CSS Clear Float 不适用于媒体查询

Question

我正在尝试清除两个元素的浮动，但它不起作用，我也不知道为什么。答案大概就在我眼前。
clear前可能跟我的Media Queries或者其他风格有关系。 clear 本身甚至可能有效，但 float 属性无效。
这是我风格中的两个元素 sheet：

/* main navigation on small screens like smartphones */

#main_nav {
  position: sticky;
  top: 0;
  text-align: center;
  box-shadow: 0 0 1.563rem 0;
}

#main_nav ul {
  margin: 0;
  padding: 0;
  background-color: #1f1f14;
  border-top: 0.0625rem solid #faf352;
}

#main_nav ul li {
  list-style-type: none;
  display: inline-block;
  margin: 0.625rem 0;
  width: 22%;
  padding: 0;
  text-align: center;
}

#main_nav ul li a {
  padding: 0.2rem;
  color: #D7D7CF;
  font-family: 'Finger Paint';
  font-size: 0.7rem;
  text-decoration: none;
}


/* main container on small screens */

main {
  padding: 0.2rem 0.5rem 0 0.5rem;
}


/* large desktop screens - more than 1000px width */

@media screen and (min-width: 62.500em) {
  #main_nav {
    position: static;
    float: left;
    width: 20%;
    padding: 1rem;
    box-shadow: none;
  }
  #main_nav ul li {
    width: 100%;
    padding: 0.5rem;
    display: block;
  }
  #main_nav ul li a {
    display: inline-block;
    width: 90%;
    font-size: 0.9rem;
    margin: 0.2rem;
    padding: 0.3rem;
  }
  main {
    width: 95%;
    float: left;
    padding: 0 1rem;
  }
  /* clear float */
  .cf:before,
  .cf:after {
    content: "";
    display: table;
    display: block;
  }
  .cf:after {
    clear: both;
  }
}


}

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>page title</title>
  <link href="mystyles.css" rel="stylesheet" type="text/css">
</head>

<body>
  <div id="holder">

    <header id="page_header">
      <h1><span class="yellow">This is</span> a heading</h1>
    </header>

    <nav id="main_nav" class="cf">
      <ul>
        <li><a href="#">link one</a></li>
        <li><a href="#">link two</a></li>
        <li><a href="#">link three</a></li>
        <li><a href="#">link four</a></li>
      </ul>
    </nav>

    <main class="cf">
      <section>
        <article>
          <h3>This is an awesome heading</h3>
          <p>text</p>
          <img src="images/st-color-300px.jpg" alt="picture">
          <p>text</p>
        </article>
      </section>
    </main>
  </div>
</body>

</html>

Answer 1

在容器而不是浮动元素上应用您的 clearfix。在这里你应该在 #holder 上应用 clearfix（虽然我建议添加一个 class 并定位它而不是一个 id，我在这里使用 container）。

/* main navigation on small screens like smartphones */

#main_nav {
  position: sticky;
  top: 0;
  text-align: center;
  box-shadow: 0 0 1.563rem 0;
}

#main_nav ul {
  margin: 0;
  padding: 0;
  background-color: #1f1f14;
  border-top: 0.0625rem solid #faf352;
}

#main_nav ul li {
  list-style-type: none;
  display: inline-block;
  margin: 0.625rem 0;
  width: 22%;
  padding: 0;
  text-align: center;
}

#main_nav ul li a {
  padding: 0.2rem;
  color: #D7D7CF;
  font-family: 'Finger Paint';
  font-size: 0.7rem;
  text-decoration: none;
}


/* main container on small screens */

main {
  padding: 0.2rem 0.5rem 0 0.5rem;
}

/* large desktop screens - more than 1000px width */

@media screen and (min-width: 62.500em) {

  #main_nav {
    position: static;
    float: left;
    width: 20%;
    padding: 1rem;
    box-shadow: none;
  }

  #main_nav ul li {
    width: 100%;
    padding: 0.5rem;
    display: block;
  }

  #main_nav ul li a {
    display: inline-block;
    width: 90%;
    font-size: 0.9rem;
    margin: 0.2rem;
    padding: 0.3rem;
  }

  main {
    width: 95%;
    float: left;
    padding: 0 1rem;
  }

  /* clear float */

  .container:after {
    content: "";
    display: table;
    clear: both;
  }
}

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>page title</title>
  <link href="mystyles.css" rel="stylesheet" type="text/css">
</head>

<body>
  <div id="holder" class="container">

    <header id="page_header">
      <h1><span class="yellow">This is</span> a heading</h1>
    </header>

    <nav id="main_nav" class="cf">
      <ul>
        <li><a href="#">link one</a></li>
        <li><a href="#">link two</a></li>
        <li><a href="#">link three</a></li>
        <li><a href="#">link four</a></li>
      </ul>
    </nav>

    <main class="cf">
      <section>
        <article>
          <h3>This is an awesome heading</h3>
          <p>text</p>
          <img src="images/st-color-300px.jpg" alt="picture">
          <p>text</p>
        </article>
      </section>
    </main>
  </div>
</body>

</html>

CSS Clear Float 不适用于媒体查询

CSS Clear Float not working with Media Queries

html

css

media-queries

css-float

clearfix