css disable input

 <input type="text" name="username" value="admin" tabindex="-1" >

 <style type="text/css">
  input[name=username] {
    pointer-events: none;
   }
 </style>

<input type="text" name="username" value="admin" >
<style type="text/css">
  input[name=username] {
    disabled: true; /* Does not work */
  }
</style>

<input type="text" name="username" value="admin" >

<style type="text/css">
input[name=username] {
    pointer-events: none;
 }
</style>