<h1>display: flex;の場合の横並び</h1>

<nav>
  <ul>
    <li><a href="#">TOP</a></li>
    <li><a href="#">ABOUT</a></li>
    <li><a href="#">MAP</a></li>
    <li><a href="#">BLOG</a></li>
    <li><a href="#">CONTACT</a></li>
  </ul>
</nav>
nav ul {
  display:flex;
}

nav ul li {
  width: 100px;
  background-color: #dddddd;
  text-align: center;
  padding: 5px;
  list-style:none;
  margin:0 5px;
}

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