css - Media query isn't working -

This should be a very stupid question, but I can not find a media query to do this work. I can not change this when the size of the page changes.

stylesheet.css:

  font font-family: ubuntu; Src: url ('Ubuntu-L.T.TF'); } @ Font-faces {font-family: ubuntu; Src: url ("Ubuntu-BTF"); font-weight: bold; } Html, body {background-image: url ('bg2.png'); Repeat Background: Repeat; Background-attachment: fixed; Font-family: Ubuntu; Font-size: 48px; Margin: 0; Padding: 0; Text align: center; } # Menus {width: 900px; Height: 150px; Background: #FFF; Status: fixed; Left: 50%; Margin-left: -450px; Top: 50px; } # Content {width: 800px; Margin: 0 px auto; Padding-top: 100px; } .block {width: 100%; Height: 800 pixels; Margin-top: 100px; Margin-down: 100px; Boundary-radius: 5px; Background: #FFF; -Move box-shadow: 0 25 px 0 px rgba (0,0,0,0,5.5); Webkit-box-shadow: 0 25 px 0 px rgba (0,0,0,0,5.5); Box-shadow: 0 25 px 0 px rgba (0,0,0,0,5.5); } // media QUERY media screen and (max-width: 900px) {#content {width: 90%; } # Menus {width: 100%; Left: 0%; Top: 0%; Margin-left: 0 pixels; }}   
 index.html:  
  & lt; Html & gt; & Lt; Top & gt; & Lt; Link rel = "shortcut icon" href = "http://www.yellos.com/favi.ico" /> & Lt; Meta http-equiv = "content-type" content = "text / html; charset = UTF-8" /> & Lt; Meta name = "viewport" content = "width = device-width, initial-scale = 1.0" /> & Lt; Title & gt; Yellos & lt; / Title & gt; & Lt ;! - [If LT IE 9] & gt; & Lt; Script src = "http://css3-mediaqueries-js.googlecode.com/svn/trunk/css3-mediaqueries.js" & gt; & Lt; / Script & gt; & Lt; [Endif] - & gt; & Lt; Link rel = "stylesheet" type = "text / css" href = "stylesheet.css" /> & Lt; / Head & gt; & Lt; Body & gt; & Lt; Div id = "menu" & gt; ... & lt; / Div & gt; & Lt; Div id = "content" & gt; & Lt; Div class = "block" id = "1" & gt; Trial & lt; / Div & gt; & Lt; / Div & gt; & Lt; / Body & gt; & Lt; / Html & gt;   
 What am I doing?   
 
 
 The error is that the  //  comments in the CSS are not allowed.  
 Change  
  // media search   
  
  / * to search the media