Learn Accessibility by Building a Quiz - Step 17

Tell us what’s happening:
Describe your issue in detail here.
how can i add sans-seriff as a fall back for the font
Your code so far

<!-- file: index.html -->
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="freeCodeCamp Accessibility Quiz practice project" />
    <title>Accessibility Quiz</title>
    <link rel="stylesheet" href="styles.css" />
  </head>
  <body>
    <header>
      <img id="logo" src="https://cdn.freecodecamp.org/platform/universal/fcc_primary.svg">
      <h1>HTML/CSS Quiz</h1>
      <nav>
        <ul>
          <li><a>INFO</a></li>
          <li><a>HTML</a></li>
          <li><a>CSS</a></li>
        </ul>
      </nav>
    </header>
    <main>
      <form method="post" action="https://freecodecamp.org/practice-project/accessibility-quiz">
        <section role="region" aria-labelledby="student-info">
          <h2 id="student-info">Student Info</h2>
        </section>
        <section role="region" aria-labelledby="html-questions">
          <h2 id="html-questions">HTML</h2>
        </section>
        <section role="region" aria-labelledby="css-questions">
          <h2 id="css-questions">CSS</h2>
        </section>
      </form>
    </main>
  </body>
</html>

/* file: styles.css */
body {
  background: #f5f6f7;
  color: #1b1b32;
  font-family: Helvetica;
  margin: 0;
}

header {
  width: 100%;
  height: 50px;
  background-color: #1b1b32;
  display: flex;
}

#logo {
  width: max(100px, 18vw);
  background-color: #0a0a23;
  aspect-ratio: 35 / 4;
  padding: 0.4rem;
}

h1 {
  color: #f1be32;
  font-size: min(5vw, 1.2em);
}

nav {
  width: 50%;
  max-width: 300px;
  height: 50px;
}

nav > ul {
  display: flex;
  justify-content: space-evenly;
}

h1,h2{
  font-family: Verdana;
  font-family: sans-serif;
  border-bottom: 4px solid #dfdfe2;

}

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36

Challenge: Learn Accessibility by Building a Quiz - Step 17

Link to the challenge:

just type the fall-back color right next to Verdana but with a space in the middle