table
{
  margin-left: auto;
  margin-right: auto;
}

html, body
{
  width: 100%;
}

#login
{
  width: 400px;
  position: relative;
  margin: 10% auto;
  padding: 5px 20px 5px 20px;
  border-radius: 10px;
  background: #aaa;
}