-width: 10px;
border-style: solid;
border-color: green;}

CatPhotoApp

A cute orange cat lying on its back.

Kitty ipsum dolor sit amet, shed everywhere shed everywhere stretching attack your ankles chase the red dot, hairball run catnip eat the grass sniff.

Purr jump eat the grass rip the couch scratched sunbathe, shed everywhere rip the couch sleep in the sink fluffy fur catnip scratched.

Update: I’ve solved the problem, and this post can be taken down.