.sign-box {
  width: 100%;
  min-width: 400px;
  max-width: 400px;
  min-height: 400px;
}

.sign-box .btn {
  margin: 16px auto 20px;
}

.sign-title {
  margin: 0 0 30px !important;
}

.page-center {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  margin: auto;
}