body {
  margin: 0;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
}

.overlay {
  height: 100%;
  width: 0;
  position: fixed;
  top: 0;
  left: 0;
  background-color: rgb(0,0,0);
  background-color: rgba(0, 0, 0, 0.5);
  overflow-x: hidden;
  transition: 0.5s;
  z-index: 10;
}

.overlay-content {
  position: relative;
  top: 75%;
  width: 100%;
  text-align: center;
  margin-top: 30px;
}

.overlay a {
  padding: 8px;
  text-decoration: solid;
  font-size: 20px;
  color: rgb(243, 255, 246);
  transition: 0.3s;
}

.overlay a:hover, .overlay a:focus {
  color: #337ab7;
}

.error {
  color: red;
  box-shadow: red;
}

.valid {
  color: green;
  box-shadow: green;
}

.btn-modal-warning {
  color: #fff;
  background-color: #f0ad4e;
  border-color: #eea236;
  width: 50%;
  margin-top: 0;
!important;
}

@media screen and (max-height: 450px) {
  .overlay a {font-size: 20px}
  .overlay .closebtn {
    font-size: 40px;
    top: 15px;
    right: 35px;
  }
}