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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: #F1F5F9;
  color: #111827;
  min-height: 100vh;
}

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

.sidebar {
  width: 220px;
  background: #111827;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  padding: 1.5rem 1rem;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  border-right: 1px solid rgba(255,255,255,0.06);
}

.sidebar-brand {
  display: flex; align-items: center; gap: 0.6rem;
  padding: 0 0.25rem;
  margin-bottom: 2rem;
}
.sidebar-icon {
  width: 32px; height: 32px;
  background: #4F46E5;
  border-radius: 7px;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
  box-shadow: 0 2px 8px rgba(79,70,229,0.45);
}
.sidebar-icon::after {
  content: "✓";
  color: white;
  font-size: 1rem;
  font-weight: 900;
  line-height: 1;
}
.sidebar-title {
  font-size: 0.92rem;
  font-weight: 800;
  color: #F9FAFB;
  letter-spacing: 0.5px;
}

.sidebar nav { display: flex; flex-direction: column; gap: 0.2rem; }

.nav-link {
  display: flex; align-items: center; gap: 0.6rem;
  padding: 0.55rem 0.75rem;
  border-radius: 6px;
  color: #C4C9D4;
  font-size: 0.82rem;
  font-weight: 500;
  text-decoration: none;
  transition: background 0.15s, color 0.15s;
}
.nav-link:hover { background: rgba(255,255,255,0.08); color: #F9FAFB; }
.nav-link.active {
  background: rgba(99,102,241,0.18);
  color: #A5B4FC;
  font-weight: 600;
}
.nav-link .nav-dot {
  width: 5px; height: 5px;
  border-radius: 50%;
  background: currentColor;
  flex-shrink: 0;
  opacity: 0.7;
}
.nav-link.active .nav-dot { opacity: 1; }

.main {
  flex: 1;
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
  min-width: 0;
}

/* 所有直接子元素水平置中，最寬 660px */
.main > * {
  width: 100%;
  max-width: 660px;
  margin-left: auto;
  margin-right: auto;
}

/* 考生管理頁：較寬內容，最寬 860px */
.main-wide > * {
  max-width: 860px;
}

/* ── Cards ── */
.card {
  background: white;
  border-radius: 10px;
  border: 1px solid #E5E7EB;
  box-shadow: 0 1px 4px rgba(0,0,0,0.06);
  padding: 1.4rem 1.5rem;
  margin-bottom: 0.9rem;
}
.card-top-accent { border-top: 3px solid #4F46E5; }

/* ── Step badge ── */
.step-badge {
  display: inline-block;
  background: #4F46E5;
  color: white;
  border-radius: 3px;
  padding: 1px 7px;
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 1px;
  margin-right: 0.5rem;
}

.step-header {
  display: flex; align-items: center;
  margin-bottom: 1rem;
  font-size: 0.85rem;
  font-weight: 700;
  color: #111827;
}

/* ── Form elements ── */
input[type="text"], select {
  width: 100%;
  padding: 0.55rem 0.75rem;
  border: 1px solid #E5E7EB;
  border-radius: 7px;
  font-size: 0.875rem;
  color: #111827;
  background: white;
  outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
}
input[type="text"]:focus, select:focus {
  border-color: #4F46E5;
  box-shadow: 0 0 0 3px rgba(79,70,229,0.12);
}
input::placeholder { color: #9CA3AF; }

.field-label {
  font-size: 0.68rem;
  font-weight: 700;
  color: #6B7280;
  letter-spacing: 0.8px;
  text-transform: uppercase;
  margin-bottom: 0.5rem;
}
.field-hint {
  font-size: 0.74rem;
  color: #9CA3AF;
  margin-top: 0.4rem;
}

/* ── Buttons ── */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 0.6rem 1.25rem;
  border-radius: 7px;
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: opacity 0.15s, transform 0.1s, box-shadow 0.15s;
  text-decoration: none;
}
.btn:active { transform: scale(0.98); }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }
.btn-primary {
  background: linear-gradient(135deg, #4F46E5 0%, #6366F1 100%);
  color: white;
  box-shadow: 0 2px 8px rgba(79,70,229,0.3);
}
.btn-primary:hover:not(:disabled) {
  background: linear-gradient(135deg, #4338CA 0%, #4F46E5 100%);
  box-shadow: 0 4px 12px rgba(79,70,229,0.4);
}
.btn-ghost {
  background: transparent;
  color: #6B7280;
  border: 1px solid #E5E7EB;
}
.btn-ghost:hover { background: #F9FAFB; }
.btn-full { width: 100%; }
.btn-sm { padding: 0.35rem 0.8rem; font-size: 0.78rem; }

/* ── Checkbox group ── */
.checkbox-group { display: flex; flex-direction: column; gap: 0.4rem; }
.checkbox-item {
  display: flex; align-items: flex-start; gap: 0.6rem;
  padding: 0.75rem 0.75rem;
  border: 1px solid #E5E7EB;
  border-radius: 7px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s, box-shadow 0.15s;
  font-size: 0.875rem;
}
.checkbox-item:hover { border-color: #4F46E5; background: #F5F3FF; }
.checkbox-item.checked {
  border-color: #4F46E5;
  background: #F5F3FF;
  box-shadow: 0 0 0 3px rgba(79,70,229,0.08);
}
.checkbox-item input[type="checkbox"] { accent-color: #4F46E5; margin-top: 0.25rem; }

.unit-info-wrapper {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}
.unit-tag {
  font-size: 0.65rem;
  font-weight: 800;
  color: #4F46E5;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.unit-title {
  font-size: 0.88rem;
  font-weight: 600;
  color: #111827;
  line-height: 1.4;
}

.select-all-row {
  display: flex; justify-content: flex-end;
  margin-bottom: 0.5rem;
}
.unit-count { font-size: 0.74rem; color: #6B7280; margin-top: 0.4rem; }

/* ── Radio options (quiz) ── */
.options-list { display: flex; flex-direction: column; gap: 0.5rem; }

.option-item {
  display: flex; align-items: center; gap: 0.75rem;
  padding: 0.8rem 1rem;
  border: 1.5px solid #E5E7EB;
  border-radius: 9px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s, box-shadow 0.15s;
  font-size: 0.9rem;
  color: #374151;
}
.option-item:hover {
  border-color: #4F46E5;
  background: #F5F3FF;
  box-shadow: 0 0 0 3px rgba(79,70,229,0.08);
}
.option-item.selected {
  border-color: #4F46E5;
  background: #F5F3FF;
  box-shadow: 0 0 0 3px rgba(79,70,229,0.1);
}
.option-item.correct { border-color: #10B981; background: #ECFDF5; color: #065F46; }
.option-item.wrong { border-color: #EF4444; background: #FEF2F2; color: #991B1B; }

.option-letter {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: #F3F4F6;
  display: flex; align-items: center; justify-content: center;
  font-weight: 700;
  font-size: 0.78rem;
  flex-shrink: 0;
  transition: background 0.15s, color 0.15s;
}
.option-item.selected .option-letter { background: #4F46E5; color: white; }
.option-item.correct .option-letter { background: #10B981; color: white; }
.option-item.wrong .option-letter { background: #EF4444; color: white; }

/* ── Progress bar ── */
.progress-bar-track {
  width: 100%; height: 4px;
  background: #E5E7EB;
  border-radius: 2px;
  margin-top: 0.6rem;
}
.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, #4F46E5, #6366F1);
  border-radius: 2px;
  transition: width 0.3s ease;
}

/* ── User bar ── */
.user-bar {
  display: flex; align-items: center; justify-content: space-between;
  background: white;
  border-radius: 10px;
  border: 1px solid #E5E7EB;
  box-shadow: 0 1px 4px rgba(0,0,0,0.06);
  padding: 0.6rem 1rem;
  margin-bottom: 1.5rem;
}
.user-avatar {
  width: 28px; height: 28px;
  border-radius: 6px;
  background: linear-gradient(135deg, #4F46E5, #6366F1);
  color: white;
  display: flex; align-items: center; justify-content: center;
  font-weight: 700;
  font-size: 0.75rem;
  flex-shrink: 0;
}
.user-info { display: flex; align-items: center; gap: 0.6rem; }
.user-name { font-weight: 700; font-size: 0.85rem; color: #111827; }
.user-label { font-size: 0.68rem; color: #9CA3AF; }
.status-dot {
  display: flex; align-items: center; gap: 0.4rem;
  font-size: 0.7rem; font-weight: 600; color: #6B7280;
}
.status-dot::before {
  content: "";
  width: 6px; height: 6px;
  border-radius: 50%;
  background: #10B981;
  display: inline-block;
}

/* ── Score donut ── */
.score-card { text-align: center; padding: 2rem 1.5rem 1.5rem; }
.donut-wrap { display: flex; justify-content: center; margin-bottom: 1.2rem; }
.donut {
  width: 150px; height: 150px;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
}
.donut-inner {
  width: 112px; height: 112px;
  border-radius: 50%;
  background: white;
  display: flex; flex-direction: column;
  align-items: center; justify-content: center;
}
.donut-score { font-size: 1.6rem; font-weight: 800; color: #111827; line-height: 1.1; }
.donut-pct { font-size: 0.88rem; font-weight: 700; }

.score-stats {
  display: flex;
  background: #F9FAFB;
  border-radius: 8px;
  border: 1px solid #E5E7EB;
  overflow: hidden;
  max-width: 300px;
  margin: 1rem auto 0;
}
.score-stat {
  flex: 1; text-align: center; padding: 0.8rem 0;
  border-right: 1px solid #E5E7EB;
}
.score-stat:last-child { border-right: none; }
.score-stat-val { font-size: 1.15rem; font-weight: 800; }
.score-stat-lbl {
  font-size: 0.68rem; color: #6B7280;
  margin-top: 2px; text-transform: uppercase; letter-spacing: 0.4px;
}

/* ── Weakness card ── */
.weakness-card {
  border-left: 3px solid #F59E0B;
}
.weakness-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.5rem 0;
  border-bottom: 1px solid #F3F4F6;
}
.weakness-item:last-child { border-bottom: none; }
.weakness-unit { font-weight: 600; font-size: 0.84rem; }
.weakness-sub { font-size: 0.7rem; color: #6B7280; margin-top: 1px; }
.weakness-pct { font-weight: 700; font-size: 0.9rem; }
.weakness-hint {
  margin-top: 0.8rem;
  font-size: 0.78rem;
  color: #6B7280;
  background: #F9FAFB;
  border-radius: 5px;
  padding: 0.5rem 0.7rem;
  border: 1px solid #E5E7EB;
}

/* ── Answer review ── */
.review-item {
  border-radius: 0 8px 8px 0;
  padding: 0.9rem 1.1rem;
  margin-bottom: 0.8rem;
  border-top: 1px solid #E5E7EB;
  border-right: 1px solid #E5E7EB;
  border-bottom: 1px solid #E5E7EB;
}
.review-item.wrong-item { background: white; border-left: 3px solid #EF4444; }
.review-item.correct-item { background: white; border-left: 3px solid #10B981; }

.review-tag {
  display: inline-block;
  color: white;
  border-radius: 3px;
  padding: 1px 5px;
  font-size: 0.62rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  margin-right: 0.4rem;
}
.review-q { font-size: 0.87rem; font-weight: 500; line-height: 1.65; margin: 0.4rem 0 0.6rem; }
.review-answer { font-size: 0.81rem; margin-bottom: 0.2rem; }
.review-explanation {
  font-size: 0.8rem;
  color: #374151;
  background: #F8FAFC;
  border-radius: 5px;
  padding: 0.5rem 0.7rem;
  margin-top: 0.5rem;
  border: 1px solid #E5E7EB;
  line-height: 1.65;
}

/* ── Expandable section ── */
.expandable { margin-bottom: 0.8rem; }
.expandable-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.75rem 1rem;
  background: white;
  border: 1px solid #E5E7EB;
  border-radius: 10px;
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 600;
  color: #374151;
  user-select: none;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
  transition: background 0.15s;
}
.expandable-header:hover { background: #F9FAFB; }
.expandable-header .chevron {
  transition: transform 0.2s;
  color: #9CA3AF;
}
.expandable-header.open .chevron { transform: rotate(180deg); }
.expandable-body { display: none; padding-top: 0.5rem; }
.expandable-body.open { display: block; }

/* ── Nav row (quiz prev/next) ── */
.nav-row {
  display: flex; align-items: center; gap: 0.75rem;
  margin-top: 1rem;
}
.nav-row .nav-center {
  flex: 1; text-align: center;
  font-size: 0.75rem; color: #9CA3AF;
}

/* ── Section header (dashboard) ── */
.section-header {
  display: flex; align-items: center; gap: 0.5rem;
  margin: 0 0 0.9rem;
}
.section-bar {
  width: 3px; height: 18px;
  background: #6366F1;
  border-radius: 2px;
  flex-shrink: 0;
}
.section-title { font-size: 0.9rem; font-weight: 700; color: #0F172A; }

/* ── Table ── */
table { width: 100%; border-collapse: collapse; font-size: 0.83rem; }
th {
  text-align: left; padding: 0.5rem 0.75rem;
  font-size: 0.68rem; font-weight: 700; color: #6B7280;
  text-transform: uppercase; letter-spacing: 0.5px;
  border-bottom: 1px solid #E5E7EB;
}
td { padding: 0.6rem 0.75rem; border-bottom: 1px solid #F3F4F6; color: #374151; }
tr:last-child td { border-bottom: none; }

/* ── Badge ── */
.badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.68rem;
  font-weight: 600;
}
.badge-green { background: #ECFDF5; color: #059669; }
.badge-yellow { background: #FFFBEB; color: #D97706; }
.badge-red { background: #FEF2F2; color: #DC2626; }

/* ── Chart container ── */
.chart-container { position: relative; height: 220px; }

/* ── Empty state ── */
.empty-state {
  text-align: center;
  padding: 2.5rem 1.5rem;
  color: #9CA3AF;
}
.empty-state p { font-size: 0.875rem; margin-top: 0.5rem; }

/* ── Toast ── */
.toast {
  position: fixed; bottom: 1.5rem; right: 1.5rem;
  background: #1F2937; color: white;
  padding: 0.7rem 1.1rem;
  border-radius: 8px;
  font-size: 0.83rem;
  font-weight: 500;
  z-index: 999;
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.2s, transform 0.2s;
  pointer-events: none;
}
.toast.show { opacity: 1; transform: translateY(0); }

/* ── Context card (group question) ── */
.context-card {
  background: #F8FAFC;
  border-radius: 7px;
  padding: 0.9rem 1.1rem;
  border: 1px solid #E5E7EB;
  border-left: 3px solid #6B7280;
  margin-bottom: 0.6rem;
}
.context-tag {
  display: inline-block;
  background: #6B7280; color: white;
  border-radius: 3px; padding: 1px 6px;
  font-size: 0.62rem; font-weight: 700; letter-spacing: 0.5px;
  margin-right: 0.4rem;
}
.context-label { font-size: 0.68rem; color: #9CA3AF; text-transform: uppercase; letter-spacing: 0.5px; }
.context-text { font-size: 0.87rem; color: #374151; line-height: 1.65; margin-top: 0.4rem; }

/* ── Loading ── */
.loading {
  display: flex; align-items: center; justify-content: center;
  height: 120px; color: #9CA3AF; font-size: 0.875rem;
}

/* ── Mastery mode ── */
.mastery-dots {
  display: flex; flex-wrap: wrap; gap: 5px;
  margin: 0.55rem 0 0.3rem;
}
.mastery-dot {
  width: 11px; height: 11px;
  border-radius: 50%;
  background: #E5E7EB;
  flex-shrink: 0;
  transition: background 0.25s;
}
.mastery-dot.current {
  background: #6366F1;
  box-shadow: 0 0 0 2.5px rgba(99,102,241,0.3);
}
.mastery-dot.retried  { background: #FCA5A5; }
.mastery-dot.mastered { background: #6EE7B7; }

.retry-badge {
  display: inline-flex; align-items: center; gap: 0.3rem;
  background: #FEF3C7; color: #92400E;
  border: 1px solid #FDE68A;
  border-radius: 5px; padding: 2px 9px;
  font-size: 0.72rem; font-weight: 700;
}

.mastery-explanation {
  font-size: 0.8rem; color: #374151;
  background: #EEF2FF; border-radius: 6px;
  padding: 0.55rem 0.8rem; margin-top: 0.75rem;
  border: 1px solid #C7D2FE; line-height: 1.65;
}

/* ── Topic tabs (dashboard analytics) ── */
.topic-tab {
  padding: 0.35rem 0.85rem;
  border-radius: 20px;
  border: 1.5px solid #E5E7EB;
  background: white;
  font-size: 0.78rem;
  font-weight: 600;
  color: #6B7280;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s, color 0.15s;
}
.topic-tab:hover { border-color: #4F46E5; color: #4F46E5; background: #F5F3FF; }
.topic-tab--active {
  border-color: #4F46E5;
  background: #4F46E5;
  color: white;
}

/* ── Dashboard grid helpers ── */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(4,1fr);
  gap: 0.75rem;
  margin-bottom: 1rem;
}
.weakness-cols {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 0.75rem;
}
#sessions-content { overflow-x: auto; }

/* ── Responsive ── */
@media (max-width: 768px) {
  .layout { flex-direction: column; }

  .sidebar {
    width: 100%;
    height: auto;
    min-height: 0;
    flex-direction: row;
    align-items: center;
    padding: 0.6rem 1rem;
    position: sticky;
    top: 0;
    z-index: 100;
    border-right: none;
    border-bottom: 1px solid rgba(255,255,255,0.08);
    overflow-y: visible;
  }
  .sidebar-brand { margin-bottom: 0; flex-shrink: 0; }
  .sidebar nav { flex-direction: row; gap: 0.25rem; margin-left: auto; }
  .nav-link { padding: 0.4rem 0.65rem; font-size: 0.78rem; }

  /* .main 不讓子內容橫向撐破整頁（防止 navbar 一起滑動） */
  /* width: 100% 確保在 column flex + align-items:flex-start 下仍填滿橫向 */
  .main { padding: 1rem; min-height: auto; overflow-x: hidden; width: 100%; }
  /* 考生管理頁內容很長，不設最低高度 */
  .main-wide { min-height: auto; }
  .main > *, .main-wide > * { max-width: 100%; }

  /* 首頁：登入卡佔滿畫面並置中 */
  #view-login {
    min-height: calc(100vh - 52px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
  }
  #view-login > * {
    width: 100%;
    max-width: 360px;
  }

  /* Quiz 進度卡 badge 防止長主題名稱 overflow */
  #q-badges { flex-wrap: wrap; justify-content: flex-end; max-width: 55%; }
  #q-badges span { max-width: 140px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

  /* Dashboard 響應式格線 */
  .metrics-grid { grid-template-columns: repeat(2,1fr); }
  .weakness-cols { grid-template-columns: 1fr; }
}