设置 QPushButton 样式及点击时 QPushButton:pressed 的样式

button.setStyleSheet(''' 
                     QPushButton
                     {text-align : center;
                     background-color : white;
                     font: bold;
                     border-color: gray;
                     border-width: 2px;
                     border-radius: 10px;
                     padding: 6px;
                     height : 14px;
                     border-style: outset;
                     font : 14px;}
                     QPushButton:pressed
                     {text-align : center;
                     background-color : light gray;
                     font: bold;
                     border-color: gray;
                     border-width: 2px;
                     border-radius: 10px;
                     padding: 6px;
                     height : 14px;
                     border-style: outset;