External Css

what happened to it? this is my external css file code and i am using this css in my master page but it didnt show the required result

body {
ul
{margin:0;
 padding:0;
 list-style:none;   
    }
 ul li
 { float:left;
   width:150px;
   height:30px;
   line-height:30px;
   text-align:center;
   background:voilet;    
     }  
     ul li a
     {
         text-decoration:None;
         color:White;
        
         }
     ul li li
     { background:voilet;
       color:White;
        }   
  ul li li:hover
  { background:Gray;
    color:White; 
    display:none;   
      }     
       
ul li li a
{
    text-decoration:none;
    color:White;



{
 

 
 
• HomePage

 
• class schedule

 
• syllabus
    
  
   
  • subjects
  
   
  • books
  
   
  • course detail
  
   

 
• assignments

 
• fee record

 
• faculty info

 
• class teacher info

 
• examinations
    
  
   
  • schedule
  
   
  • results
  
   

   
• Holidays info

   

}
}