input[type=text] {
    width: 15%;
    padding: 10px 20px;
    margin: 5px 0;
    border: 1px solid black; 
}
input[type=password] {
    width: 15%;
    padding: 10px 20px;
    margin: 5px 0;
    border: 1px solid black; 
}

input[type=submit] {
    width: 10%;
    margin-left:100px;
    padding: 12px 20px;
    border: 1px solid #555;
    background-color: green;
    color:white;
    
}
.form{ 
    margin-left: 500px; 
    width: 100%;
}

.invalid { 
    color:red; 
    font-family: arial; 
    margin-left: 500px; 
}