* {
  box-sizing: border-box;
  font-family: Arial, Helvetica, sans-serif;
}

body {
  margin: 0;
  background: #f4f6f8;
  color: #111;
}

.header {
  background: #1f2937;
  color: #fff;
  padding: 14px 20px;
  font-size: 18px;
}

.nav {
  background: #111827;
  display: flex;
  gap: 12px;
  padding: 10px 20px;
}

.nav a {
  color: #e5e7eb;
  text-decoration: none;
  padding: 8px 12px;
  border-radius: 4px;
}

.nav a:hover {
  background: #374151;
}

.container {
  padding: 20px;
}

.card {
  background: #fff;
  padding: 16px;
  border-radius: 6px;
  border: 1px solid #e5e7eb;
  margin-bottom: 12px;
}

button {
  background: #2563eb;
  color: #fff;
  border: none;
  padding: 8px 14px;
  border-radius: 4px;
  cursor: pointer;
}

button:hover {
  background: #1d4ed8;
}

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

th, td {
  border: 1px solid #e5e7eb;
  padding: 10px;
  text-align: left;
}

th {
  background: #f3f4f6;
}