Good dogs

OK, I messed up somehow. Here's what I did:

<style>
    h1, h2, p {
        font-family: sans-serif;
    }
    h2 {
        color: white;
        background-color: black;
        margin: 0.5rem;
    }
</style>
<h1>Good Dogs</h1>
<h2>Renata</h2>
<p>Renata is a good dog.</p>
<h2>Rosie</h2>
<p>Rosie is a good dog, too.</p>

(Notice how I applied styles to <h1>, <h2>, and <p> all at the same time? Cool!)

It looks like this:

That's not what I want. I want this:

Please fix the code for me. Do it by changing as little as possible.

Upload the fixed file. Submit the URL.