table, th, td {  
    border: 5px solid white;  
    border-collapse: collapse;  
}  
th, td {  
    padding: 10px;  
}  
table#alter tr {  
    background-color: lightgreen;  
}  
 
table#alter th {  
    width: 15;
    color: white;  
    background-color: green;
    
    
    
}