My test.html:

```
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<link rel="stylesheet" type="text/css" href="test.css" />
<title>test</title>
</head>
<body>
    <div id="header">header</div>

    <div id="container">
      <h1>content</h1>
      <p>test</p>
      <p class="last">...</p>
    </div>

    <div id="sidebar">
      <h1>sidebar</h1>
      <ul>
        <li>link one</li>
        <li>link two</li>
      </ul>
    </div>

    <div id="footer">footer</div>
</body>
</html>

```

my test.css:

```
@CHARSET "ISO-8859-1";
#header {
  background: #d7dabd;
}
#container {
  width: 100%;
  float: right;
  margin-left: -200px;
}
#sidebar {
  width: 200px;
  float: left;
}
#footer {
  background: #d7dabd;
  clear: both; 
}

```

The final effect is:
![enter image description here](https://i.stack.imgur.com/NgRwp.png)

I expect #sidebar on the left and #container on the right of the page. but they are mixed in the left