背景：网址和过滤器：亮度

Question

我想用 filter:brightness 使 div 的背景图像变暗。它运作良好，但显然它会使整个 div 变暗，而不仅仅是图像。如何使用 CSS 仅使背景图像变暗？我想在上面写一些白色的文字。

这是我的代码：

#about_header {
  background: url(../img/background/spa_02.jpg) no-repeat center center fixed;
 filter: brightness(20%);
 -webkit-filter: brightness(20%);
 -moz-filter: brightness(20%);
 -o-filter: brightness(20%);
 -ms-filter: brightness(20%);
  height:400px;
  display: table;
  position: relative;
  width: 100%;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}

#about_header h1{
  color: white;
}

<section id="about_header">
  <div class="container text-vcenter">
    <div class="row">
      <div class="col-sm-12">
        <div>
          <h1>Contact us</h1>
        </div>
      </div>
    </div>
  </div>
</section>

Answer 1

当我谈到父母和孩子时，我实际上是错的。您必须将容器放在同一级别：

#about_header {
  background: url("http://www.thestatedhome.com/media/catalog/category/13514044-brown-natural-linen-texture-for-the-background-Stock-Photo.jpg") no-repeat center center fixed;
  filter: brightness(20%);
  height: 400px;
  position: relative;
  width: 100%;
  background-size: cover;
}

.container {
  display: table;
  position: absolute;
  top: 0px;
  height: 400px;
  width: 100%;
}

.text-vcenter {
  display: table-cell;
  text-align: center;
  vertical-align: middle;
}

.container h1 {
  color: white;
}

<section id="about_header"></section>
<div class="container">
  <div class="text-vcenter">
    <div class="row">
      <div class="col-sm-12">
        <div>
          <h1>Contact us</h1>
        </div>
      </div>
    </div>
  </div>
</div>