<article>
    <header>
        <h1 class="special">Headline</h1>
        <h2>Subtitle</h2>
    </header>
    <p>Lorem Ipsum</p>
    <p class="special">Lorem Ipsum</p>
    <h2>Second headline</h2>
    <p>Lorem Ipsum</p>
    <p>Lorem Ipsum</p>
</article>

index.html

* {
    margin: 0;
}
article {
    margin: 0.5rem;
}
h1, h2 {
    font-family: sans-serif;
}
h2 {
    color: blue;
}
header h1,
header h2 {
    text-transform: uppercase;
}
article > h2 {
    padding-left: 0.5rem;
    border-left: 15px solid currentColor;
}
.special {
    text-decoration: underline;
}
p.special {
    color: blue;
}
header + p,
p + h2 {
    margin-top: 1rem;
}

index.css