mystyle.scss
mystyle.css
mypage.html
 
@import "reset";

body {
  font-family: Helvetica, sans-serif;
  font-size: 18px;
  color: red;
}                  
html, body, ul, ol {
  margin: 0;
  padding: 0;
}

body {
  font-family: Helvetica, sans-serif;
  font-size: 18px;
  color: red;
}                  
<!DOCTYPE html>
<html>
<link rel="stylesheet" href="mystyle.css">
<body>

<h1>Hello World</h1>

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

<ul>
  <li><a href="#">HTML</a></li>
  <li><a href="#">CSS</a></li>
  <li><a href="#">SASS</a></li>
</ul>

</body>
</html>