I'm using puppeteer-core with chrome-aws-lambda in a Firebase Cloud Function to scrape a webpage and apply a custom font. However, despite injecting the @font-face rule via page.addStyleTag, the font is not applied in the generated screenshot.

const scraper = async (url: string) => {
    let browser;

    try {
        browser = await puppeteer.launch({
            args: ["--no-sandbox", "--disable-web-security"],
            executablePath: await chromium.executablePath,
            headless: chromium.headless,
        });

        const page = await browser.newPage();

        // Set user agent and viewport for mobile
        await page.setUserAgent(
            "Mozilla/5.0 (Linux; Android 11; Pixel 5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Mobile Safari/537.36"
        );
        await page.setViewport({ width: 390, height: 844, deviceScaleFactor: 3 });

        await page.goto(url, { waitUntil: "domcontentloaded" });
        await page.waitForTimeout(5000); // Ensure the font has time to load

        // Load custom font
        const fontPath = path.join(__dirname, "..", "fonts", "Vazirmatn-Regular.ttf");
        const fontBuffer = fs.readFileSync(fontPath);
        const fontBase64 = fontBuffer.toString("base64");
        const fontDataUrl = `data:font/ttf;base64,${fontBase64}`;

        // Inject font into the page
        await page.addStyleTag({
            content: `
                @font-face {
                    font-family: 'Vazirmatn';
                    src: url(${fontDataUrl}) format('truetype');
                }
                * {
                    font-family: 'Vazirmatn', sans-serif !important;
                    font-size: 24px;
                }
            `,
        });

        // Capture screenshot or evaluate page styles
        await page.screenshot({ path: "output.png", fullPage: true });

    } catch (error) {
        console.error("Error scraping website:", error);
        throw new Error("Failed to scrape website");
    } finally {
        if (browser) {
            await browser.close();
        }
    }
};