* {
  box-sizing: border-box;
}

body {
  font-family: Segoe UI, Arial, sans-serif;
  background: #f4f6f8;
  margin: 0;
  padding: 2rem 1rem;
  color: #1f2937;
}

.container {
  max-width: 680px;
  margin: 0 auto;
}

h1 {
  text-align: center;
  margin-bottom: 1.5rem;
}

.card {
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.1);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.card h2 {
  margin-top: 0;
  font-size: 1.1rem;
}

label {
  display: block;
  font-size: 0.85rem;
  margin-top: 0.75rem;
  margin-bottom: 0.25rem;
}

input, textarea {
  width: 100%;
  padding: 0.5rem;
  border: 1px solid #d1d5db;
  border-radius: 4px;
  font-size: 0.95rem;
}

textarea {
  height: 100px;
  resize: vertical;
  font-family: monospace;
  font-size: 0.8rem;
}

button {
  margin-top: 1rem;
  padding: 0.55rem 1.1rem;
  background: #2563eb;
  color: #fff;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.95rem;
}

button:hover {
  background: #1d4ed8;
}

.hint {
  font-size: 0.8rem;
  color: #6b7280;
}

.message {
  margin-top: 0.75rem;
  font-size: 0.9rem;
}

.message.error {
  color: #dc2626;
}

.message.success {
  color: #16a34a;
}

.hidden {
  display: none;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

th, td {
  padding: 0.5rem 0.6rem;
  text-align: right;
  border-bottom: 1px solid #eee;
  white-space: nowrap;
}

th:nth-child(1), td:nth-child(1),
th:nth-child(2), td:nth-child(2) {
  text-align: left;
}

thead th {
  color: #6b7280;
  font-weight: 600;
  font-size: 0.8rem;
  border-bottom: 2px solid #e5e7eb;
}

tr.fee-paid {
  color: #9ca3af;
}

.badge {
  display: inline-block;
  padding: 0.1rem 0.5rem;
  border-radius: 999px;
  font-size: 0.75rem;
}

.badge.paid {
  background: #dcfce7;
  color: #16a34a;
}

.badge.due {
  background: #fef3c7;
  color: #b45309;
}

pre {
  background: #f3f4f6;
  padding: 0.75rem;
  border-radius: 4px;
  overflow-x: auto;
  font-size: 0.85rem;
}