title: setting white font color for dark background and V.S. in php
body: <p>while changing to dark background , I need to set the font color to white and exactly in opposite , when the background is bright so the font color should be black</p>
  
  <p>i don't the range to divide the dark and light colors in php </p>
  
  <p>my color codes are in hex format #ffffff</p>