Problem with page margins when using @page:first rule

Hello,

I am trying to create a PDF file which has a kind of banner on the right side of the first page.

So i used the `@page`, `@page:first` and the `@right-top` rules to adjust the page margins and to insert the additional content:

```
@page {
size: A4 portrait;
margin: 10mm 5mm 15mm 20mm;
}

@page:first {
margin-right: 55mm;
@right-top {
padding: 1mm;
content: 'Some additional content\00000a@right-top\00000a(but only on the first page)';
white-space: pre;
vertical-align: top; text-align: left;
background: #ffeeee;
};
}
```
This works perfect for the first page, but on the follwing ones, the right margin defined in the `@page:first` rule is still used instead of the default value defined in the `@page` rule (by the way, similar effects arise when using the `@page:left` or `@page:right` rules).

For clarification please have a look at [Template.html.txt](https://github.com/danfickle/openhtmltopdf/files/1244710/Template.html.txt) and [Template.pdf](https://github.com/danfickle/openhtmltopdf/files/1244711/Template.pdf)

Thanks,
Bigdatha

Start by reproducing the issue with the attached Template.html.txt and compare the output with Template.pdf. Trace handling of the @page:first, @page:left, and @page:right rules, then verify that only the first page keeps its overridden right margin while later pages use the default @page margin.

Written by the indexing model from the issue text.