:root {
  color-scheme: light;
  --surface-1:      #fcfcfb;
  --surface-2:      #ffffff;
  --page-plane:     #f2f3f6;
  --text-primary:   #0b0b0b;
  --text-secondary: #52514e;
  --text-muted:     #898781;
  --gridline:       #e1e0d9;
  --border:         rgba(11,11,11,0.10);
  --border-strong:  rgba(11,11,11,0.16);

  --brand-blue:     #2a78d6;
  --brand-blue-dk:  #184f95;

  --good:     #0ca30c;
  --good-bg:  #e7f7e7;
  --warning:  #c98500;
  --warning-bg: #fdf1d9;
  --serious:  #ec835a;
  --critical: #d03b3b;
  --critical-bg: #fbe7e6;

  --series-2-green:  #008300;
  --series-8-red:    #e34948;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --shadow-1: 0 1px 2px rgba(11,11,11,0.04), 0 2px 8px rgba(11,11,11,0.05);
  --shadow-2: 0 4px 14px rgba(11,11,11,0.08), 0 1px 3px rgba(11,11,11,0.06);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --surface-1:      #1a1a19;
    --surface-2:      #212120;
    --page-plane:     #0d0d0d;
    --text-primary:   #ffffff;
    --text-secondary: #c3c2b7;
    --text-muted:     #898781;
    --gridline:       #2c2c2a;
    --border:         rgba(255,255,255,0.10);
    --border-strong:  rgba(255,255,255,0.18);

    --brand-blue:     #3987e5;
    --brand-blue-dk:  #86b6ef;

    --good:     #0ca30c;
    --good-bg:  rgba(12,163,12,0.14);
    --warning:  #fab219;
    --warning-bg: rgba(250,178,25,0.14);
    --serious:  #ec835a;
    --critical: #e66767;
    --critical-bg: rgba(230,103,103,0.16);

    --shadow-1: 0 1px 2px rgba(0,0,0,0.25), 0 2px 8px rgba(0,0,0,0.25);
    --shadow-2: 0 4px 14px rgba(0,0,0,0.35), 0 1px 3px rgba(0,0,0,0.3);
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --surface-1:      #1a1a19;
  --surface-2:      #212120;
  --page-plane:     #0d0d0d;
  --text-primary:   #ffffff;
  --text-secondary: #c3c2b7;
  --text-muted:     #898781;
  --gridline:       #2c2c2a;
  --border:         rgba(255,255,255,0.10);
  --border-strong:  rgba(255,255,255,0.18);
  --brand-blue:     #3987e5;
  --brand-blue-dk:  #86b6ef;
  --good:     #0ca30c;
  --good-bg:  rgba(12,163,12,0.14);
  --warning:  #fab219;
  --warning-bg: rgba(250,178,25,0.14);
  --serious:  #ec835a;
  --critical: #e66767;
  --critical-bg: rgba(230,103,103,0.16);
  --shadow-1: 0 1px 2px rgba(0,0,0,0.25), 0 2px 8px rgba(0,0,0,0.25);
  --shadow-2: 0 4px 14px rgba(0,0,0,0.35), 0 1px 3px rgba(0,0,0,0.3);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
[hidden] { display: none !important; }
body {
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  background: var(--page-plane);
  color: var(--text-primary);
  line-height: 1.5;
}

/* ---------- Topbar ---------- */
.topbar {
  background: var(--surface-2);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-1);
}
.topbar-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 18px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.brand { display: flex; align-items: center; gap: 16px; }
.logo { height: 48px; width: auto; object-fit: contain; }
.logo-secondary { height: 40px; opacity: 0.9; }
.brand-text h1 { font-size: 1.25rem; margin: 0; font-weight: 700; }
.brand-text p { margin: 2px 0 0; color: var(--text-secondary); font-size: 0.85rem; }

main { max-width: 1200px; margin: 0 auto; padding: 32px 24px 80px; }

/* ---------- Upload screen ---------- */
.upload-screen { display: flex; justify-content: center; padding-top: 40px; }
.upload-card {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-2);
  max-width: 560px;
  width: 100%;
  padding: 40px;
  text-align: center;
}
.upload-icon { font-size: 2.5rem; margin-bottom: 8px; }
.upload-card h2 { margin: 0 0 8px; font-size: 1.5rem; }
.muted { color: var(--text-secondary); font-size: 0.92rem; }

.dropzone {
  margin-top: 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  border: 2px dashed var(--border-strong);
  border-radius: var(--radius-md);
  padding: 36px 20px;
  cursor: pointer;
  transition: border-color .15s ease, background .15s ease;
}
.dropzone:hover, .dropzone.dragover {
  border-color: var(--brand-blue);
  background: color-mix(in srgb, var(--brand-blue) 6%, transparent);
}
.dropzone input[type="file"] { display: none; }
.dropzone-icon { font-size: 1.8rem; }
.dropzone-text { font-size: 0.95rem; }
.dropzone-hint { font-size: 0.78rem; color: var(--text-muted); }

.file-status {
  margin-top: 18px;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  text-align: left;
}
.file-status.error { background: var(--critical-bg); color: var(--critical); }
.file-status.ok { background: var(--good-bg); color: var(--good); }

/* ---------- Answer key screen ---------- */
.answer-key-screen { display: flex; justify-content: center; }
.card {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-2);
  max-width: 800px;
  width: 100%;
  padding: 36px;
}
.card h2 { margin-top: 0; }
.answer-key-list { display: flex; flex-direction: column; gap: 14px; margin-top: 20px; }
.answer-key-item {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface-1);
}
.answer-key-item .q-text { flex: 1; font-size: 0.92rem; }
.answer-key-item input {
  width: 160px;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--surface-2);
  color: var(--text-primary);
  font-size: 0.9rem;
}
.actions-row { display: flex; justify-content: space-between; margin-top: 28px; gap: 12px; }

/* ---------- Buttons ---------- */
.btn {
  font-family: inherit;
  font-size: 0.92rem;
  font-weight: 600;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .05s ease, filter .15s ease;
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--brand-blue); color: #fff; }
.btn-primary:hover { filter: brightness(1.08); }
.btn-secondary { background: var(--good); color: #fff; }
.btn-secondary:hover { filter: brightness(1.08); }
.btn-ghost { background: transparent; color: var(--text-primary); border-color: var(--border-strong); }
.btn-ghost:hover { background: var(--surface-1); }

.link-btn {
  display: inline-block;
  margin-top: 16px;
  background: none;
  border: none;
  font-family: inherit;
  font-size: 0.82rem;
  color: var(--text-muted);
  cursor: pointer;
  text-decoration: underline;
}
.link-btn:hover { color: var(--critical); }

.saved-info { font-size: 0.8rem; color: var(--text-muted); }

/* ---------- Report toolbar ---------- */
.report-toolbar {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}
.toolbar-search { flex: 1; min-width: 200px; }
.toolbar-search input {
  width: 100%;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--surface-2);
  color: var(--text-primary);
  font-size: 0.9rem;
}

/* ---------- Filter bar (slicers) ---------- */
.filter-panel {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-1);
  padding: 12px 16px;
  margin-bottom: 20px;
}
.filter-panel-label { font-size: 0.82rem; font-weight: 600; color: var(--text-secondary); }
.filter-bar { display: flex; flex-wrap: wrap; gap: 10px; flex: 1; }
.btn-sm { padding: 6px 12px; font-size: 0.8rem; }

.slicer { position: relative; }
.slicer-btn {
  display: flex; align-items: center; gap: 6px;
  font-family: inherit;
  font-size: 0.84rem;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--surface-1);
  color: var(--text-primary);
  cursor: pointer;
}
.slicer-btn:hover { background: var(--page-plane); }
.slicer-btn.active { border-color: var(--brand-blue); color: var(--brand-blue); background: color-mix(in srgb, var(--brand-blue) 8%, transparent); }
.slicer-btn .chev { font-size: 0.7rem; opacity: 0.7; }
.slicer-badge {
  background: var(--brand-blue); color: #fff; border-radius: 999px;
  font-size: 0.7rem; min-width: 17px; height: 17px; display: inline-flex;
  align-items: center; justify-content: center; padding: 0 4px; font-weight: 700;
}

.slicer-panel {
  position: absolute; top: calc(100% + 6px); left: 0; z-index: 20;
  background: var(--surface-2);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-2);
  min-width: 230px; max-width: 320px;
  max-height: 280px;
  display: flex; flex-direction: column;
}
.slicer-panel-actions {
  display: flex; justify-content: space-between; gap: 8px;
  padding: 8px 10px; border-bottom: 1px solid var(--border);
}
.slicer-panel-actions button {
  font-family: inherit; font-size: 0.76rem; background: none; border: none;
  color: var(--brand-blue); cursor: pointer; padding: 2px 4px;
}
.slicer-options { overflow-y: auto; padding: 6px 4px; }
.slicer-option {
  display: flex; align-items: center; gap: 8px;
  padding: 6px 10px; border-radius: var(--radius-sm);
  font-size: 0.85rem; cursor: pointer;
}
.slicer-option:hover { background: var(--page-plane); }
.slicer-option input { accent-color: var(--brand-blue); }
.slicer-option .count { margin-left: auto; color: var(--text-muted); font-size: 0.76rem; }

.active-filters-summary {
  font-size: 0.82rem; color: var(--text-secondary);
  margin: -6px 0 20px;
}
.active-filters-summary:empty { display: none; }
.active-filters-summary b { color: var(--text-primary); }

/* ---------- KPI row ---------- */
.kpi-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-bottom: 28px;
}
.kpi-tile {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-1);
  padding: 20px 22px;
}
.kpi-label { font-size: 0.82rem; color: var(--text-secondary); margin: 0 0 8px; }
.kpi-value { font-size: 2rem; font-weight: 700; margin: 0; }
.kpi-sub { font-size: 0.8rem; color: var(--text-muted); margin: 6px 0 0; }
.kpi-tile.accent-good .kpi-value { color: var(--good); }
.kpi-tile.accent-critical .kpi-value { color: var(--critical); }
.kpi-tile.accent-blue .kpi-value { color: var(--brand-blue); }

/* ---------- Panels ---------- */
.panel {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-1);
  padding: 26px 28px;
  margin-bottom: 28px;
}
.panel-head h2 { margin: 0 0 4px; font-size: 1.2rem; }
.panel-head p { margin: 0 0 18px; }

.chart-wrap { position: relative; width: 100%; height: 320px; }
.chart-wrap-tall { height: 420px; }

.legend-list { display: flex; flex-wrap: wrap; gap: 8px 18px; margin: 14px 0 4px; }
.legend-item { font-size: 0.8rem; color: var(--text-secondary); }
.legend-item b { color: var(--text-primary); margin-right: 4px; }

/* ---------- Data tables ---------- */
.table-scroll { overflow-x: auto; margin-top: 18px; }
.data-table { width: 100%; border-collapse: collapse; font-size: 0.88rem; min-width: 480px; table-layout: auto; }

.individual-table { table-layout: fixed; }
.individual-table th, .individual-table td { white-space: normal; }
.individual-table th:first-child, .individual-table td:first-child { width: 140px; }
.individual-table th:not(:first-child):not(:last-child):not(:nth-last-child(2)),
.individual-table td:not(:first-child):not(:last-child):not(:nth-last-child(2)) {
  width: 90px; text-align: center; font-size: 0.72rem;
}
.individual-table td:not(:first-child):not(:last-child):not(:nth-last-child(2)) { font-size: 1rem; }
.individual-table th:last-child, .individual-table td:last-child,
.individual-table th:nth-last-child(2), .individual-table td:nth-last-child(2) { width: 90px; text-align: center; }
.data-table th, .data-table td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid var(--gridline);
  white-space: nowrap;
}
.data-table th {
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}
.data-table tbody tr:hover { background: var(--surface-1); }
.data-table td.wrap { white-space: normal; }
.data-table td.num, .data-table th.num { font-variant-numeric: tabular-nums; text-align: right; }

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 600;
}
.status-pill.good { background: var(--good-bg); color: var(--good); }
.status-pill.warning { background: var(--warning-bg); color: var(--warning); }
.status-pill.critical { background: var(--critical-bg); color: var(--critical); }

.ans-icon { font-weight: 700; }
.ans-icon.correct { color: var(--good); }
.ans-icon.incorrect { color: var(--critical); }

/* ---------- Question cards ---------- */
.question-cards { display: flex; flex-direction: column; gap: 20px; margin-top: 18px; }
.q-card {
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 22px;
  background: var(--surface-1);
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 24px;
}
.q-card-main { display: flex; flex-direction: column; gap: 14px; }
.q-card-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; }
.q-card-title { font-size: 1rem; font-weight: 600; margin: 0; flex: 1; }
.q-card-correct { font-size: 0.82rem; color: var(--text-secondary); margin: 0; }
.q-card-correct b { color: var(--good); }

.meter-row { display: flex; align-items: center; gap: 14px; }
.meter-value { font-size: 1.8rem; font-weight: 700; min-width: 70px; font-variant-numeric: tabular-nums; }
.meter-track {
  flex: 1;
  height: 12px;
  border-radius: 999px;
  background: var(--good-bg);
  overflow: hidden;
}
.meter-fill { height: 100%; border-radius: 999px; background: var(--good); transition: width .4s ease; }
.meter-track.tier-warning { background: var(--warning-bg); }
.meter-track.tier-warning .meter-fill { background: var(--warning); }
.meter-track.tier-critical { background: var(--critical-bg); }
.meter-track.tier-critical .meter-fill { background: var(--critical); }

.q-card-mini-table { width: 100%; border-collapse: collapse; font-size: 0.82rem; }
.q-card-mini-table th, .q-card-mini-table td { padding: 6px 8px; border-bottom: 1px solid var(--gridline); }
.q-card-mini-table th { color: var(--text-muted); font-weight: 600; text-transform: uppercase; font-size: 0.7rem; }
.q-card-mini-table td.num { text-align: right; font-variant-numeric: tabular-nums; }

.q-card-chart { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 10px; }
.q-card-chart .chart-wrap { height: 200px; }

@media (max-width: 720px) {
  .q-card { grid-template-columns: 1fr; }
}

/* ---------- Footer ---------- */
.page-footer { text-align: center; padding: 24px; color: var(--text-muted); font-size: 0.8rem; }

/* ---------- Print ---------- */
@media print {
  body { background: #fff; }
  .no-print { display: none !important; }
  .panel, .q-card, .kpi-tile { box-shadow: none; break-inside: avoid; }
  .topbar { box-shadow: none; }
}