左侧固定，右侧自适应的布局方式(新增评论区大佬教的方法）

一.浮动布局

1.先让固定宽度的div浮动！使其脱离文档流。
2.margin-left的值等于固定div的宽度相等。

   .aside{
        float: left;
        width: 200px;
        background-color: red;
    }
    .content{
        margin-left: 200px;
        background-color: blue;
    }
    
<div class="aside">
    Lorem ipsum dolor sit amet, consectetur adipisicing elit. Labore provident dolor in voluptatum tempore non, placeat obcaecati totam ut delectus libero excepturi distinctio asperiores odit nobis soluta, esse aspernatur beatae.
</div>
<div class="content">
    Lorem ipsum dolor sit amet, consectetur adipisicing elit. Labore provident dolor in voluptatum tempore non, placeat obcaecati totam ut delectus libero excepturi distinctio asperiores odit nobis soluta, esse aspernatur beatae.
</div>

二.margin的负值(3个div)

1. 是固定宽度的div脱离文档流。
2. 利用marin负值可以使得，后面的div可以与前面的div 保持同行显示。

3. 给包裹内容的div加margin-left 可以使得与左边的文字不重叠

   .aside{
       float: left;
       margin-right: -200px;
       width: 200px;
       background-color: red;
   }
   .content{
       float: right;
   }
   .content .inner{
       margin-left: 200px;
       background-color: blue;
   }
   
    <div class="aside">
      Lorem ipsum dolor sit amet, consectetur adipisicing elit. Labore provident dolor in voluptatum tempore non, placeat obcaecati totam ut delectus libero excepturi distinctio asperiores odit nobis soluta, esse aspernatur beatae.
   </div>
   <div class="content">
      <div class="inner">
         Lorem ipsum dolor sit amet, consectetur adipisicing elit. Labore provident dolor in voluptatum tempore non, placeat obcaecati totam ut delectus libero excepturi distinctio asperiores odit nobis soluta, esse aspernatur beatae.
      </div> 
   

   </div>

三.calc()计算属性

注意：使用calc计算属性的时候 运算符(- +等等)两边必须有空格

1. 注意两个div必须一左一右浮动。

2. calc的宽度必须要减去的宽度要与固定宽度保持一致。

     .aside{
         float: left;
         width: 200px;
         background-color: red;
     }
     .content{
         calc:(100% - 200px);
         background-color: blue;
     }
   

   <div class="aside">

     Lorem ipsum dolor sit amet, consectetur adipisicing elit. Labore provident dolor in voluptatum tempore non, placeat obcaecati totam ut delectus libero excepturi distinctio asperiores odit nobis soluta, esse aspernatur beatae.
      </div>
    <div class="content">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit. Labore provident dolor in voluptatum tempore non, placeat obcaecati totam ut delectus libero excepturi distinctio asperiores odit nobis soluta, esse aspernatur beatae.        
     </div>
   
   

四.flex布局

1. 需要给父级div设置display: flex属性。
2. 固定宽度的div设置flex: 0 0 200px即可。

3. 内容区域的div直接写出flex: 1即可。

   .container{
       display: flex;
   }
   .aside{
       flex: 0 0 200px;
       background-color: red; 
   }
   .content{
       flex: 1;
       background-color: blue;
   }
   <div class="container">
       <div class="aside">
       Lorem ipsum dolor sit amet, consectetur adipisicing elit. Labore provident dolor in voluptatum tempore non, placeat obcaecati totam ut delectus libero excepturi distinctio asperiores odit nobis soluta, esse aspernatur beatae.
       </div>
       <div class="content">
       Lorem ipsum dolor sit amet, consectetur adipisicing elit. Labore provident dolor in voluptatum tempore non, placeat obcaecati totam ut delectus libero excepturi distinctio asperiores odit nobis soluta, esse aspernatur beatae.
       </div>
   </div>
   
   

五.左侧浮动，右侧overflow:hidden

.aside{
    width: 200px;
    float: left;
    background-color: red;
}
.content{
    overflow: hidden;
    background-color: blue;
}
<div class="aside">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit. Labore provident dolor in voluptatum tempore non, placeat obcaecati totam ut delectus libero excepturi distinctio asperiores odit nobis soluta, esse aspernatur beatae.
    </div>
    <div class="content">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit. Labore provident dolor in voluptatum tempore non, placeat obcaecati totam ut delectus libero excepturi distinctio asperiores odit nobis soluta, esse aspernatur beatae.
    </div>

阮一峰老师写的教程权威传送门：http://www.ruanyifeng.com/blo...

原文地址：https://segmentfault.com/a/1190000016694777