/* ═══════════════════════════════════════════════════════
   智能组卷系统 — 基础样式
   桌面端 + 通用组件样式
   响应式规则 → responsive.css

   设计说明：因内网穿透隧道对静态资源有约 43KB 传输限制，
   CSS 拆分为两个文件 + 后端 gzip 压缩确保完整传输。
   ═══════════════════════════════════════════════════════ */

/* ── Design Tokens ──────────────────────────────────── */
:root {
  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --primary-light: #eef2ff;
  --primary-border: #dbeafe;
  --deep: #1e293b;
  --bg: #f8f7f4;
  --card: #ffffff;
  --border: #f0efec;
  --border-strong: #e8e6e1;
  --text: #1a1a2e;
  --text-secondary: #6b7280;
  --text-muted: #9ca3af;
  --accent-amber: #d97706;
  --accent-amber-bg: #fffbeb;
  --success: #10b981;
  --success-bg: #ecfdf5;
  --danger: #ef4444;
  --danger-bg: #fef2f2;
  --info: #3b82f6;
  --info-bg: #eef2ff;

  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 10px;
  --radius-xl: 12px;
  --radius-full: 9999px;

  --shadow-card: 0 1px 3px rgba(0,0,0,0.04);
  --shadow-hover: 0 4px 16px rgba(59,130,246,0.08);
  --shadow-elevated: 0 8px 24px rgba(0,0,0,0.08);
  --shadow-modal: 0 20px 60px rgba(0,0,0,0.15);

  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --ease-out: cubic-bezier(0, 0, 0.2, 1);
  --ease-in: cubic-bezier(0.4, 0, 1, 1);
  --ease-smooth: cubic-bezier(0.4, 0, 0.2, 1);

  --duration-fast: 150ms;
  --duration-normal: 250ms;
  --duration-slow: 350ms;
}

/* ── Reset & Base ───────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 15px; }
body {
  font-family: -apple-system, "Microsoft YaHei", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

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

/* ── Animations ─────────────────────────────────────── */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes slideInRight {
  from { opacity: 0; transform: translateX(30px); }
  to   { opacity: 1; transform: translateX(0); }
}
@keyframes slideOutLeft {
  to   { opacity: 0; transform: translateX(-20px) scale(0.96); }
}
@keyframes shimmer {
  0%   { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}
@keyframes spin {
  to { transform: rotate(360deg); }
}
@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(16,185,129,0.4); }
  50% { box-shadow: 0 0 0 8px rgba(16,185,129,0); }
}
@keyframes scaleIn {
  from { transform: scale(0.9) translateY(20px); opacity: 0; }
  to   { transform: scale(1) translateY(0); opacity: 1; }
}
@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

/* Respect user motion preferences */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* ── Page fade-in (applied via JS on main-content) ──── */
.main-content { animation: fadeUp var(--duration-slow) var(--ease-out) both; }

/* ── Layout ─────────────────────────────────────────── */
.layout { display: flex; min-height: 100vh; }

/* ── Sidebar ────────────────────────────────────────── */
.sidebar {
  width: 220px;
  background: var(--deep);
  color: #fff;
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 0; left: 0; bottom: 0;
  z-index: 100;
  overflow-y: auto;
}

.sidebar-header {
  padding: 20px 16px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}
.sidebar-header h1 { font-size: 1.15rem; font-weight: 600; }
.sidebar-header h1 a { color: #fff; transition: opacity var(--duration-fast); }
.sidebar-header h1 a:hover { opacity: 0.8; color: #fff; }

.sidebar-nav { flex: 1; padding: 8px 0; }

.nav-section { margin: 6px 0; }
.nav-section-title {
  padding: 6px 16px 4px;
  font-size: 0.7rem;
  font-weight: 600;
  color: rgba(255,255,255,0.35);
  text-transform: uppercase;
  letter-spacing: 1.2px;
}

.nav-item {
  display: block;
  padding: 10px 16px;
  color: rgba(255,255,255,0.65);
  font-size: 0.88rem;
  transition: all var(--duration-fast);
  border-left: 3px solid transparent;
  position: relative;
}
.nav-item:hover {
  color: #fff;
  background: rgba(255,255,255,0.06);
}
.nav-item.active {
  color: #fff;
  background: rgba(59,130,246,0.2);
  border-left-color: var(--primary);
}
.nav-icon {
  display: inline-block;
  width: 1.4em;
  text-align: center;
}
.nav-sub {
  padding-left: 36px;
  font-size: 0.83rem;
}

.sidebar-footer {
  padding: 14px 16px;
  font-size: 0.72rem;
  color: rgba(255,255,255,0.3);
  border-top: 1px solid rgba(255,255,255,0.08);
}
.sidebar-footer .user-info { display: flex; align-items: center; gap: 6px; margin-bottom: 4px; }
.sidebar-footer .user-name { color: rgba(255,255,255,0.8); font-size: 0.82rem; }
.sidebar-footer .user-badge {
  background: var(--primary);
  color: #fff;
  font-size: 0.62rem;
  padding: 1px 8px;
  border-radius: var(--radius-full);
}
.sidebar-footer .user-links { margin-bottom: 6px; }
.sidebar-footer .user-links a {
  color: rgba(255,255,255,0.4);
  margin-right: 12px;
  font-size: 0.72rem;
}
.sidebar-footer .user-links a:hover { color: var(--primary); }
.sidebar-footer .version { display: block; margin-top: 2px; }

/* ── Logout nav item ────────────────────────────────── */
.nav-logout { border-left-color: transparent !important; }
.nav-logout:hover { background: rgba(239,68,68,0.15) !important; color: #f87171 !important; }

/* ── Main Content ───────────────────────────────────── */
.main-content {
  margin-left: 220px;
  flex: 1;
  padding: 28px 32px;
  min-height: 100vh;
}

.page-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
  flex-wrap: wrap;
  gap: 12px;
}
.page-header h2 { font-size: 1.5rem; font-weight: 700; color: var(--deep); }
.header-actions { display: flex; gap: 8px; }

/* ── Flash Messages / Toast ─────────────────────────── */
.flash-messages {
  position: fixed;
  top: 20px; right: 20px;
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: 8px;
  pointer-events: none;
}
.flash-message {
  padding: 14px 20px;
  border-radius: var(--radius-xl);
  display: flex;
  align-items: center;
  gap: 10px;
  box-shadow: var(--shadow-elevated);
  animation: slideInRight 0.4s var(--ease-spring);
  pointer-events: auto;
  min-width: 280px;
  max-width: 420px;
  font-size: 0.9rem;
}
.flash-success { background: var(--success-bg); border-left: 3px solid var(--success); color: #065f46; }
.flash-danger  { background: var(--danger-bg); border-left: 3px solid var(--danger); color: #991b1b; }
.flash-info    { background: var(--info-bg); border-left: 3px solid var(--info); color: #1e40af; }
.flash-close {
  background: none; border: none; font-size: 1.1rem; cursor: pointer;
  color: inherit; opacity: 0.4; margin-left: auto; flex-shrink: 0;
}
.flash-close:hover { opacity: 0.8; }

/* ── Buttons ────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 8px 16px;
  border: 1.5px solid var(--border-strong);
  border-radius: var(--radius-md);
  background: var(--card);
  color: var(--text);
  font-size: 0.88rem;
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-smooth);
  text-decoration: none;
  white-space: nowrap;
  line-height: 1.4;
}
.btn:hover {
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(59,130,246,0.1);
}
.btn:active { transform: scale(0.97); }

.btn-primary {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}
.btn-primary:hover { background: var(--primary-hover); border-color: var(--primary-hover); color: #fff; box-shadow: 0 4px 12px rgba(59,130,246,0.25); }

.btn-success {
  background: var(--success);
  border-color: var(--success);
  color: #fff;
}
.btn-success:hover { background: #059669; border-color: #059669; color: #fff; box-shadow: 0 4px 12px rgba(16,185,129,0.25); }

.btn-danger {
  background: var(--danger);
  border-color: var(--danger);
  color: #fff;
}
.btn-danger:hover { background: #dc2626; border-color: #dc2626; color: #fff; box-shadow: 0 4px 12px rgba(239,68,68,0.25); }

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

.btn-sm { padding: 5px 12px; font-size: 0.8rem; border-radius: var(--radius-sm); }

/* ── Stats Grid (Dashboard) ─────────────────────────── */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-bottom: 28px;
}
.stat-card {
  background: var(--card);
  border-radius: var(--radius-xl);
  padding: 24px;
  display: flex;
  align-items: center;
  gap: 16px;
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
  transition: all var(--duration-normal) var(--ease-smooth);
  cursor: default;
}
.stat-card:hover {
  box-shadow: var(--shadow-hover);
  border-color: var(--primary-border);
  transform: translateY(-2px);
}
.stat-card .stat-icon {
  width: 48px; height: 48px;
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  flex-shrink: 0;
}
.stat-card .stat-icon.blue  { background: var(--primary-light); }
.stat-card .stat-icon.green { background: var(--success-bg); }
.stat-card .stat-icon.amber { background: var(--accent-amber-bg); }

.stat-number {
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--deep);
  line-height: 1.2;
}
.stat-label { font-size: 0.82rem; color: var(--text-secondary); }

/* ── Subject Grid (Dashboard) ───────────────────────── */
.subject-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
  margin-bottom: 28px;
}
.subject-card {
  background: var(--card);
  border-radius: var(--radius-xl);
  padding: 22px 16px;
  text-align: center;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-card);
  transition: all var(--duration-normal) var(--ease-spring);
  text-decoration: none;
  color: var(--text);
  display: block;
}
.subject-card:hover {
  transform: translateY(-4px) scale(1.02);
  box-shadow: var(--shadow-hover);
  border-color: var(--primary-border);
  color: var(--text);
}
.subject-card .subject-icon { font-size: 2.2rem; margin-bottom: 6px; }
.subject-card .subject-name { font-size: 0.95rem; font-weight: 600; margin-bottom: 4px; }
.subject-card .subject-stats { font-size: 0.75rem; color: var(--text-muted); display: flex; justify-content: center; gap: 10px; }

/* ── Section ────────────────────────────────────────── */
.section { margin-bottom: 32px; }
.section h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 14px;
  color: var(--deep);
  display: flex;
  align-items: center;
  gap: 6px;
}

/* ── Table ──────────────────────────────────────────── */
.table {
  width: 100%;
  background: var(--card);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
  border-collapse: collapse;
}
.table th, .table td {
  padding: 12px 20px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}
.table th {
  background: #faf9f7;
  font-weight: 600;
  font-size: 0.8rem;
  color: var(--text-secondary);
}
.table tr:last-child td { border-bottom: none; }
.table tr:hover td { background: #faf9f7; }

.actions { display: flex; gap: 6px; flex-wrap: nowrap; }

/* ── Sort Bar ───────────────────────────────────────── */
.sort-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--card);
  padding: 12px 20px;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
  margin-bottom: 14px;
  flex-wrap: wrap;
  gap: 10px;
}
.sort-left { display: flex; align-items: center; gap: 4px; }
.sort-item {
  padding: 6px 14px;
  font-size: 0.82rem;
  color: var(--text-secondary);
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: all var(--duration-fast);
  user-select: none;
  border: 1px solid transparent;
}
.sort-item:hover { color: var(--primary); background: var(--primary-light); }
.sort-item.active {
  color: var(--primary);
  background: var(--primary-light);
  border-color: var(--primary-border);
  font-weight: 500;
}
.sort-total { font-size: 0.82rem; color: var(--text-secondary); white-space: nowrap; }
.sort-total strong { color: var(--deep); }

/* ── Modern Filter Bar ──────────────────────────────── */
.filter-bar-modern {
  display: flex;
  gap: 12px;
  align-items: flex-end;
  flex-wrap: wrap;
  background: var(--card);
  padding: 16px 20px;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
  margin-bottom: 14px;
}
.filter-group { display: flex; flex-direction: column; gap: 3px; }
.filter-group label {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.filter-group select,
.filter-group input[type="text"] {
  padding: 8px 12px;
  border: 1.5px solid var(--border-strong);
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  min-width: 120px;
  background: var(--card);
  transition: all var(--duration-fast);
}
.filter-group select:focus,
.filter-group input[type="text"]:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(59,130,246,0.1);
}
.filter-group select { min-width: 120px; cursor: pointer; }
.filter-btn {
  padding: 8px 20px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--duration-fast);
  white-space: nowrap;
}
.filter-btn:hover { background: var(--primary-hover); transform: translateY(-1px); box-shadow: 0 2px 8px rgba(59,130,246,0.2); }
.filter-btn:active { transform: scale(0.97); }

/* ── Skeleton Loading ───────────────────────────────── */
.skeleton {
  background: var(--border-strong);
  border-radius: var(--radius-sm);
  position: relative;
  overflow: hidden;
}
.skeleton::after {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.4), transparent);
  animation: shimmer 1.5s infinite;
}

/* ── Results Container ──────────────────────────────── */
.results-loading {
  text-align: center;
  padding: 40px;
  color: var(--text-muted);
}
.results-loading::after {
  content: '';
  display: inline-block;
  width: 22px; height: 22px;
  border: 2.5px solid var(--border-strong);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  margin-left: 10px;
  vertical-align: middle;
}
.results-empty { text-align: center; padding: 60px 20px; color: var(--text-muted); }
.results-empty p { font-size: 1rem; }
.results-error { text-align: center; padding: 40px 20px; color: var(--danger); }

/* ── Pagination ─────────────────────────────────────── */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 12px;
  padding: 20px 0;
  color: var(--text-secondary);
  font-size: 0.88rem;
}

/* ── Empty State ────────────────────────────────────── */
.empty-state { text-align: center; padding: 60px 20px; color: var(--text-muted); }
.empty-state p { margin-bottom: 16px; font-size: 1rem; }

/* ── Quick Actions ──────────────────────────────────── */
.quick-actions { display: flex; gap: 12px; margin-top: 24px; }

/* ── Form ───────────────────────────────────────────── */
.form {
  background: var(--card);
  padding: 28px;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
  max-width: 960px;
  width: 100%;
  margin: 0 auto;
}
.form-row { display: flex; gap: 16px; margin-bottom: 16px; flex-wrap: wrap; }
.form-row .form-group { flex: 1; min-width: 160px; }
.form-group { margin-bottom: 16px; }
.form-group label {
  display: block;
  margin-bottom: 6px;
  font-weight: 500;
  font-size: 0.88rem;
  color: var(--text);
}
.form-group .required { color: var(--danger); }
.form-help { font-size: 0.8rem; color: var(--text-muted); margin-bottom: 6px; }

.form-group input[type="text"],
.form-group input[type="number"],
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 9px 12px;
  border: 1.5px solid var(--border-strong);
  border-radius: var(--radius-md);
  font-size: 0.92rem;
  font-family: inherit;
  transition: all var(--duration-fast);
  background: var(--card);
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(59,130,246,0.1);
}
.form-group textarea { resize: vertical; min-height: 80px; }
.form-actions {
  display: flex;
  gap: 12px;
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

/* ── Shake Animation ────────────────────────────────── */
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  10%, 50%, 90% { transform: translateX(-5px); }
  30%, 70% { transform: translateX(5px); }
}
.shake {
  animation: shake 0.5s var(--ease-smooth);
  border-color: var(--danger) !important;
  box-shadow: 0 0 0 3px rgba(239,68,68,0.15) !important;
}

/* ── Difficulty Number Buttons ──────────────────────── */
.difficulty-buttons { display: flex; gap: 8px; padding: 4px 0; flex-wrap: wrap; }
.diff-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px; height: 44px;
  border: 2px solid var(--border-strong);
  border-radius: var(--radius-md);
  background: var(--card);
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-smooth);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-secondary);
  user-select: none;
  position: relative;
}
.diff-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--primary-light);
  transform: translateY(-2px);
  box-shadow: 0 2px 8px rgba(59,130,246,0.12);
}
.diff-btn:active { transform: scale(0.93); }
.diff-btn.active {
  border-color: var(--primary);
  background: var(--primary);
  color: #fff;
  box-shadow: 0 3px 10px rgba(59,130,246,0.25);
  transform: translateY(-2px);
}
.diff-btn.active:hover {
  background: var(--primary-hover);
  border-color: var(--primary-hover);
  color: #fff;
}
.diff-btn-label {
  position: absolute;
  bottom: -18px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.6rem;
  font-weight: 400;
  color: var(--text-muted);
  white-space: nowrap;
  opacity: 0;
  transition: opacity var(--duration-fast);
}
.diff-btn.active .diff-btn-label,
.diff-btn:hover .diff-btn-label { opacity: 1; }

/* ── Difficulty Stars (keep for display) ────────────── */
.difficulty-stars { display: flex; gap: 6px; padding: 4px 0; }
.star-option {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px; height: 34px;
  border: 1.5px solid var(--border-strong);
  border-radius: var(--radius-md);
  background: var(--card);
  cursor: pointer;
  transition: all var(--duration-fast);
  font-size: 0.85rem;
  color: var(--border-strong);
  user-select: none;
}
.star-option:hover { border-color: var(--accent-amber); color: var(--accent-amber); background: var(--accent-amber-bg); }
.star-option.active { border-color: var(--accent-amber); background: var(--accent-amber-bg); color: var(--accent-amber); font-weight: 600; }
.star-option.active ~ .star-option { border-color: var(--border-strong); color: var(--border-strong); background: var(--card); }
.star-option.all-star { border-color: var(--border-strong); color: var(--text-muted); font-size: 0.8rem; }
.star-option.all-star.active { border-color: var(--primary); color: var(--primary); background: var(--primary-light); }
.difficulty-label { font-size: 0.78rem; color: var(--text-secondary); margin-right: 8px; font-weight: 500; }

/* ── Question Cards ─────────────────────────────────── */
.question-list { display: flex; flex-direction: column; gap: 10px; }
.question-card {
  background: var(--card);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
  overflow: hidden;
  transition: all var(--duration-normal) var(--ease-smooth);
}
.question-card:hover {
  box-shadow: var(--shadow-hover);
  border-color: var(--primary-border);
}

.qc-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: 16px 20px 0;
  gap: 12px;
}
.qc-left { display: flex; align-items: baseline; gap: 8px; flex-wrap: wrap; min-width: 0; }
.qc-number { font-weight: 700; font-size: 0.92rem; color: var(--deep); white-space: nowrap; }
.qc-tags { display: flex; gap: 6px; flex-wrap: wrap; }
.qc-tag {
  font-size: 0.72rem;
  padding: 2px 10px;
  border-radius: var(--radius-full);
  white-space: nowrap;
  font-weight: 500;
}
.qc-tag-type { color: var(--primary); background: var(--primary-light); }
.qc-tag-difficulty { color: var(--accent-amber); background: var(--accent-amber-bg); }

.qc-body {
  padding: 10px 20px;
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--text);
}
.qc-body img { max-width: 100%; max-height: 300px; display: block; margin: 8px 0; border-radius: var(--radius-sm); }
.qc-body table { border-collapse: collapse; max-width: 100%; margin: 8px 0; font-size: 0.85rem; }
.qc-body table td, .qc-body table th { border: 1px solid var(--border); padding: 6px 10px; }

.qc-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 20px;
  background: #faf9f7;
  border-top: 1px solid var(--border);
  flex-wrap: wrap;
  gap: 8px;
}
.qc-actions { display: flex; gap: 6px; flex-wrap: wrap; }

.qc-action-btn {
  padding: 4px 12px;
  font-size: 0.78rem;
  border: 1.5px solid var(--border-strong);
  border-radius: var(--radius-md);
  background: var(--card);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--duration-fast);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 3px;
}
.qc-action-btn:hover { border-color: var(--primary); color: var(--primary); }

.qc-action-btn.qc-add {
  border-color: var(--primary-border);
  color: var(--primary);
  background: var(--primary-light);
  font-weight: 500;
}
.qc-action-btn.qc-add:hover {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.qc-source { font-size: 0.76rem; color: var(--text-muted); }

/* ── Upload Area ────────────────────────────────────── */
.upload-area { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; }
.upload-area input[type="file"] { font-size: 0.88rem; }
.uploaded-images { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 8px; }
.image-chip {
  border: 1.5px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 4px;
  background: #faf9f7;
  cursor: pointer;
  transition: all var(--duration-fast);
}
.image-chip:hover { border-color: var(--primary); box-shadow: 0 0 0 2px rgba(59,130,246,0.15); }

/* ── Options (Question Form) ────────────────────────── */
.option-row {
  background: #faf9f7;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 14px;
  margin-bottom: 8px;
}
.option-header { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; }
.option-label { font-weight: 600; color: var(--deep); }
.option-row textarea { width: 100%; }

/* ── Paper Info ─────────────────────────────────────── */
.paper-info {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  background: var(--card);
  padding: 16px 20px;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
  margin-bottom: 24px;
}
.info-item { font-size: 0.92rem; color: var(--text); }
.info-item strong { color: var(--deep); }

/* ── Paper Preview ──────────────────────────────────── */
.paper-preview {
  background: var(--card);
  padding: 32px 40px;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
}
.paper-title-block { text-align: center; margin-bottom: 20px; }
.paper-title { font-size: 1.5rem; font-weight: 700; margin-bottom: 8px; color: var(--deep); }
.paper-meta {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
  display: flex;
  justify-content: center;
  gap: 24px;
}
.paper-blank { font-size: 0.88rem; color: var(--text-muted); }
.paper-section { margin-bottom: 24px; }
.paper-section h3 {
  font-size: 0.95rem;
  font-weight: 600;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--primary);
  margin-bottom: 16px;
  color: var(--primary);
}
.paper-question { margin-bottom: 20px; padding-left: 8px; }
.pq-header { margin-bottom: 4px; }
.pq-number { font-weight: 700; font-size: 0.95rem; }
.pq-score { color: var(--text-secondary); font-size: 0.85rem; }
.pq-content { margin-bottom: 6px; line-height: 1.8; }
.pq-content img { max-width: 500px; max-height: 300px; border-radius: var(--radius-sm); }
.pq-options { margin-left: 1.5rem; }
.pq-option { margin-bottom: 2px; }
.paper-answers { margin-top: 20px; }
.paper-answers h2 { text-align: center; font-size: 1.2rem; margin-bottom: 12px; color: var(--deep); }
.paper-answers div { margin-bottom: 4px; font-size: 0.92rem; }

/* ── Build Layout ───────────────────────────────────── */
.build-layout {
  display: flex;
  gap: 20px;
  align-items: flex-start;
}
.build-browser {
  flex: 1;
  min-width: 0;
  background: var(--card);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
  overflow: hidden;
}
.build-browser-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
}
.build-browser-header h3 { font-size: 0.95rem; }
.browser-questions {
  padding: 12px 20px;
  max-height: 600px;
  overflow-y: auto;
}
/* browser-filters defined in filter section above */
.browser-pagination { padding: 8px 20px 16px; }

/* ── Build Paper ────────────────────────────────────── */
.build-paper {
  width: 400px;
  min-width: 360px;
  background: var(--card);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--border);
  max-height: 650px;
  display: flex;
  flex-direction: column;
}
.build-paper-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}
.build-paper-header h3 { font-size: 0.95rem; }
.build-paper-header span { font-size: 0.82rem; color: var(--text-secondary); }
.build-paper-header span strong { color: var(--primary); }
.paper-questions {
  padding: 12px 16px;
  overflow-y: auto;
  flex: 1;
}

.pq-card {
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 12px;
  margin-bottom: 8px;
  background: #faf9f7;
}
.pq-card-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}
.pq-order { font-weight: 700; font-size: 0.92rem; }
.pq-type { font-size: 0.78rem; color: var(--primary); }
.pq-card-actions { margin-left: auto; display: flex; align-items: center; gap: 6px; }
.pq-card-body { font-size: 0.82rem; line-height: 1.6; }
.pq-card-body .pq-content { margin-bottom: 4px; }
.pq-card-body .pq-content img { max-width: 200px; max-height: 80px; border-radius: var(--radius-sm); }
.pq-options { margin-left: 1rem; }
.pq-opt { font-size: 0.82rem; }
.pq-answer {
  margin-top: 4px;
  color: var(--success);
  font-size: 0.78rem;
  font-weight: 500;
}

/* ── Dropdown ───────────────────────────────────────── */
.dropdown-toggle { cursor: pointer; position: relative; }
.dropdown-menu {
  display: none;
  position: absolute;
  top: 100%;
  right: 0;
  background: var(--card);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-elevated);
  min-width: 150px;
  z-index: 50;
}
.dropdown-menu.show { display: block; animation: fadeIn var(--duration-fast) var(--ease-out); }
.dropdown-item {
  display: block;
  padding: 8px 16px;
  font-size: 0.88rem;
  color: var(--text);
  transition: background var(--duration-fast);
}
.dropdown-item:hover { background: #f5f4f1; color: var(--primary); }

/* ── Editor Toolbar ─────────────────────────────────── */
.editor-toolbar {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 0 12px;
  background: #faf9f7;
  border: 1.5px solid var(--border-strong);
  border-bottom: none;
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
  flex-wrap: wrap;
  max-height: 0;
  overflow: hidden;
  border-width: 0;
  transition: max-height 0.28s var(--ease-smooth), padding 0.28s var(--ease-smooth), border-width 0.28s var(--ease-smooth);
}
.editor-toolbar.show {
  max-height: 80px;
  padding: 6px 12px;
  border-width: 1.5px;
  border-bottom-width: 0;
}
.editor-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 32px; height: 30px;
  padding: 3px 10px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  background: transparent;
  font-size: 0.88rem;
  cursor: pointer;
  transition: all var(--duration-fast);
  color: var(--text);
}
.editor-btn:hover { background: var(--primary-light); border-color: var(--primary-border); color: var(--primary); }
.editor-btn:active { background: var(--primary-border); }
.editor-sep {
  display: inline-block;
  width: 1px; height: 18px;
  background: var(--border-strong);
  margin: 0 4px;
}

/* ── WYSIWYG Editor ─────────────────────────────────── */
.editor-wysiwyg {
  border: 1.5px solid var(--border-strong);
  border-radius: var(--radius-md);
  padding: 12px 16px;
  background: var(--card);
  min-height: 200px;
  max-height: 500px;
  overflow-y: auto;
  line-height: 1.8;
  font-size: 0.92rem;
  font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  outline: none;
  transition: all var(--duration-fast);
}
.editor-wysiwyg:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(59,130,246,0.1);
}
.editor-wysiwyg[data-show-placeholder]:empty::before,
.editor-wysiwyg[data-show-placeholder]:not(:focus)::before {
  content: attr(data-placeholder);
  color: #ccc;
  pointer-events: none;
}
.editor-wysiwyg img {
  max-width: 100%; max-height: 300px;
  display: block; margin: 8px 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}
.editor-wysiwyg.editor-sm { min-height: 100px; max-height: 300px; }
.editor-wysiwyg.editor-opt { min-height: 60px; max-height: 150px; font-size: 0.88rem; padding: 8px 12px; }

.editor-group .editor-wysiwyg { border-top: none; }

/* ── Knowledge Blank Marking ─────────────────────── */
.kb-fill {
  background: #fef3c7;
  border-bottom: 2px solid #f59e0b;
  padding: 0 2px;
  border-radius: 2px;
  cursor: pointer;
}
.kb-fill:hover { background: #fde68a; }
.kb-blank {
  display: inline-block;
  min-width: 64px;
  border-bottom: 2px solid #000;
  margin: 0 2px;
  color: transparent;
  user-select: none;
}
.editor-wysiwyg.kb-locked {
  background: #f5f5f5;
  cursor: not-allowed;
  opacity: 0.85;
  user-select: none;
}