圣杯/双飞翼布局与负边距

左右定宽，中间自适应，利用负边距来改变文档流

圣杯布局

<div class="content">
  <div class="middle"></div>
  <div class="left"></div>
  <div class="right"></div>
</div>

.content {
  overflow: hidden;
  padding: 0 100px;
}

.middle {
  position: relative;
  width: 100%;
  float: left;
  height: 80px;
  background: #f00;
}

.left {
  position: relative;
  width: 100px;
  float: left;
  left: -100px;
  height: 80px;
  margin-left: -100%;
  background: #0f0;
}

.right {
  position: relative;
  width: 100px;
  float: left;
  right: -100px;
  height: 80px;
  margin-left: -100px;
  background: #00f;
}

双飞翼布局

    <div class="content">
        <div class="middle">
            <div class="inner-middle"></div>
        </div>
        <div class="left"></div>
        <div class="right"></div>
    </div>

        .content {
            overflow: hidden;
        }

        .middle {			
            width: 100%;
            float: left;
        }
               .inner-middle{
            width:100%;
            height: 80px;
            
            background: green;			
        }
        .left {
            width: 100px;
            float: left;
            height: 80px;
            margin-left: -100%;
            background: yellow;
        }

        .right {			
            width: 100px;
            float: left;
            height: 80px;
            margin-left: -100px;
            background: pink
        }