W3School TIY Editor

<!DOCTYPE html>
<html>
<head>
<style> 
html {
  font-size: small;
  color: blue;
}

#ex1 {
  background-color: yellow;
  color: red;
}

#ex2 {
  background-color: yellow;
  color: red;
  all: inherit;
}

#ex3 {
  background-color: yellow;
  color: red;
  all: initial;
}

#ex4 {
  background-color: yellow;
  color: red;
  all: unset;
}
</style>
</head>
<body>

<p>未设置 all 属性：</p>
<div id="ex1">Shanghai is one of the four direct-administered municipalities of the People's Republic of China. Welcome to Shanghai!</div>

<p>all: inherit:</p>
<div id="ex2">Shanghai is one of the four direct-administered municipalities of the People's Republic of China. Welcome to Shanghai!</div>

<p>all: initial:</p>
<div id="ex3">Shanghai is one of the four direct-administered municipalities of the People's Republic of China. Welcome to Shanghai!</div>

<p>all: unset:</p>
<div id="ex4">Shanghai is one of the four direct-administered municipalities of the People's Republic of China. Welcome to Shanghai!</div>

</body>
</html>