body{
  position: absolute !important;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
.w600{
  width: 600px;
}
.w460{
  width: 460px;
}
.button{
  background-color: #74BC6C;
  width: 100%;
}
input[type="password"]{
  font-size: 120%;
}
@media screen and (max-width:640px){
  .w600, .w460{
    width: 100%;
    padding: 10px;
  }

}
/*footer*/
.footer{
  margin-top: 50px;
  padding: 0;
  background-color: #fff;
  text-align: center;
  padding-bottom: 1em;
}
@media screen and (max-width: 640px) {
  footer span.br{
    display: block;
  }
}
.copy{
  display: block;
  margin-top: 1em;
  padding-top: 1em;
  border-top: 1px solid black;
}