input::placeholder,
textarea::placeholder {
    color: #777;
}
#div-form {
    background-color: lightslategrey;
    width: 600px;
    height: 650px;
}
#BT{
    width: 150px;
    height: 50px;
    display: block;
    background-color: midnightblue;
    color: #ffeeee;
    text-align: center;
    margin-left: 100px;
    cursor: pointer;
}