Different css loads for different browsers

Hi,
I edited some css for blocks.It works as i wanted in google chrome but when i browse through internet explorer or mozilla firefox then some additional css loads.
Heres what is happening

In google chrome the css is

element.style {
}

.marina-rounded-corners .inner-wrapper .inner-inner {
border: 1px solid lightgray;
padding: 8px;
}

Code (markup):

In mozilla the css is

element.style {
    border: medium none;
    position: relative;
}

.marina-rounded-corners .inner-wrapper .inner-inner {
  border: 1px solid lightgray;  ///// This line gets a strike through
padding: 8px;
}

Code (markup):

Because of this in mozilla and internet explorer the border doesn't show up.
Can anyone tell me how to fix it ?

Thanks.