body {
  font-family: Arial, sans-serif;
  margin: 0;
  background: #f4f6f8;
  color: #333;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 30px;
  background: white;
  border-bottom: 1px solid #ddd;
}

.logo {
  height: 40px;
}

nav a {
  margin-left: 15px;
  text-decoration: none;
  color: #333;
  font-weight: 500;
}

nav a:hover {
  color: #007bff;
}

main {
  padding: 40px;
  text-align: center;
}

.card {
  max-width: 400px;
  margin: 80px auto;
  background: white;
  padding: 30px;
  border-radius: 10px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.card h2 {
  margin-top: 0;
  margin-bottom: 20px;
}

input {
  display: block;
  width: 100%;
  margin-bottom: 15px;
  padding: 12px;
  box-sizing: border-box;
  border: 1px solid #ddd;
  border-radius: 5px;
  font-size: 14px;
  transition: border-color 0.2s, box-shadow 0.2s;
}

input:focus {
  outline: none;
  border-color: #007bff;
  box-shadow: 0 0 5px rgba(0, 123, 255, 0.2);
}

.btn {
  display: inline-block;
  padding: 10px 25px;
  background: #007bff;
  color: white !important;
  border-radius: 5px;
  border: none;
  cursor: pointer;
  font-size: 16px;
  text-decoration: none;
  transition: background 0.2s;
}

.btn:hover {
  background: #0056b3;
}

.card .btn {
  display: block;
  width: 100%;
}

a {
  text-decoration: none;
  color: #007bff;
}

.card a {
  display: inline-block;
  margin-top: 15px;
  color: #777;
  font-size: 14px;
}

.card a:hover {
  color: #333;
}

footer {
  text-align: center;
  padding: 40px 20px;
  color: #777;
  font-size: 0.9em;
}

.error-message {
  display: none;
  background: #fee2e2;
  color: #991b1b;
  border: 1px solid #fecaca;
  padding: 12px;
  border-radius: 5px;
  margin-bottom: 20px;
  font-size: 14px;
  animation: shake 0.4s ease-in-out;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-10px); }
  40% { transform: translateX(10px); }
  60% { transform: translateX(-10px); }
  80% { transform: translateX(10px); }
}