title: how to protect css files like this site
body: <p>I use <a href="http://www.font-api.ir" rel="nofollow noreferrer">this site</a> for web font. (This is a web font provider like google fonts)
  I need protect my css and js file like this site.</p>
  
  <p>when you see below html file this css load complete and page show correctly but you don't access css files.</p>
  
  <p>What method this site uses for securing css files??</p>
  
  <pre><code>&lt;html&gt;
      &lt;head&gt;
          &lt;meta http-equiv="Content-Type" content="text/html; charset=utf-8" /&gt;
          &lt;title&gt;B Koodak test&lt;/title&gt;
          &lt;link href='http://www.font-api.ir/css/B Koodak={font-api.ir}.css' rel='stylesheet'
          type='text/css'&gt;
          &lt;style&gt;
               .myclass{
               font-family:B Koodak,'B Koodak',tahoma;
               font-size:12px;
              }
          &lt;/style&gt;
      &lt;/head&gt;
  
      &lt;body&gt;
          &lt;div class="myclass"&gt;This Is Test Text.&lt;/div&gt;
      &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>for example if use access this link:</p>
  
  <p><a href="http://www.font-api.ir/css/B%20Koodak=%7Bfont-api.ir%7D.css" rel="nofollow noreferrer">http://www.font-api.ir/css/B Koodak={font-api.ir}.css</a></p>
  
  <p>this content is in base64 in above file: (thanks @Barmar and @Cracker0dks)</p>
  
  <p>Rk9OVC1BUEkuaXI6DQpTYWxhbSENCnNoYXlhZCBsYXplbSBiYXNoYWQgYmVkYW5pZCBrZSBjb3B5
  IGthcmRhbiBrYXJlIGtob29iaSBuaXN0IQ0KbG90ZmFuIGZvbnRlIG1vcmVkZSBuYXphcmUga2hv
  ZCByYSBheiBmb250LWFwaS5pciBlbnRla2hhYiBrb25pZC4NCg==</p>
  
  <p>This is decoded content. This is a message that say please no copy my css file (in persian language):</p>
  
  <pre><code>FONT-API.ir:
  Salam!
  shayad lazem bashad bedanid ke copy kardan kare khoobi nist!
  lotfan fonte morede nazare khod ra az font-api.ir entekhab konid.
  </code></pre>
  
  <p>This is my chrome developer tools image:
  <img src="https://i.stack.imgur.com/k60Pl.jpg" alt="chrome developer tools image"></p>
  
  <p>Network tab, Request header and response:
  <img src="https://i.stack.imgur.com/Ysec3.jpg" alt="chrome developer tools image network tab">
  <img src="https://i.stack.imgur.com/amFeS.png" alt="enter image description here">
  <img src="https://i.stack.imgur.com/6jMmd.png" alt="enter image description here"></p>