title: Property border-radius doesn't exist in CSS level 2.1 but exists in : 6px 6px
body: <p>I am new to web design and I have some problems in my website. 
  First, it is not a cross-browser compatible website. I want to make it so, but I don't know how to do this. I have read some articles about this, but they have not been any help. Please tell me how I can design a cross-browser website.</p>
  
  <p>Second, I have validated my website's CSS file and gotten these errors:</p>
  
  <p>218  .box    Property border-radius doesn't exist in CSS level 2.1 but exists in : 6px 6px
  219  .box    Property -moz-border-radius doesn't exist : 6px 6px
  220  .box    Property -webkit-border-radius doesn't exist : 6px 6px.</p>
  
  <p>But I don't know how to solve this either. </p>
  
  <p><a href="http://www.harvestcreativemedia.com" rel="nofollow">http://www.harvestcreativemedia.com</a></p>