I have a Galaxy S7. When you go into developer tools and Toggle Device Toolbar, NONE of the sites for any device are remotely similar to what I see when I bring that site up on my cell phone.
And, I get that I have a Galaxy S7 and I'm using the S5 viewer in Dev Tools. But, it's not even close! I remember this also being the case when I had my Nexus 5. Some sites look okay... like Yahoo and CNN look the same on my cell phone as they do in Dev Tools. But like, the site I'm working on is HillPicks.com. What I see on Dev Tools for that site looks NOTHING like what I see on my cell phone. Why is that?