improvement for better grade in Google Chrome audit

[adren]

Google Chrome provides an audit function, which runs a series of tests with recommendations
some are probably inefficient, while others are quite useful and easy to implement

on Google Chrome 65 (with new audit tests), here are the following results:

• Performance 91
• Progressive Web App 55
• Accessibility 82
• Best Practices 88
• SEO 78

[denysvitali]

Thanks for the issue! I'll look into it in the following days 🚀