モバイルファースト - header例

HTML記述例

<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width">
<title>Menu</title>
<link rel="stylesheet" href="css/menu.css">
</head>
<body>
<!-- .header -->
<header class="header">
  <div class="container">
    <h1 class="logo"><a href="#"><img src="img/logo.png" alt=""></a></h1>
    <nav class="gnav">
      <ul>
        <li><a href="index.html">ホーム</a></li>
        <li><a href="content.html">サービス案内</a></li>
        <li><a href="#">お問い合わせ</a></li>				
      </ul>
    </nav><!-- /.gnav -->
  </div><!-- /.container -->
</header>
<!-- /.header -->
</body>
</html>

CSS記述例

@charset "URF-8";

/* -------------------------------------------
  reset
------------------------------------------- */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
ul, li {
  list-style: none;
}
a {
  color: inherit;
  text-decoration: none;
}
img {
  max-width: 100%;
  vertical-align: bottom;
}


/* ------------------------------------------
  body
------------------------------------------- */
body {
  color: #333;
  font-size: 16px;
  font-family: 
    "Helvetica Neue",
    Arial,
    "Hiragino Kaku Gothic ProN",
    "Hiragino Sans",
    Meiryo,
    sans-serif;
  line-height: 1.0;
}


/* -------------------------------------------
  layout
------------------------------------------- */
.container {
  width: min(94%, 960px);
  margin: 0 auto;
  padding: 20px 0;
}
.logo {
  margin-bottom: 30px;
  text-align: center;
}
.gnav ul {
  display: flex;
  justify-content: center;
  gap: 40px;
}

@media screen and (min-width: 768px) {
  .header > .container {
    display: flex;
    align-items: center;
  }
  .logo {
    width: 134px;
    margin: 0 auto 0 0;
  }
}