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

header {
  background: #111827;
  color: white;
  padding: 25px;
  text-align: center;
}

header input {
  margin-top: 15px;
  padding: 12px;
  width: 90%;
  max-width: 420px;
  border-radius: 8px;
  border: none;
  font-size: 16px;
}

#codes {
  max-width: 900px;
  margin: 30px auto;
  padding: 0 15px;
}

.card {
  background: white;
  border-radius: 12px;
  padding: 18px;
  margin-bottom: 15px;
  border: 1px solid #e5e7eb;
}

.card h3 {
  margin: 0 0 10px;
}

.code {
  display: inline-block;
  padding: 10px 14px;
  background: #e0ecff;
  color: #1e40af;
  font-weight: bold;
  border-radius: 8px;
  cursor: pointer;
}

.code:hover {
  background: #c7dbff;
}

footer {
  text-align: center;
  padding: 20px;
  color: #6b7280;
}