* { box-sizing: border-box; }
:root {
  --bg: #f4f7fb;
  --card: rgba(255,255,255,.88);
  --text: #172033;
  --muted: #667085;
  --line: #e7ecf3;
  --primary: #2563eb;
  --primary-soft: #e8f0ff;
  --success: #16a34a;
  --success-soft: #ecfdf3;
  --danger: #dc2626;
  --danger-soft: #fef2f2;
  --gold: #d97706;
  --gold-soft: #fff7ed;
  --shadow: 0 20px 50px rgba(18, 38, 63, .08);
}
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  background: radial-gradient(circle at top left, #eef4ff 0, #f8fbff 28%, var(--bg) 60%);
  color: var(--text);
}
a { color: var(--primary); text-decoration: none; }
pre { white-space: pre-wrap; word-break: break-word; font-family: inherit; line-height: 1.8; }
button, input, select, summary { font: inherit; }
.app-shell { display: flex; min-height: 100vh; }
.sidebar {
  width: 260px;
  background: linear-gradient(180deg, #0f172a 0%, #111827 100%);
  color: #fff;
  padding: 24px 18px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  position: sticky;
  top: 0;
  height: 100vh;
}
.brand-wrap { display: flex; align-items: center; gap: 12px; }
.brand-badge {
  width: 42px; height: 42px; border-radius: 14px;
  display: grid; place-items: center;
  background: linear-gradient(135deg, #60a5fa, #2563eb);
  font-weight: 800;
}
.brand { font-size: 22px; font-weight: 800; letter-spacing: .5px; }
.brand-sub { font-size: 12px; color: #94a3b8; margin-top: 2px; }
.sidebar nav { display: flex; flex-direction: column; gap: 8px; }
.sidebar nav a {
  color: #d1d5db;
  padding: 12px 14px;
  border-radius: 12px;
  transition: .18s ease;
}
.sidebar nav a:hover { background: rgba(255,255,255,.08); color: #fff; }
.sidebar-btn { width: 100%; }
.main-content { flex: 1; padding: 28px; max-width: 1400px; width: 100%; margin: 0 auto; }
.main-content.full { display: flex; align-items: center; justify-content: center; max-width: none; }
.page-header { display: flex; align-items: flex-start; justify-content: space-between; gap: 20px; margin-bottom: 20px; }
.page-header-stack { flex-direction: column; }
.practice-header { gap: 12px; }
.eyebrow { color: var(--primary); font-size: 12px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; margin-bottom: 8px; }
.card {
  background: var(--card);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255,255,255,.65);
  border-radius: 22px;
  padding: 22px;
  box-shadow: var(--shadow);
  margin-bottom: 20px;
}
.card-subtle {
  background: #f8fbff;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 12px 14px;
}
.hero-card {
  display: flex; justify-content: space-between; gap: 24px; align-items: center;
  padding: 28px; border-radius: 26px; margin-bottom: 22px;
  background: linear-gradient(135deg, #ffffff 0%, #eef5ff 100%);
  box-shadow: var(--shadow);
  border: 1px solid rgba(255,255,255,.72);
}
.hero-card h1 { margin: 0 0 10px; font-size: clamp(28px, 4vw, 42px); }
.hero-card p { margin: 0; color: var(--muted); line-height: 1.8; max-width: 700px; }
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }
.primary-link, button {
  border: 0; background: linear-gradient(135deg, #3b82f6, #2563eb); color: #fff;
  padding: 12px 18px; border-radius: 14px; cursor: pointer; font-size: 14px; font-weight: 700;
  box-shadow: 0 10px 24px rgba(37,99,235,.22);
}
.ghost-btn, .ghost-link {
  border: 0; background: var(--primary-soft); color: #1d4ed8;
  padding: 12px 16px; border-radius: 14px; cursor: pointer; font-size: 14px; font-weight: 600;
}
.text-link { color: var(--muted); font-size: 14px; }
.stats-grid, .split-grid, .quick-grid { display: grid; gap: 16px; margin-bottom: 20px; }
.stats-grid { grid-template-columns: repeat(4, minmax(0,1fr)); }
.secondary-stats-grid { grid-template-columns: repeat(2, minmax(0,1fr)); }
.split-grid { grid-template-columns: repeat(2, minmax(0,1fr)); }
.quick-grid { grid-template-columns: repeat(5, minmax(0,1fr)); }
.stat span { display: block; color: var(--muted); margin-bottom: 8px; }
.stat strong { font-size: clamp(28px, 3vw, 40px); }
.accent-blue { background: linear-gradient(180deg, #ffffff, #eff6ff); }
.accent-green { background: linear-gradient(180deg, #ffffff, #ecfdf5); }
.accent-red { background: linear-gradient(180deg, #ffffff, #fef2f2); }
.accent-gold { background: linear-gradient(180deg, #ffffff, #fff7ed); }
.quick-card {
  display: block; padding: 20px; border-radius: 20px; background: #fff; color: var(--text);
  border: 1px solid var(--line); box-shadow: var(--shadow);
}
.quick-title { font-size: 18px; font-weight: 800; margin-bottom: 8px; }
.quick-desc { color: var(--muted); line-height: 1.7; }
.simple-list, .question-list { list-style: none; padding: 0; margin: 0; }
.simple-list li, .question-list li { display: flex; justify-content: space-between; gap: 16px; padding: 12px 0; border-bottom: 1px solid var(--line); }
.question-list.compact li { display: block; }
.meta { font-size: 12px; color: var(--muted); margin-bottom: 6px; }
.question-layout { display: grid; grid-template-columns: 280px minmax(0, 1fr); gap: 20px; align-items: start; }
.question-side { position: sticky; top: 24px; }
.mobile-secondary-panel { order: 1; }
.question-main { min-width: 0; order: 2; }
.side-section + .side-section { margin-top: 20px; }
.side-label { color: var(--muted); font-size: 13px; margin-bottom: 8px; }
.side-value { font-size: 32px; font-weight: 800; }
.side-hint, .micro-tip { color: var(--muted); font-size: 13px; line-height: 1.7; }
.progress-track { width: 100%; height: 10px; background: #eaf0f7; border-radius: 999px; overflow: hidden; margin: 12px 0 8px; }
.progress-bar { height: 100%; background: linear-gradient(90deg, #60a5fa, #2563eb); border-radius: 999px; }
.meta-kv { display: flex; justify-content: space-between; gap: 12px; padding: 8px 0; border-bottom: 1px dashed var(--line); }
.meta-kv span { color: var(--muted); }
.side-actions { display: grid; gap: 12px; }
.wide { display: block; text-align: center; }
.question-card h2 { margin-top: 12px; line-height: 1.9; font-size: clamp(20px, 2.3vw, 28px); }
.question-topbar { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.mobile-progress { display: none; margin-bottom: 14px; }
.options-wrap { display: flex; flex-direction: column; gap: 14px; margin: 24px 0; }
.option-item { display: flex; align-items: flex-start; gap: 12px; padding: 14px 16px; border: 1px solid #dbe4f0; border-radius: 16px; background: #f8fafc; }
.option-card:hover { border-color: #a5c4ff; background: #f5f9ff; }
.option-item input { margin-top: 4px; transform: scale(1.15); }
.action-row, .secondary-actions, .pill-row, .card-title-row, .jump-form { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.wrap-gap { gap: 10px; }
.toolbar-panel { width: 100%; margin-top: 12px; }
.toolbar-grid {
  display: grid; gap: 12px; grid-template-columns: repeat(4, minmax(0,1fr));
  background: rgba(255,255,255,.75); padding: 14px; border: 1px solid var(--line); border-radius: 18px;
}
.toolbar-grid-5 { grid-template-columns: repeat(5, minmax(0,1fr)); }
.toolbar-grid label { display: flex; flex-direction: column; gap: 8px; color: var(--muted); font-size: 13px; }
.toolbar-submit { display: flex; align-items: end; }
.toolbar-collapse {
  width: 100%; background: rgba(255,255,255,.76); border: 1px solid var(--line); border-radius: 16px; padding: 0 14px;
}
.toolbar-collapse summary {
  cursor: pointer; list-style: none; padding: 14px 0; font-weight: 700; color: #334155;
}
.toolbar-collapse summary::-webkit-details-marker { display: none; }
input[type="password"], input[type="number"], select {
  width: 100%; padding: 12px 14px; border-radius: 14px; border: 1px solid #cbd5e1; background: #fff;
}
.login-wrap { width: 100%; display: flex; align-items: center; justify-content: center; padding: 24px; }
.login-card {
  width: 100%; max-width: 460px; background: rgba(255,255,255,.88); border-radius: 28px; padding: 30px;
  box-shadow: 0 24px 60px rgba(15,23,42,.12); border: 1px solid rgba(255,255,255,.75);
}
.login-card h1 { margin: 0 0 8px; }
.login-card p { color: var(--muted); line-height: 1.8; }
.login-card form { display: flex; flex-direction: column; gap: 12px; }
.result-box { margin-top: 16px; padding: 16px; border-radius: 16px; background: #f8fafc; line-height: 1.9; }
.result-box.ok { background: var(--success-soft); border: 1px solid #a7f3d0; }
.result-box.bad { background: var(--danger-soft); border: 1px solid #fecaca; }
.llm-box { background: #f8fbff; }
.memorize-box { background: #fffbea; border: 1px solid #fde68a; }
.memorize-box.soft { background: #fcfcfd; border: 1px dashed #d4dbe6; }
.answer-toggle summary { cursor: pointer; font-weight: 700; }
.answer-toggle-body { margin-top: 12px; line-height: 1.9; }
.empty { text-align: center; color: var(--muted); }
.pill { display: inline-flex; padding: 5px 10px; border-radius: 999px; background: #dbeafe; color: #1d4ed8; font-size: 12px; font-weight: 700; }
.pill.danger { background: #fee2e2; color: #b91c1c; }
.pill.gold { background: #ffedd5; color: #b45309; }
.pill.success { background: #dcfce7; color: #15803d; }
.alert { padding: 12px 14px; border-radius: 12px; margin-bottom: 12px; }
.alert.error { background: #fef2f2; color: #b91c1c; }
.alert.success { background: #ecfdf5; color: #166534; }
.logout-form { margin-top: auto; }
.settings-card { max-width: 860px; }
.settings-form { display: grid; gap: 16px; }
.setting-item {
  display: flex; align-items: center; justify-content: space-between; gap: 20px;
  padding: 18px; border: 1px solid var(--line); border-radius: 18px; background: #fbfdff;
}
.setting-item span { display: flex; flex-direction: column; gap: 6px; }
.setting-item small { color: var(--muted); line-height: 1.7; }
.setting-item input[type="checkbox"] { width: 22px; height: 22px; }
.jump-card { padding-top: 16px; }
.full-width-form { width: 100%; }
.jump-label { font-weight: 700; }
.jump-inline { display: flex; gap: 12px; align-items: center; margin-top: 10px; }
.jump-two-cols { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 16px; }
.sticky-actions { position: sticky; bottom: 12px; background: linear-gradient(180deg, rgba(255,255,255,.6), rgba(255,255,255,.96)); padding-top: 8px; }
@media (max-width: 1180px) {
  .question-layout { grid-template-columns: 1fr; }
  .question-side { position: static; }
  .quick-grid { grid-template-columns: repeat(2, minmax(0,1fr)); }
  .stats-grid { grid-template-columns: repeat(2, minmax(0,1fr)); }
  .toolbar-grid, .toolbar-grid-5 { grid-template-columns: repeat(2, minmax(0,1fr)); }
  .jump-two-cols { grid-template-columns: 1fr; }
}
@media (max-width: 960px) {
  .app-shell { flex-direction: column; }
  .sidebar { width: 100%; height: auto; position: static; }
  .split-grid { grid-template-columns: 1fr; }
  .page-header, .hero-card, .question-topbar { flex-direction: column; align-items: flex-start; }
  .mobile-priority-question { display: flex; flex-direction: column; }
  .question-main { order: 1; }
  .mobile-secondary-panel { order: 2; }
  .mobile-progress { display: block; }
  .desktop-only-progress { display: none; }
}
@media (max-width: 640px) {
  .main-content { padding: 12px; }
  .card, .hero-card, .login-card { padding: 16px; border-radius: 16px; }
  .stats-grid, .quick-grid, .toolbar-grid, .toolbar-grid-5, .secondary-stats-grid { grid-template-columns: 1fr; }
  .setting-item { flex-direction: column; align-items: flex-start; }
  .jump-inline, .action-row, .secondary-actions { flex-direction: column; align-items: stretch; }
  .primary-link, .ghost-link, .ghost-btn, button { width: 100%; text-align: center; }
  .question-card h2 { font-size: 22px; line-height: 1.8; }
  .question-topbar { align-items: stretch; }
  .pill-row { gap: 8px; }
  .toolbar-collapse { order: 2; }
  .toolbar-collapse summary { padding: 12px 0; }
  .practice-header > div:first-child p { margin-bottom: 0; }
  .sticky-actions { position: static; background: transparent; padding-top: 0; }
  .jump-card, .mobile-secondary-panel { margin-top: 0; }
}