使用媒体查询居中先前浮动的内容

Question

我正在尝试将问候 div 置于移动屏幕徽标正下方的中央。无论我做什么，它似乎都不起作用。问候只是一直停留在右边。我尝试添加和更改显示值、边距、填充，有和没有 bootstrap 列。没有任何效果 :( 请帮忙？

/* .....show borders for sizing.... 

* {
 border: 1px solid black;
}

*/

body {
 box-sizing: border-box;
 align-content: center;
}

.A {
 margin-top: 4%;
}

#logo {
 height: 100px;
 width: 220px;
 float: left;
}

#greet {
 float: right;
 padding-top: 1%;
 padding-left: 10%;
}

div#greet > h1 {
  line-height: .01em;
  font-family: 'Titillium Web', sans-serif;
  text-transform: uppercase;
  color: #3D3D3D;
}

div#greet > h2 {
 font-family: 'Muli', sans-serif;
 color: #3D3D3D;
}

.jumbotron {
    position: relative;
    width: 100%;
    max-height: 500;
    overflow: hidden;
    background-color: #FFFFFF !important;
    margin: 0 !important;
}

.hero {
 position: relative;
 width: 100%;
 height: 100%;
 overflow: hidden;
 margin: 0;
}

#zippity {
 text-align: center;
 text-transform: uppercase;
 font-family: 'Titillium Web', sans-serif;
 padding-bottom: 1.5%;
 color: #3D3D3D;
 margin: 0;
}

.dooda {
 display: inline;
 text-align: center;
}

#Pics {
 height: 60%;
 max-width: 100%;
 padding-top: 8%;
 padding-bottom: 8%;
}

#BB {
 border-top: 3px solid #0D4B6E;
 border-bottom: 6px solid #0D4B6E;
 padding-top: 2%;
 padding-bottom: 1%;
}

div#BB > h1 {
 text-transform: uppercase;
 font-family: 'Muli', sans-serif;
 font-size: 200%;
 line-height: .001em;
 color: #3D3D3D;
 letter-spacing: -.04em;
}

div#BB > h2 {
 text-transform: lowercase;
 font-family: 'Bilbo', cursive;
 font-size: 230%;
 line-height: .5em;
 color: #BB1F25;
 letter-spacing: .03em;
}

footer#copy {
 background-color: #3D3D3D !important;
}

p {
 color: white;
 text-align: center;
 font-family: 'Muli', sans-serif;
}

.sam {
 text-decoration: underline;
}

/* for mobile */

@media screen and (max-width: 570px) {

 div.A > #logo {
  display: block;
  text-align: center;
  float: none;
  height: 30%;
  width: 50%;
  margin-right: auto;
  margin-left: auto;
 }

 div.A > #greet > h1, div.A > #greet > h2 {
  float: none;
  text-align: center;
  margin-right: auto;
  margin-left: auto;
 }
}

<!DOCTYPE html>
<html>
<head>
 
 <meta charset="utf-8"/>
 <title>Hello, I’m Sam</title>
 <link rel="stylesheet" type="text/css" href="css.css"/>
 <link href="https://fonts.googleapis.com/css?family=Titillium+Web:600" rel="stylesheet">
 <link href="https://fonts.googleapis.com/css?family=Muli:300" rel="stylesheet">
 <link href="https://fonts.googleapis.com/css?family=Bilbo" rel="stylesheet">  
 <meta name="viewport" content="width=device-width, initial-scale=1"> 
 <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>

</head>
<body>

 <div class="container">
  <div class="A">
   <img id="logo" src="Images/Logo.png"/>
   <div id="greet">
    <h1>Hello, I'm Sam</h1>
    <h2>Web Designer</h2>
   </div>
  </div>
 </div>

 <img class="jumbotron hero" src="Images/hero1.jpg"/>

 <h1 id="zippity">Portfolio</h1>

 <div class="container">
  
  <div class="dooda row">

   <div class="tech col-md-4">
    <div id="BB">
     <h1>Technoline</h1>
     <h2>technoline.com</h2>
    </div>
    <img id="Pics" src="Images/technoline.jpg"/>
   </div>

   <div class="maj col-md-4">
    <div id="BB">
     <h1>Majestique</h1>
     <h2>majestique.com</h2>
    </div>
    <img id="Pics" src="Images/majestique.jpg"/>
   </div>

   <div class="sil col-md-4">
    <div id="BB">
     <h1>Silverzim</h1>
     <h2>silverzim.com</h2>
    </div>
    <img id="Pics" src="Images/silverzim.jpg"/>
   </div>

  </div>
 
 </div>

 <footer class="jumbotron" Id="copy">
  <p>&copy 2016 <span class="sam">Sam's Web Dev</span> All rights reserved</p>
 </footer>

</body>
</html>

Answer 1

#greet 具有 float 属性而不是 h1/h2。您在@media 代码中指的是 h1/h2 而不是更改 #greet 本身的浮点值。从@media 部分删除'> h1' 和'> h2'，这将得到你想要的。

Answer 2

清除 float 和 padding 并且有效：

#greet {float: none; padding-left: 0; }

/* .....show borders for sizing.... 

* {
 border: 1px solid black;
}

*/

body {
 box-sizing: border-box;
 align-content: center;
}

.A {
 margin-top: 4%;
}

#logo {
 height: 100px;
 width: 220px;
 float: left;
}

#greet {
 float: right;
 padding-top: 1%;
 padding-left: 10%;
}

div#greet > h1 {
  line-height: .01em;
  font-family: 'Titillium Web', sans-serif;
  text-transform: uppercase;
  color: #3D3D3D;
}

div#greet > h2 {
 font-family: 'Muli', sans-serif;
 color: #3D3D3D;
}

.jumbotron {
    position: relative;
    width: 100%;
    max-height: 500;
    overflow: hidden;
    background-color: #FFFFFF !important;
    margin: 0 !important;
}

.hero {
 position: relative;
 width: 100%;
 height: 100%;
 overflow: hidden;
 margin: 0;
}

#zippity {
 text-align: center;
 text-transform: uppercase;
 font-family: 'Titillium Web', sans-serif;
 padding-bottom: 1.5%;
 color: #3D3D3D;
 margin: 0;
}

.dooda {
 display: inline;
 text-align: center;
}

#Pics {
 height: 60%;
 max-width: 100%;
 padding-top: 8%;
 padding-bottom: 8%;
}

#BB {
 border-top: 3px solid #0D4B6E;
 border-bottom: 6px solid #0D4B6E;
 padding-top: 2%;
 padding-bottom: 1%;
}

div#BB > h1 {
 text-transform: uppercase;
 font-family: 'Muli', sans-serif;
 font-size: 200%;
 line-height: .001em;
 color: #3D3D3D;
 letter-spacing: -.04em;
}

div#BB > h2 {
 text-transform: lowercase;
 font-family: 'Bilbo', cursive;
 font-size: 230%;
 line-height: .5em;
 color: #BB1F25;
 letter-spacing: .03em;
}

footer#copy {
 background-color: #3D3D3D !important;
}

p {
 color: white;
 text-align: center;
 font-family: 'Muli', sans-serif;
}

.sam {
 text-decoration: underline;
}

/* for mobile */

@media screen and (max-width: 570px) {
    #greet {float: none; padding-left: 0; }
 div.A > #logo {
  display: block;
  text-align: center;
  float: none;
  height: 30%;
  width: 50%;
  margin-right: auto;
  margin-left: auto;
 }

 div.A > #greet > h1, div.A > #greet > h2 {
  float: none;
  text-align: center;
  margin-right: auto;
  margin-left: auto;
 }
}

<!DOCTYPE html>
<html>
<head>
 
 <meta charset="utf-8"/>
 <title>Hello, I’m Sam</title>
 <link rel="stylesheet" type="text/css" href="css.css"/>
 <link href="https://fonts.googleapis.com/css?family=Titillium+Web:600" rel="stylesheet">
 <link href="https://fonts.googleapis.com/css?family=Muli:300" rel="stylesheet">
 <link href="https://fonts.googleapis.com/css?family=Bilbo" rel="stylesheet">  
 <meta name="viewport" content="width=device-width, initial-scale=1"> 
 <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>

</head>
<body>

 <div class="container">
  <div class="A">
   <img id="logo" src="Images/Logo.png"/>
   <div id="greet">
    <h1>Hello, I'm Sam</h1>
    <h2>Web Designer</h2>
   </div>
  </div>
 </div>

 <img class="jumbotron hero" src="Images/hero1.jpg"/>

 <h1 id="zippity">Portfolio</h1>

 <div class="container">
  
  <div class="dooda row">

   <div class="tech col-md-4">
    <div id="BB">
     <h1>Technoline</h1>
     <h2>technoline.com</h2>
    </div>
    <img id="Pics" src="Images/technoline.jpg"/>
   </div>

   <div class="maj col-md-4">
    <div id="BB">
     <h1>Majestique</h1>
     <h2>majestique.com</h2>
    </div>
    <img id="Pics" src="Images/majestique.jpg"/>
   </div>

   <div class="sil col-md-4">
    <div id="BB">
     <h1>Silverzim</h1>
     <h2>silverzim.com</h2>
    </div>
    <img id="Pics" src="Images/silverzim.jpg"/>
   </div>

  </div>
 
 </div>

 <footer class="jumbotron" Id="copy">
  <p>&copy 2016 <span class="sam">Sam's Web Dev</span> All rights reserved</p>
 </footer>

</body>
</html>

使用媒体查询居中先前浮动的内容

center previously floated content using a media query

html

css

centering

media-queries