UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36

Steps to reproduce the problem:
1. I use puppeteer @1.3.0 and chrome @65.0.3325.181
2. Generate PDF 

const puppeteer = require('puppeteer');

(async () => {
    const content = '<h1 style="font-size:20px;margin: 0;background: red">First <span style="background: yellow">second</span> third</h1>';

    const browser = await puppeteer.launch();
    const page = await browser.newPage();
    try {
        await page.setContent(content);
        await page.pdf({
            displayHeaderFooter: true,
            path: 'background_bug.pdf',
            printBackground: true,
            headerTemplate: content,
            margin: {
                top: '100px'
            }
        });
    } catch (e) {
        console.error(`Something went wrong: ${e.message}`);
    } finally {
        await browser.close();
    }
})();

What is the expected behavior?
The background color should be rendered in a header.

What went wrong?
The background color is not rendered in a header.

Did this work before? No 

Chrome version: 65.0.3325.181  Channel: n/a
OS Version: OS X 10.13.3
Flash Version:
 

Deleted: background_bug.pdf 46.9 KB

background_bug.pdf 46.9 KB Download

Deleted: Screen.png 23.9 KB

	Screen.png 23.9 KB View Download