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mystyle.scss

mystyle.css

mypage.html

$myFont: Helvetica, sans-serif;
$myColor: red;
$myFontSize: 18px;
$myWidth: 680px;

body {
  font-family: $myFont;
  font-size: $myFontSize;
  color: $myColor;
}

#container {
  width: $myWidth;
}

body {
  font-family: Helvetica, sans-serif;
  font-size: 18px;
  color: red;
}

#container {
  width: 680px;
  border: 1px blue double;
}

<!DOCTYPE html>
<html>
<link rel="stylesheet" href="mystyle.css">
<body>

<h1>Hello World</h1>

<p>This is a paragraph.</p>

<div id="container">This is some text inside a container.</div>

</body>
</html>