title: How to change font size (in percent) of QLabel widget using setStyleSheet?
body: <p>I am looking for a simple way to make a larger text size for a title label in my PySide2 app. This is a learning project. I prefer to use a style sheet to change the label font. I also do not wish to use hard coded point sizes because that may not work well on different display sizes.</p>
  
  <p>This other <a href="https://stackoverflow.com/questions/40861305/dynamically-change-font-size-of-qlabel-to-fit-available-space">question</a> looks interesting, but it is too complex for me at this time. Is there a simple way to make a larger font, such as <code>font-size: 200%</code>? I tried exactly that and so far it is not working. </p>
  
  <p>When I use a %, the font size does not change at all. When I set a specific size such as <code>font-size: 20px</code> it produces the expected results. </p>
  
  <p>I'm not finding the Qt docs to be of much help (probably because I don't know my way around them yet.) Here's my code:</p>
  
  <pre><code>from PySide2 import QtWidgets
  from PySide2.QtCore import Qt
  
  class MyWidget(QtWidgets.QWidget):
  
      def __init__(self, parent=None):
  
          super(MyWidget, self).__init__(parent)
          mainLayout = QtWidgets.QVBoxLayout(self)
          self.label = QtWidgets.QLabel("My Title")
          self.label.setAlignment(Qt.AlignCenter | Qt.AlignHCenter)
          self.label.setStyleSheet("font-weight: bold; font-size: 200%")
          mainLayout.addWidget(self.label)
  </code></pre>