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

:root {
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --success-color: #10b981;
  --danger-color: #ef4444;
  --warning-color: #f59e0b;
  --bg-color: #f9fafb;
  --card-bg: #ffffff;
  --text-primary: #111827;
  --text-secondary: #6b7280;
  --border-color: #e5e7eb;
  --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
    sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background-color: var(--bg-color);
  background-image: url('/assets/images/background.jpg');
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  background-attachment: fixed;
  position: relative;
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(255, 255, 255, 0.7);
  z-index: -1;
  pointer-events: none;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
}

/* 居中容器样式 - 用于首页、登录、注册页面 */
.container.centered {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: calc(100vh - 40px);
  padding: 20px;
}

.container.centered .card {
  margin: 0;
  width: 100%;
}

.card {
  background: var(--card-bg);
  border-radius: 8px;
  padding: 24px;
  box-shadow: var(--shadow-md);
  margin-bottom: 24px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
  color: var(--text-primary);
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  font-size: 16px;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.btn {
  display: inline-block;
  padding: 12px 24px;
  font-size: 16px;
  font-weight: 500;
  text-align: center;
  text-decoration: none;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.2s;
  background-color: var(--primary-color);
  color: white;
}

.btn:hover {
  background-color: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn:active {
  transform: translateY(0);
}

.btn-success {
  background-color: var(--success-color);
}

.btn-success:hover {
  background-color: #059669;
}

.btn-danger {
  background-color: var(--danger-color);
}

.btn-danger:hover {
  background-color: #dc2626;
}

.btn-secondary {
  background-color: var(--text-secondary);
}

.btn-secondary:hover {
  background-color: #4b5563;
}

.btn-block {
  width: 100%;
  display: block;
}

.btn-sm {
  padding: 8px 16px;
  font-size: 14px;
}

.alert {
  padding: 12px 16px;
  border-radius: 6px;
  margin-bottom: 20px;
}

.alert-success {
  background-color: #d1fae5;
  color: #065f46;
  border: 1px solid #10b981;
}

.alert-error {
  background-color: #fee2e2;
  color: #991b1b;
  border: 1px solid #ef4444;
}

.alert-info {
  background-color: #dbeafe;
  color: #1e40af;
  border: 1px solid #2563eb;
}

.table-container {
  overflow-x: auto;
  margin-top: 20px;
}

table {
  width: 100%;
  border-collapse: collapse;
  background: var(--card-bg);
}

table th,
table td {
  padding: 12px;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

table th {
  background-color: var(--bg-color);
  font-weight: 600;
  color: var(--text-primary);
}

table tr:hover {
  background-color: var(--bg-color);
}

.modal {
  display: none;
  position: fixed;
  z-index: 1000;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  overflow: auto;
}

.modal.active {
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal-content {
  background-color: var(--card-bg);
  margin: auto;
  padding: 24px;
  border-radius: 8px;
  width: 90%;
  max-width: 500px;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.modal-header h2 {
  margin: 0;
}

.close {
  color: var(--text-secondary);
  font-size: 28px;
  font-weight: bold;
  cursor: pointer;
  border: none;
  background: none;
}

.close:hover {
  color: var(--text-primary);
}

.header {
  background: var(--card-bg);
  box-shadow: var(--shadow);
  padding: 16px 0;
  margin-bottom: 24px;
}

.header-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header h1 {
  font-size: 24px;
  color: var(--primary-color);
}

.nav-links {
  display: flex;
  gap: 16px;
}

.nav-links a {
  color: var(--text-primary);
  text-decoration: none;
  padding: 8px 16px;
  border-radius: 6px;
  transition: background-color 0.2s;
}

.nav-links a:hover {
  background-color: var(--bg-color);
}

.search-bar {
  display: flex;
  gap: 12px;
  margin-bottom: 20px;
}

.search-bar input {
  flex: 1;
  padding: 12px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  font-size: 16px;
}

.action-buttons {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.empty-state {
  text-align: center;
  padding: 48px 20px;
  color: var(--text-secondary);
}

.empty-state h3 {
  margin-bottom: 8px;
  color: var(--text-primary);
}

@media (max-width: 768px) {
  .container {
    padding: 12px;
  }
  
  .container.centered {
    min-height: calc(100vh - 24px);
    padding: 12px;
  }

  .card {
    padding: 16px;
  }

  .header-content {
    flex-direction: column;
    gap: 16px;
    align-items: flex-start;
  }

  .nav-links {
    width: 100%;
    flex-direction: column;
  }

  .search-bar {
    flex-direction: column;
  }

  .action-buttons {
    flex-direction: column;
  }

  .action-buttons .btn {
    width: 100%;
  }

  table {
    font-size: 14px;
  }

  table th,
  table td {
    padding: 8px;
  }
}