Change the font size of any element test

I cant seem to get this right the second P element got the size change whereas the first did not here is my code:
.red-text {
color: red;


.red-text { color:red } p {font size= 16px; }

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

Any help would be much appreciated

I think it might be because you’re using an equal sign in css when it expects a colon. p {font size= 16px; } should be p {font size: 16px; }