body {
  font-family: sans-serif;
  padding: 20px;
  background: #f8f8f8;
}

h1, h2 {
  color: #333;
}

label {
  display: block;
  margin-top: 10px;
  font-weight: bold;
}

input {
  width: 100%;
  padding: 8px;
  margin-top: 4px;
  margin-bottom: 8px;
  border: 1px solid #ccc;
  border-radius: 4px;
}

input.invalid {
  border-color: red;
  box-shadow: 0 0 4px red;
  outline: none;
}

.error-message {
  color: red;
  font-size: 0.9em;
  margin: -4px 0 8px;
}

button {
  padding: 8px 16px;
  border: none;
  background: #007bff;
  color: white;
  border-radius: 4px;
  cursor: pointer;
}

button:hover {
  background: #0056b3;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 20px;
}

th, td {
  border: 1px solid #ddd;
  padding: 8px;
  text-align: center;
}

th {
  background-color: #f0f0f0;
}