title: at-rules not working in visual studio
body: <p>So I'm using code from this link:
  <a href="http://thecodeplayer.com/walkthrough/pure-css3-animated-clouds-background" rel="nofollow noreferrer">http://thecodeplayer.com/walkthrough/pure-css3-animated-clouds-background</a></p>
  
  <p>Which contains:</p>
  
  <pre><code>@-webkit-keyframes moveclouds {
  0% {margin-left: 1000px;}
  100% {margin-left: -1000px;}
  }
  @-moz-keyframes moveclouds {
  0% {margin-left: 1000px;}
  100% {margin-left: -1000px;}
  }
  @-o-keyframes moveclouds {
  0% {margin-left: 1000px;}
  100% {margin-left: -1000px;}
  }
  </code></pre>
  
  <p>And it's causing this error:</p>
  
  <p><a href="https://i.stack.imgur.com/X2O7o.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/X2O7o.png" alt="Error"></a></p>
  
  <hr>
  
  <blockquote>
    <p>"Parser Error</p>
    
    <p>Description: An error occurred during the parsing of a resource
    required to service this request. Please review the following specific
    parse error details and modify your source file appropriately. </p>
    
    <p>Parser Error Message: "-" is not valid at the start of a code block. 
    Only identifiers, keywords, comments, "(" and "{" are valid.</p>
    
    <p>Source Error: </p>
    
    <p>Line 185:    } Line 186: Line 187:    @-o-keyframes moveclouds { Line
    188:        0% { Line 189:            margin-left: 1000px;"</p>
  </blockquote>
  
  <p>If I remove the "at-rules" it'll work just fine; however, the clouds won't move.</p>