title: CSS selector notation
body: <p>maybe a silly question but as far as I like standards I'd like to know, how should we write CSS selectors:</p>
  
  <ol>
  <li>.my-selector-for-div (breaks)</li>
  <li>.mySelectorForDiv (camel case)</li>
  </ol>
  
  <p>Is there a standard which of those ( or any other ) should be used ? </p>