body {
  background-color: #121212;
  color: #ddd;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  transition: background-color 0.3s, color 0.3s;
}

.login-box {
  background-color: #1e1e1e;
  padding: 40px 30px;
  border-radius: 12px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.8);
  width: 100%;
  max-width: 400px;
  transition: background-color 0.3s;
}

.login-box h1 {
  text-align: center;
  font-weight: 700;
  margin-bottom: 30px;
  color: #ccc;
  letter-spacing: 2px;
}

.form-control {
  background-color: #121212;
  border: 1.5px solid #333;
  color: #eee;
  transition: border-color 0.3s, background-color 0.3s;
  font-size: 1rem;
  border-radius: 6px;
  padding: 10px 14px;
}

.form-control::placeholder {
  color: #666;
  opacity: 1;
}

.form-control:focus {
  background-color: #262626;
  border-color: #a6a6a6;
  box-shadow: 0 0 6px #a6a6a6;
  color: #fff;
  outline: none;
}

.form-control.is-invalid {
  border-color: #e04f5f;
  background-color: #3b1b1e;
  color: #f5c6cb;
}

.btn-login {
  background: linear-gradient(45deg, #4a90e2, #357abd);
  border: none;
  color: #fff;
  font-weight: 700;
  padding: 12px 0;
  font-size: 1.1rem;
  border-radius: 8px;
  transition: background 0.3s, box-shadow 0.3s;
  width: 100%;
  cursor: pointer;
  user-select: none;
  box-shadow: 0 4px 10px rgba(70, 130, 180, 0.7);
}

.btn-login:hover,
.btn-login:focus {
  background: linear-gradient(45deg, #357abd, #285c8f);
  box-shadow: 0 6px 14px rgba(50, 100, 160, 0.9);
  outline: none;
}

.extra-options {
  text-align: center;
  margin-top: 15px;
  font-size: 0.9rem;
  color: #aaa;
}

.extra-options a {
  color: #7faaff;
  text-decoration: none;
  transition: color 0.3s;
}

.extra-options a:hover {
  text-decoration: underline;
  color: #a3c1ff;
}

.btn-login.loading {
  pointer-events: none; /* Evita clics */
  opacity: 0.7;
  position: relative;
}

.btn-login.loading::after {
  content: "";
  border: 2px solid #fff;
  border-top: 2px solid transparent;
  border-radius: 50%;
  width: 16px;
  height: 16px;
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  0% { transform: translateY(-50%) rotate(0deg); }
  100% { transform: translateY(-50%) rotate(360deg); }
}