#page a {color: blue;}
a {color: green;}

#page a.prev { color: green; }

.nav-links > a { color: green; }

.nav-links > a.prev { color: green; }

<div id="page">
  <nav class="navigation pagination" role="navigation">
    <h2 class="screen-reader-text">Posts navigation</h2>
    <div class="nav-links">
      <a class="prev page-numbers" href="#">Prev</a>
      <a class='page-numbers' href='#'>1</a>
      <span aria-current='page' class='page-numbers current'>2</span>
    </div>
  </nav>
</div>