html - CSS float : Why doesn't the second box shift to the left side of my floated box

Question

我有以下 HTML 和 CSS。我想知道为什么第二个盒子不会浮到第一个盒子的一边。据我了解，如果 float 了特定宽度的框，则其他 div 将 float 到 float 框/div 的左侧，直到没有更多空间可容纳同一行框。

   #content-wrapper {
     border: 1px solid blue;
     width: 100%
   }
   .first-box {
     width: 450px;
     border: 1px solid red;
     float: left;
   }
   .first-box h2 {
     background: url(img/top-menu-bg.jpg) no-repeat;
     line-height: 45px;
     padding-left: 15px;
     margin-bottom: 15px;
   }
   .second-box {
     width: 5%;
     border: 1px solid red;
   }
   </style>

<div id="content-wrapper">
  <div class="first-box">
    <h2>Welcome to My Engg.</h2>
    <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It
      has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop
      publishing software like Aldus PageMaker including versions of Lorem Ipsum.</p>
  </div>
  <div class="second-box">
    <p>Some Side bar text</p>
  </div>
</div>

谢谢

Answer 1

需要设置display:inline-block

CSS

#content-wrapper{
  border:1px solid blue;
  width:100%;
  display:block;
  overflow:hidden;
}

.first-box {
  width:450px;
  border:1px solid red;
  float:left;
  display:inline-block;
}

.first-box h2{
  background:url(img/top-menu-bg.jpg) no-repeat;
  line-height:45px; 
  padding-left:15px; 
  margin-bottom:15px;
  display:inline-block;
 }

.second-box{
  width:5%;
  border:1px solid red;
  display:inline-block; //HERE YOUR FIX
 }

DEMO HERE