style.css

* {
  margin: 0px;
  padding: 0px;
}
body {
  font-size: 120%;
  background: #F8F8FF;
}

.header {
  width: 30%;
  margin: 50px auto 0px;
  color: rgb(174, 58, 58);
  background: #5cfaff;
  text-align: center;
  border: 1px solid #0d6ff0;
  border-bottom: none;
  border-radius: 10px 10px 0px 0px;
  padding: 20px;
}
form, .content {
  width: 30%;
  margin: 0px auto;
  padding: 20px;
  border: 1px solid #398efd;
  background: rgb(255, 81, 81);
  border-radius: 0px 0px 10px 10px;
}
.input-group {
  margin: 10px 0px 10px 0px;
}
.input-group label {
  display: block;
  text-align: left;
  margin: 3px;
}
.input-group input {
  height: 30px;
  width: 93%;
  padding: 5px 10px;
  font-size: 16px;
  border-radius: 5px;
  border: 1px solid rgb(77, 77, 77);
}
.btn {
  padding: 10px;
  font-size: 15px;
  color: rgb(204, 204, 204);
  background: #3ff9ff;
  border: none;
  border-radius: 5px;
}
.error {
  width: 92%; 
  margin: 0px auto; 
  padding: 10px; 
  border: 1px solid #ff4a47; 
  color: #ff3b38; 
  background: #c00000; 
  border-radius: 5px; 
  text-align: left;
}
.success {
  color: #25ff29; 
  background: #278800; 
  border: 1px solid #024e03;
  margin-bottom: 20px;
}