Footer: Big

<footer class="usa-footer usa-footer-big" role="contentinfo">
    <div class="usa-grid usa-footer-return-to-top">
        <a href="#">Return to top</a>
    </div>
    <div class="usa-footer-primary-section">
        <div class="usa-grid">
            <nav class="usa-footer-nav usa-width-two-thirds">
                <ul class="usa-unstyled-list usa-width-one-fourth usa-footer-primary-content">
                    <li class="usa-footer-primary-link">
                        <h4>Topic</h4>
                    </li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link that's a bit longer than most of the others</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                </ul>
                <ul class="usa-unstyled-list usa-width-one-fourth usa-footer-primary-content">
                    <li class="usa-footer-primary-link">
                        <h4>Topic</h4>
                    </li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link that's pretty long</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                </ul>
                <ul class="usa-unstyled-list usa-width-one-fourth usa-footer-primary-content">
                    <li class="usa-footer-primary-link">
                        <h4>Topic</h4>
                    </li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                </ul>
                <ul class="usa-unstyled-list usa-width-one-fourth usa-footer-primary-content">
                    <li class="usa-footer-primary-link">
                        <h4>Topic</h4>
                    </li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                    <li class="usa-footer-secondary-link"><a href="javascript:void(0);">Secondary link</a></li>
                </ul>
            </nav>

            <div class="usa-sign_up-block usa-width-one-third">
                <h3 class="usa-sign_up-header">Sign up</h3>

                <label class="" for="email" id="">Your email address</label>
                <input id="email" name="email" type="email">

                <button type="submit">Sign up</button>
            </div>
        </div>
    </div>

    <div class="usa-footer-secondary_section usa-footer-big-secondary-section">
        <div class="usa-grid">
            <div class="usa-footer-logo usa-width-one-half">
                <img class="usa-footer-big-logo-img" src="../../dist/img/logo-img.png" alt="">
                <h3 class="usa-footer-big-logo-heading">Name of Agency</h3>
            </div>
            <div class="usa-footer-contact-links usa-width-one-half">
                <a class="usa-link-facebook" href="javascript:void(0);">
          <span>Facebook</span>
        </a>
                <a class="usa-link-twitter" href="javascript:void(0);">
          <span>Twitter</span>
        </a>
                <a class="usa-link-youtube" href="javascript:void(0);">
          <span>YouTube</span>
        </a>
                <a class="usa-link-rss" href="javascript:void(0);">
          <span>RSS</span>
        </a>
                <h3 class="usa-footer-contact-heading">Agency Contact Center</h3>
                <address>
          <div class="usa-footer-primary-content usa-footer-contact_info">
            <p>
              <a href="tel:1-800-555-5555">(800) CALL-GOVT</a>
            </p>
          </div>
          <div class="usa-footer-primary-content usa-footer-contact_info">
            <p><a href="mailto:info@agency.gov">info@agency.gov</a></p>
          </div>
        </address>
            </div>
        </div>
    </div>
</footer>