I would love to know, to optimize your website for Tablets, desktops and smarthpones, what is best to use: Media Queries or the Viewport meta tags? see code:
Both are necessary.
Media queries are used to have different css for different devices its like the if condition for different devices.
Viewport meta tag is to set tell the device to take the width according to this tag. Its like a reset for devices if its not used device will adjust the layout according to its default settings.