If you want your post title centered, copy this code:
.post-title {
text-align: center;
}
Then go to Design>Customize>Add CSS
In the CSS box, paste the code. For some reason it won't change until I hit the space key. Make sure you're at the end of the code before you hit the space key or you might put a space in your code.
Once you see that it's centered, click Save.
That's it!
