:root {
  --color-primary: #1677ff;
  --color-primary-hover: #4096ff;
  --color-primary-active: #0958d9;
  --color-success: #52c41a;
  --color-warning: #faad14;
  --color-error: #ff4d4f;
  --color-text: #1f1f1f;
  --color-text-secondary: #666;
  --color-text-tertiary: #999;
  --color-border: #d9d9d9;
  --color-border-light: #f0f0f0;
  --color-bg: #f5f5f5;
  --color-bg-white: #fff;
  --color-bg-hover: #f0f7ff;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-xxl: 48px;
  --font-size-xs: 12px;
  --font-size-sm: 14px;
  --font-size-md: 16px;
  --font-size-lg: 20px;
  --font-size-xl: 24px;
  --font-size-xxl: 32px;
  --max-width: 1200px;
  --sidebar-width: 220px;
  --header-height: 56px;
  --transition: all 0.2s ease;
}

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

html, body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: var(--font-size-sm);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: var(--color-primary-hover);
}

button {
  cursor: pointer;
  font-family: inherit;
  border: none;
  outline: none;
  transition: var(--transition);
}

input, select, textarea {
  font-family: inherit;
  font-size: inherit;
  outline: none;
  transition: var(--transition);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: 8px 20px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  font-weight: 500;
  white-space: nowrap;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

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

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

.btn-primary:disabled {
  background: #d9d9d9;
  color: #999;
  cursor: not-allowed;
}

.btn-outline {
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text);
}

.btn-outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

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

.btn-danger:hover {
  opacity: 0.85;
}

.btn-sm {
  padding: 4px 12px;
  font-size: var(--font-size-xs);
}

.btn-lg {
  padding: 12px 32px;
  font-size: var(--font-size-md);
}

.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-size: var(--font-size-sm);
  color: var(--color-text);
  font-weight: 500;
}

.form-input {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg-white);
  color: var(--color-text);
  font-size: var(--font-size-sm);
}

.form-input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 2px rgba(22,119,255,0.1);
}

.form-input::placeholder {
  color: var(--color-text-tertiary);
}

.form-error {
  margin-top: var(--spacing-xs);
  font-size: var(--font-size-xs);
  color: var(--color-error);
}

.form-hint {
  margin-top: var(--spacing-xs);
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
}

.card {
  background: var(--color-bg-white);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  padding: var(--spacing-lg);
}

.alert {
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  margin-bottom: var(--spacing-md);
}

.alert-error {
  background: #fff2f0;
  border: 1px solid #ffccc7;
  color: var(--color-error);
}

.alert-success {
  background: #f6ffed;
  border: 1px solid #b7eb8f;
  color: var(--color-success);
}

.alert-warning {
  background: #fffbe6;
  border: 1px solid #ffe58f;
  color: var(--color-warning);
}

.alert-info {
  background: #e6f4ff;
  border: 1px solid #91caff;
  color: var(--color-primary);
}

.tag {
  display: inline-block;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-xs);
  font-weight: 500;
}

.tag-green {
  background: #f6ffed;
  color: var(--color-success);
  border: 1px solid #b7eb8f;
}

.tag-red {
  background: #fff2f0;
  color: var(--color-error);
  border: 1px solid #ffccc7;
}

.tag-blue {
  background: #e6f4ff;
  color: var(--color-primary);
  border: 1px solid #91caff;
}

.tag-gray {
  background: #f5f5f5;
  color: var(--color-text-tertiary);
  border: 1px solid var(--color-border);
}

.tag-orange {
  background: #fff7e6;
  color: #fa8c16;
  border: 1px solid #ffd591;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-size-sm);
}

th {
  text-align: left;
  padding: 12px 16px;
  background: #fafafa;
  border-bottom: 1px solid var(--color-border-light);
  font-weight: 500;
  color: var(--color-text-secondary);
  white-space: nowrap;
}

td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--color-border-light);
  color: var(--color-text);
}

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

.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-lg);
}

.pagination button {
  min-width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background: var(--color-bg-white);
  color: var(--color-text);
  font-size: var(--font-size-xs);
}

.pagination button:hover:not(:disabled) {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.pagination button:disabled {
  cursor: not-allowed;
  opacity: 0.5;
}

.pagination .page-info {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  padding: 0 var(--spacing-sm);
}

.loading {
  display: inline-block;
  width: 16px;
  height: 16px;
  border: 2px solid var(--color-border-light);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.empty-state {
  text-align: center;
  padding: var(--spacing-xxl) var(--spacing-lg);
  color: var(--color-text-tertiary);
}

.empty-state .icon {
  font-size: 48px;
  margin-bottom: var(--spacing-md);
}

.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0,0,0,0.45);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.modal {
  background: var(--color-bg-white);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: var(--spacing-xl);
  min-width: 400px;
  max-width: 90vw;
  max-height: 90vh;
  overflow-y: auto;
}

.modal-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  margin-bottom: var(--spacing-lg);
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-lg);
}

.toast-container {
  position: fixed;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2000;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.toast {
  padding: 10px 20px;
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  box-shadow: var(--shadow-md);
  animation: toast-in 0.3s ease;
}

@keyframes toast-in {
  from { opacity: 0; transform: translateY(-20px); }
  to { opacity: 1; transform: translateY(0); }
}

.toast-success {
  background: #f6ffed;
  border: 1px solid #b7eb8f;
  color: var(--color-success);
}

.toast-error {
  background: #fff2f0;
  border: 1px solid #ffccc7;
  color: var(--color-error);
}

.toast-info {
  background: #e6f4ff;
  border: 1px solid #91caff;
  color: var(--color-primary);
}

@media (max-width: 768px) {
  :root {
    --spacing-lg: 16px;
    --spacing-xl: 24px;
    --spacing-xxl: 32px;
    --sidebar-width: 0px;
  }

  .modal {
    min-width: auto;
    width: 90vw;
    padding: var(--spacing-lg);
  }

  table {
    font-size: var(--font-size-xs);
  }

  th, td {
    padding: 8px 10px;
  }
}