* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #1a1a2e;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  color: #fff;
}
.login-card {
  background: #fff;
  border-radius: 16px;
  padding: 2.5rem;
  width: 360px;
  text-align: center;
  box-shadow: 0 20px 40px rgba(0,0,0,0.3);
}
.login-card h1 {
  color: #1a1a2e;
  font-size: 1.4rem;
  margin-bottom: 0.5rem;
}
.login-card p {
  color: #888;
  font-size: 0.85rem;
  margin-bottom: 1.5rem;
}
.pin-inputs {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
  margin-bottom: 1.5rem;
}
.pin-inputs input {
  width: 52px;
  height: 60px;
  text-align: center;
  font-size: 1.5rem;
  font-weight: 700;
  border: 2px solid #ddd;
  border-radius: 12px;
  outline: none;
  transition: border-color 0.2s;
  color: #1a1a2e;
}
.pin-inputs input:focus {
  border-color: #4a6cf7;
  box-shadow: 0 0 0 3px rgba(74,108,247,0.15);
}
.pin-inputs input.error {
  border-color: #ef4444;
  animation: shake 0.4s;
}
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-6px); }
  75% { transform: translateX(6px); }
}
.btn-login {
  width: 100%;
  padding: 0.75rem;
  background: #4a6cf7;
  color: #fff;
  border: none;
  border-radius: 10px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s;
}
.btn-login:hover { background: #3b5de7; }
.btn-login:disabled {
  background: #ccc;
  cursor: not-allowed;
}
.error-msg {
  color: #ef4444;
  font-size: 0.85rem;
  margin-top: 1rem;
  min-height: 1.2rem;
}