肆壹玖

HTML

兩個div區塊，利用相對、絕對位置固定

<div class="icon-box position-relative"></div>

<div class="col-12 position-absolute title-bg">
      <div class="title-bg-color"></div>
 </div>

 

CSS 

#section3 .box {
      position: relative;
}


#section3 .title-bg-color {
    position: absolute;
    top: 0px;
    background-color: #EFEFEF;
    height: 35px;
    width: -webkit-fill-available;
}