QPushButton visual issue

I have two custom-styled QPushButton buttons. Here is the stylesheet for the Ok button:

QPushButton
{ 
    background-color:#9dce2c;
    border-radius:7px;
    border:1px solid #83c41a;
    color:#ffffff;
    font-size:15px;
    font-weight:bold;
    padding:4px 24px;
    text-decoration:none;
}
QPushButton:pressed
{
    border:2px solid black;
}

Now here's what it looks like:

which is fine. However, if the button is clicked (gets focus), it starts to look like this:

Note that slight shadowy rectangle around the text. It looks as if the text is being "selected". When the button loses focus, it starts looking normal again. I suppose it happens because the selected controls get highlighted like this:

However, I want my button to stay unchanged, no matter whether it's focused or not. Is there any way to solve this issue?