body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 1rem 2rem;
  background: #f5f5f5;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

h1 {
  margin: 0.5rem 0;
}

nav a {
  margin-right: 1rem;
  text-decoration: none;
  color: #0066cc;
}

nav a:hover {
  text-decoration: underline;
}

main {
  background: #ffffff;
  padding: 1rem 1.5rem;
  border-radius: 8px;
  box-shadow: 0 0 5px rgba(0,0,0,0.1);
}

form {
  display: flex;
  flex-direction: column;
  max-width: 400px;
}

form label {
  margin-bottom: 0.5rem;
}

form input,
form select,
form textarea {
  padding: 0.4rem;
  margin-top: 0.2rem;
}

button {
  margin-top: 0.8rem;
  padding: 0.5rem 1rem;
  cursor: pointer;
}

.error {
  background: #ffdddd;
  border: 1px solid #cc0000;
  padding: 0.5rem;
  margin-bottom: 1rem;
}

table {
  width: 100%;
  border-collapse: collapse;
  background: #ffffff;
}

table th,
table td {
  border: 1px solid #cccccc;
  padding: 0.4rem 0.5rem;
  text-align: left;
}

table th {
  background: #eeeeee;
}