Nested named pages causes infinity loop
```html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>invalid-nested-named-pages.html</title>
<style>
@page {
size: 200px 100px;
margin: 10px;
}
@page salmon {
background: lightsalmon;
}
@page lavender {
background: lavender;
}
html {
font-size: 10px;
line-height: 10px;
color: black;
}
.lavender {
page: lavender;
}
.salmon {
page: salmon;
}
</style>
</head>
<body>
<article>
<div>Here goes some content on a normal page</div>
<div class="lavender">
<div class="salmon">I should be on a salmon page</div>
</div>
<div>And back to normal</div>
</article>
</body>
</html>
```
issue