CSS 中带有伪元素的背景图片

Question

我得到了以下代码：

.container {
  color: white;
  height: 80vh;
  margin: 10vh 0 0 25vw;
  position: relative;
  width: 50vw;
}

.container::after {
  content: "";
  background: url('https://i.ibb.co/ngx7VSR/photo-2021-04-19-21-24-36.jpg');
  background-position: center;
  background-size: cover;
  filter: brightness(.5);
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  z-index: -1;
}

.container_inside {
  align-items: center;
  display: flex;
  flex-direction: column;
  font-size: 1.5em;
  height: calc(100% - 4em);
  justify-content: center;
  padding: 2em;
  text-align: center;
  width: calc(100% - 4em);
}

.small {
  color: #e9e9e9;
  font-size: .7em;
}

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>The background</title>
</head>
<body>
<div class="container">
  <div class="container_inside">
    <p>Any fool can write code that a computer can understand. Good programmers write code that humans can
      understand.</p>
    <p class="small">Martin Fowler</p>
  </div>
</div>
</body>
</html>

这里有两个目标：

使用 ::after 而不是 ::before
CSS 某处缺少一行代码，它的缺失毁了一切。将缺失的属性添加到正确的位置，使其看起来符合预期。

我找到了缺失的代码行 (content: "";)，并将 ::before 替换为 ::after，这是我得到的地方：

.container::after {
  content: "";
  background: url('https://i.ibb.co/ngx7VSR/photo-2021-04-19-21-24-36.jpg');
  background-position: center;
  background-size: cover;
  filter: brightness(.5);
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  z-index: -1;
}

我正在努力让背景图像扩展到它的全尺寸，否则任务就解决了。代码编辑器告诉我任务 2 是正确的，但由于某种原因任务 1 未被接受，我认为它与图像大小有关，但我可能错了。

理想情况下它应该是这样的：https://ucarecdn.com/d24c1329-c0a3-4bd6-948c-5cfd83466c86/

非常感谢对此的任何帮助！

Answer 1

尝试使用这个，.container {width: 50vw;}

.container::after {
  content: '';
  background: url('https://i.ibb.co/ngx7VSR/photo-2021-04-19-21-24-36.jpg');
  background-position: center;
  background-size: cover;
  filter: brightness(0.5);
  position: absolute;
  top: 50%; /* changed */
  left: 50%; /* changed */
  bottom: 0; /* added */
  right: 0; /* added */
  width: 100vw; /* changed */
  height: 100vh; /* changed */
  transform: translate(-50%, -50%); /* added */
  z-index: -1;
}

结果：

* {
  margin: 0; /* added */
  padding: 0; /* added */
  box-sizing: border-box; /* added */
}

.container {
  color: white;
  height: 80vh;
  margin: 10vh 0 0 25vw;
  position: relative;
  width: 50vw;
}

.container::after {
  content: '';
  background: url('https://i.ibb.co/ngx7VSR/photo-2021-04-19-21-24-36.jpg');
  background-position: center;
  background-size: cover;
  filter: brightness(0.5);
  position: absolute;
  top: 50%; /* changed */
  left: 50%; /* changed */
  bottom: 0; /* added */
  right: 0; /* added */
  width: calc(100vw - 30px); /* changed 3 times */
  height: calc(100vh - 30px); /* changed 2 times */
  transform: translate(-50%, -50%); /* added */
  z-index: -1;
}

.container_inside {
  align-items: center;
  display: flex;
  flex-direction: column;
  font-size: 1.5em;
  height: 100%; /* changed */
  justify-content: center;
  padding: 2em;
  text-align: center;
  width: 100%; /* changed */
}

.small {
  color: #e9e9e9;
  font-size: 0.7em;
}

<div class="container">
  <div class="container_inside">
    <p>Any fool can write code that a computer can understand. Good programmers write code that humans can understand.</p>
    <p class="small">Martin Fowler</p>
  </div>
</div>

Answer 2

正如 Mihai T 指出的那样，问题出在 width 上。我只是从第一个容器中删除了 width，它解决了问题。

最终解决方案

.container {
  color: white;
  height: 80vh;
  margin: 10vh 0 0 25vw;
  position: relative;
}

.container::after {
  content: "";
  background: url('https://i.ibb.co/ngx7VSR/photo-2021-04-19-21-24-36.jpg');
  background-position: center;
  background-size: cover;
  filter: brightness(.5);
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
}

.container_inside {
  align-items: center;
  display: flex;
  flex-direction: column;
  font-size: 1.5em;
  height: calc(100% - 4em);
  justify-content: center;
  padding: 2em;
  text-align: center;
  width: calc(100% - 4em);
}

.small {
  color: #e9e9e9;
  font-size: .7em;
}

<div class="container">
  <div class="container_inside">
    <p>Any fool can write code that a computer can understand. Good programmers write code that humans can understand.</p>
    <p class="small">Martin Fowler</p>
  </div>
</div>

CSS 中带有伪元素的背景图片

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