body {
  font-family: Arial, sans-serif;
  background: linear-gradient(to right, #4facfe, #00f2fe);
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
}

.container {
  background: #fff;
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 5px 20px rgba(0,0,0,0.2);
  width: 350px;
}

h1 {
  text-align: center;
  margin-bottom: 20px;
  color: #333;
}

.form-group {
  margin-bottom: 15px;
  position: relative;
}

label {
  display: block;
  margin-bottom: 5px;
  color: #333;
}

input {
  width: 100%;
  padding: 10px;
  border-radius: 6px;
  border: 1px solid #ccc;
  font-size: 16px;
}

input:focus {
  outline: none;
  border-color: #4facfe;
}

small {
  color: red;
  position: absolute;
  bottom: -18px;
  left: 0;
  visibility: hidden;
}

button {
  width: 100%;
  padding: 12px;
  font-size: 16px;
  border: none;
  border-radius: 8px;
  background: #4facfe;
  color: white;
  cursor: pointer;
  transition: 0.3s;
}

button:hover {
  background: #00c6fb;
}

.form-group.success input {
  border-color: green;
}

.form-group.error input {
  border-color: red;
}

.form-group.error small {
  visibility: visible;
}