* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
  background-color: #f5f7fa;
  color: #333;
  line-height: 1.6;
}

header {
  background-color: #2c3e50;
  color: white;
  padding: 1rem 0;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  margin-bottom: 2rem;
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

header h1 {
  font-size: 1.5rem;
}

nav {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

nav a, nav button {
  color: white;
  text-decoration: none;
  border: none;
  background: none;
  cursor: pointer;
  font-size: 0.95rem;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  transition: background-color 0.3s;
}

nav a:hover, nav button:hover {
  background-color: rgba(255,255,255,0.1);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

.page {
  display: none;
}

.page.active {
  display: block;
}

.hero {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 4rem 1rem;
  text-align: center;
  border-radius: 8px;
  margin-bottom: 2rem;
}

.hero h2 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.1rem;
  margin-bottom: 2rem;
}

.btn-group {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 1rem;
  transition: all 0.3s;
}

.btn-primary {
  background-color: #667eea;
  color: white;
}

.btn-primary:hover {
  background-color: #5568d3;
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
  background-color: #e74c3c;
  color: white;
}

.btn-secondary:hover {
  background-color: #c0392b;
}

.btn-success {
  background-color: #27ae60;
  color: white;
}

.btn-success:hover {
  background-color: #229954;
}

.form-group {
  margin-bottom: 1.5rem;
  display: flex;
  flex-direction: column;
}

.form-group label {
  margin-bottom: 0.5rem;
  font-weight: 600;
  color: #2c3e50;
}

.form-group input,
.form-group select,
.form-group textarea {
  padding: 0.75rem;
  border: 2px solid #ecf0f1;
  border-radius: 4px;
  font-size: 1rem;
  transition: border-color 0.3s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: #667eea;
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.card {
  background: white;
  border-radius: 8px;
  padding: 2rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  margin-bottom: 2rem;
}

.card h3 {
  color: #2c3e50;
  margin-bottom: 1.5rem;
  border-bottom: 3px solid #667eea;
  padding-bottom: 0.5rem;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1rem;
}

table thead {
  background-color: #ecf0f1;
}

table th,
table td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid #ecf0f1;
}

table th {
  font-weight: 600;
  color: #2c3e50;
}

table tbody tr:hover {
  background-color: #f9f9f9;
}

.form-container {
  background: white;
  border-radius: 8px;
  padding: 2rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  margin-bottom: 2rem;
  max-width: 500px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-row.full {
  grid-template-columns: 1fr;
}

.alert {
  padding: 1rem;
  border-radius: 4px;
  margin-bottom: 1rem;
  display: none;
}

.alert.show {
  display: block;
}

.alert-success {
  background-color: #d4edda;
  color: #155724;
  border: 1px solid #c3e6cb;
}

.alert-error {
  background-color: #f8d7da;
  color: #721c24;
  border: 1px solid #f5c6cb;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 2rem;
  border-radius: 8px;
  text-align: center;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.stat-card h4 {
  font-size: 0.9rem;
  opacity: 0.9;
  margin-bottom: 0.5rem;
  text-transform: uppercase;
}

.stat-card .value {
  font-size: 2rem;
  font-weight: bold;
}

.auth-container {
  max-width: 400px;
  margin: 3rem auto;
}

.auth-form {
  background: white;
  border-radius: 8px;
  padding: 2rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.auth-form h2 {
  margin-bottom: 1.5rem;
  color: #2c3e50;
}

.auth-required-note {
  border-left: 4px solid #667eea;
}

.auth-required-note p {
  color: #5f6c7b;
}

.empty-state {
  text-align: center;
  padding: 3rem;
  color: #95a5a6;
}

.empty-state p {
  font-size: 1.1rem;
}

@media (max-width: 768px) {
  header h1 {
    font-size: 1.2rem;
  }

  nav {
    gap: 1rem;
  }

  nav a, nav button {
    padding: 0.35rem 0.75rem;
    font-size: 0.85rem;
  }

  .hero h2 {
    font-size: 1.8rem;
  }

  .btn-group {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  table {
    font-size: 0.9rem;
  }

  table th,
  table td {
    padding: 0.75rem;
  }

  .stats-grid {
    grid-template-columns: 1fr;
  }
}