Responsive button ionic 2

Hello,
I am trying to make the buttons on my page responsive with multiple screen. I follow many suggestions but they doesn’t work like “responsive-sm”

button{
background-color: white;
border: 0.063rem solid black;
color: dodgerblue;
padding: 10.000rem 10.000rem;
text-align: center;
text-decoration: none;
display: inline-block;
font-size: 2.000rem;
}

button on ipad .image

buttons on iphone 6
image

how can i resolve this situation.
thank you in advance