html,
body {
  height: 100%;
  border-color: red;
}

body {
  display: flex;
  align-items: center;
  padding-top: 40px;
  padding-bottom: 40px;
  background-color: gold;
}

.form-signin {
  width: 100%;
  max-width: 330px;
  padding: 15px;
  margin: auto;
}

.form-signin .checkbox {
  font-weight: 400;
}

.form-signin .form-floating:focus-within {
  z-index: 2;
}

.top {
  margin-bottom: 3px;
  border-radius: 7;

}
.middle{
    margin-bottom: 3px;
    border-radius: 7;
  }


.bottom {
  margin-bottom: 10px;
  border-radius: 7;
}

.bd-placeholder-img {
    font-size: 1.125rem;
    text-anchor: middle;
    -webkit-user-select: none;
    -moz-user-select: none;
    user-select: none;
  }

  @media (min-width: 768px) {
    .bd-placeholder-img-lg {
      font-size: 3.5rem;
    }
  }