.nav_bar
{
    background-color:Blue; 
    color:white;
    font-size:25pt;
    font-weight:bold;
    font-family:微软雅黑;width:149px;height:70px;
    cursor:pointer
}


.A_title
{
    display:block;
    color:#2b2525;
    font-family:微软雅黑;
    font-size:25pt;
    font-weight:bold;
    font-style:italic;
    margin-left:120px
}

.B_title
{
    display:inline-block;
    background-color:black;
    color:white;
    font-family:微软雅黑;
    font-size:20pt;
    font-weight:bold;   
    margin-left:160px;
    border:2px solid silver ;
    cursor:pointer;
    width:300px     
      
}



.B2_title
{
    display:inline-block;
    background-color:black;
    color:white;
    font-family:微软雅黑;
    font-size:20pt;      
    border:2px solid silver ;
    cursor:pointer;
    width:550px     
      
}



tttttt 
{
	
    
}