body {
  font-family: "Roboto", sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f3f4f6;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

:root {
  --primary: #31475e;
  --primary-dark: #26384b;
  --primary-light: #3d5670;
  --bg: #f3f4f6;
  --card-bg: #ffffff;
  --text-dark: #223548;
  --text-muted: #6f7f8f;
  --border: #cfd6dd;
  --input-bg: #ffffff;
  --shadow: 0 10px 24px rgba(0, 0, 0, 0.06);
}

.header {
  background-color: var(--primary);
  color: #ffffff;
  padding: 20px;
  text-align: center;
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.12);
}

.header h1 {
  margin: 0;
  font-weight: 700;
  font-size: 1.8rem;
}

.header p {
  margin: 5px 0 0;
  font-size: 1rem;
  color: #e8edf3;
}

.main-container {
  display: flex;
  justify-content: center;
  align-items: center;
  flex: 1;
  padding: 40px 20px;
}

.login-container {
  background-color: var(--card-bg);
  padding: 40px;
  border-radius: 16px;
  box-shadow: var(--shadow);
  width: 100%;
  max-width: 400px;
}

.login-container h1 {
  text-align: center;
  color: var(--text-dark);
  margin-bottom: 30px;
  font-size: 24px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 600;
  color: var(--text-dark);
}

.form-group input {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 16px;
  box-sizing: border-box;
  background-color: var(--input-bg);
  color: var(--text-dark);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-group input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(49, 71, 94, 0.12);
}

.form-group input::placeholder {
  color: #8b98a5;
}

.submit-btn {
  width: 100%;
  padding: 15px;
  background-color: var(--primary);
  color: #ffffff;
  border: none;
  border-radius: 8px;
  font-size: 16px;
  font-weight: 700;
  cursor: pointer;
  text-transform: uppercase;
  transition: background-color 0.3s ease, transform 0.2s ease;
}

.submit-btn:hover {
  background-color: var(--primary-dark);
  transform: translateY(-1px);
}

.forgot-password {
  text-align: center;
  margin-top: 15px;
}

.forgot-password a {
  text-decoration: none;
  color: var(--primary);
  font-weight: 600;
}

.forgot-password a:hover {
  text-decoration: underline;
}

.footer {
  background-color: var(--primary);
  color: #ffffff;
  padding: 15px 0;
  text-align: center;
  font-size: 14px;
}

.footer span {
  font-weight: 700;
  font-size: 16px;
  text-transform: uppercase;
}

.footer em {
  font-style: italic;
  color: #e8edf3;
}

.flash-messages {
  margin-bottom: 20px;
}

.alert {
  padding: 15px;
  border-radius: 6px;
  margin-bottom: 10px;
  font-size: 16px;
  font-weight: bold;
}

.alert.success {
  background-color: #d4edda;
  color: #155724;
  border: 1px solid #c3e6cb;
}

.alert.danger {
  background-color: #f8d7da;
  color: #721c24;
  border: 1px solid #f5c6cb;
}

@media (max-width: 768px) {
  .login-container {
    padding: 28px 22px;
  }

  .header h1 {
    font-size: 1.6rem;
  }

  .login-container h1 {
    font-size: 22px;
  }
}