:root {
  --primary: #4f46e5;
  --primary-light: #6366f1;
  --primary-dark: #4338ca;
  --success: #10b981;
  --danger: #ef4444;
  --warning: #f59e0b;
  --bg: #f8fafc;
  --card-bg: #ffffff;
  --text: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.05);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

/* ==================== 报名页面 ==================== */

.register-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem 1rem;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.register-card {
  background: var(--card-bg);
  border-radius: 16px;
  padding: 2.5rem;
  max-width: 500px;
  width: 100%;
  box-shadow: var(--shadow-lg);
}

.register-card h1 {
  font-size: 1.75rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 0.5rem;
  color: var(--text);
}

.register-card .subtitle {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 2rem;
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text);
}

.form-group label .required {
  color: var(--danger);
  margin-left: 2px;
}

.form-group input {
  width: 100%;
  padding: 0.625rem 0.875rem;
  border: 2px solid var(--border);
  border-radius: 8px;
  font-size: 0.95rem;
  transition: all 0.2s;
  outline: none;
  background: #fff;
}

.form-group input:focus {
  border-color: var(--primary-light);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.12);
}

.form-group input.error {
  border-color: var(--danger);
}

.error-msg {
  color: var(--danger);
  font-size: 0.8rem;
  margin-top: 0.25rem;
  display: none;
}

.error-msg.show {
  display: block;
}

.btn {
  display: inline-block;
  padding: 0.7rem 1.5rem;
  border: none;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  text-decoration: none;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  width: 100%;
}

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

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

.btn-primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

/* ==================== Toast 提示 ==================== */
.toast {
  position: fixed;
  top: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(-120%);
  background: #fff;
  padding: 1rem 1.5rem;
  border-radius: 8px;
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  z-index: 9999;
  transition: transform 0.3s ease;
  font-size: 0.9rem;
  font-weight: 500;
}

.toast.show {
  transform: translateX(-50%) translateY(0);
}

.toast.success {
  border-left: 4px solid var(--success);
}

.toast.error {
  border-left: 4px solid var(--danger);
}

.toast-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

/* ==================== 后台管理页面 ==================== */

.admin-page {
  min-height: 100vh;
  background: var(--bg);
}

.admin-header {
  background: #fff;
  border-bottom: 1px solid var(--border);
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.admin-header h1 {
  font-size: 1.25rem;
  font-weight: 700;
}

.admin-header .header-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.admin-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

/* 统计卡片 */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: #fff;
  border-radius: 12px;
  padding: 1.25rem;
  box-shadow: var(--shadow);
  text-align: center;
}

.stat-card .stat-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary);
}

.stat-card .stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

.stat-card.pending .stat-value { color: var(--warning); }
.stat-card.approved .stat-value { color: var(--success); }
.stat-card.rejected .stat-value { color: var(--danger); }

/* 工具栏 */
.toolbar {
  background: #fff;
  border-radius: 12px;
  padding: 1rem 1.25rem;
  box-shadow: var(--shadow);
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.toolbar-left {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 0.4rem 1rem;
  border: 2px solid var(--border);
  border-radius: 6px;
  background: #fff;
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

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

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

.search-input {
  padding: 0.4rem 0.75rem;
  border: 2px solid var(--border);
  border-radius: 6px;
  font-size: 0.85rem;
  outline: none;
  width: 200px;
  transition: all 0.2s;
}

.search-input:focus {
  border-color: var(--primary-light);
}

.toolbar-right {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-sm {
  padding: 0.4rem 1rem;
  font-size: 0.85rem;
  border-radius: 6px;
  border: none;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.2s;
}

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

.btn-export:hover {
  background: #059669;
}

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

.btn-batch:hover {
  background: #d97706;
}

.btn-batch:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* 表格 */
.table-container {
  background: #fff;
  border-radius: 12px;
  box-shadow: var(--shadow);
  overflow: hidden;
}

table {
  width: 100%;
  border-collapse: collapse;
}

th {
  background: #f1f5f9;
  padding: 0.75rem 1rem;
  text-align: left;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  white-space: nowrap;
}

td {
  padding: 0.75rem 1rem;
  border-top: 1px solid var(--border);
  font-size: 0.9rem;
}

tbody tr:hover {
  background: #f8fafc;
}

.status-badge {
  display: inline-block;
  padding: 0.2rem 0.75rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
}

.status-pending {
  background: #fef3c7;
  color: #92400e;
}

.status-approved {
  background: #d1fae5;
  color: #065f46;
}

.status-rejected {
  background: #fee2e2;
  color: #991b1b;
}

.action-btn {
  padding: 0.3rem 0.75rem;
  border: none;
  border-radius: 4px;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  margin-right: 0.25rem;
}

.action-approve {
  background: #d1fae5;
  color: #065f46;
}

.action-approve:hover {
  background: #10b981;
  color: #fff;
}

.action-reject {
  background: #fee2e2;
  color: #991b1b;
}

.action-reject:hover {
  background: #ef4444;
  color: #fff;
}

.action-delete {
  background: #f1f5f9;
  color: #475569;
}

.action-delete:hover {
  background: #64748b;
  color: #fff;
}

.empty-state {
  text-align: center;
  padding: 3rem 1rem;
  color: var(--text-muted);
}

.empty-state svg {
  margin: 0 auto 1rem;
  opacity: 0.4;
}

/* 复选框 */
.custom-checkbox {
  width: 16px;
  height: 16px;
  cursor: pointer;
  accent-color: var(--primary);
}

/* 响应式 */
@media (max-width: 768px) {
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .toolbar {
    flex-direction: column;
    align-items: stretch;
  }

  .toolbar-left,
  .toolbar-right {
    justify-content: center;
  }

  .search-input {
    width: 100%;
  }

  .admin-content {
    padding: 1rem;
  }

  th, td {
    padding: 0.5rem;
    font-size: 0.8rem;
  }

  .table-container {
    overflow-x: auto;
  }
}