html结构中——左右两个盒子；
    左边固定宽度，右侧宽度100%；
    为左侧盒子设置position:absolute;
    右侧盒子添加子盒，设置padding-left，属性值为左侧盒子的宽度

示例1 

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>自适应两栏布局</title>
    <style type="text/css">
      .box1 {
        width: 200px;
        height: 200px;
        background-color: red;

        float: left;
      }

      .box2 {
        /* width: 200px; */
        height: 200px;
        background-color: yellow;
        overflow: hidden;
        /* float: left; */
      }
    </style>
  </head>
  <body>
    <div class="box1"></div>
    <div class="box2"></div>
  </body>
</html>

html-自适应两栏布局--小技巧_固定宽度

示例2、

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>自适应布局</title>
    <style type="text/css">
      .box1{
        position: absolute;

        width: 200px;
        min-height: 200px;
        background-color: #00498B;
      }
      .box2{
        width: 100%;
        min-height: 200px;
        background-color: #008000;
      }
      .box{
        padding-left: 200px;
      }
    </style>
  </head>
  <body>
    <div class="box1">left</div>
    <div class="box2">
      <div class="box">right</div>
    </div>
  </body>
</html>

html-自适应两栏布局--小技巧_自适应两栏布局_02