Is it possible to use other tags within the h1 tag (or h2, h3, h4, etc.)? For example:
span {
color: red;
}
strong {
text-decoration: underline;
}
<h1>My <span>example</span> text</h1>
<h2>Can I <strong>use</strong> it?</h2>
<h3>Why do you think so ... ? </h3>
Are these code examples valid and will they appear correctly for SEO purposes?