body {
  min-height: 100vh;
  margin: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(120deg, #0f1228 50%, #2ef200 50%);
  font-family: 'Sarabun', 'Prompt', 'Kanit', 'Segoe UI', sans-serif;
}
.main {
  background: #23284A;
  padding: 32px 28px;
  border-radius: 18px;
  box-shadow: 0 8px 32px 0 rgba(0,0,0,0.14);
  width: 100%;
  max-width: 370px;
  display: flex;
  flex-direction: column;
  align-items: center;
}
h2 {
  color: #fff;
  font-weight: 700;
  margin-bottom: 18px;
  text-align: center;
  letter-spacing: 0.3px;
}
form {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.form-group {
  display: flex;
  flex-direction: column;
  width: 100%;
}
label {
  color: #e0e0e0;
  font-size: 15px;
  margin-bottom: 3px;
  font-weight: 500;
}
input[type="text"],
input[type="password"] {
  background: #111427;
  color: #fff;
  border: 1px solid #333c5a;
  border-radius: 7px;
  padding: 10px 12px;
  font-size: 15px;
  outline: none;
  transition: border-color 0.2s;
  width: 100%;
  box-sizing: border-box;
}
input[type="text"]:focus,
input[type="password"]:focus {
  border-color: #6c63ff;
}
button {
  background: linear-gradient(90deg, #6c63ff 0%, #c62828 100%);
  color: #fff;
  font-size: 16px;
  border: none;
  border-radius: 7px;
  padding: 12px 0;
  font-weight: bold;
  letter-spacing: 1px;
  cursor: pointer;
  margin-top: 8px;
  box-shadow: 0 2px 8px rgba(108,99,255,0.08);
  transition: background 0.18s, box-shadow 0.18s;
}
button:hover {
  background: linear-gradient(90deg, #c62828 0%, #6c63ff 100%);
  box-shadow: 0 4px 16px rgba(108,99,255,0.18);
}
.error-message {
  color: #ffcccb;
  margin-bottom: 10px;
  font-size: 13px;
  text-align: center;
}