Good on my iphone but not on the clients

She has a different size phone than you or I do. So it’s not just her phone but anyone that has a similar size phone.

Unfortunately, there are so many phone sizes out there that it’s difficult to design layouts to cover them all.

What I suggest is that you open your desktop browser and resize the window and see what the pages look like at or about each breakpoint.

Here’s a post that gives you some ideas for the RW breakpoints, of course this can vary from stack to stack and from theme or framework.

Here’s a list of the common device viewport sizes. The CSS width column is the one that you can use.