:root {
  --bg: #f5f6f8;
  --panel: #ffffff;
  --line: #e5e7eb;
  --text: #111827;
  --muted: #6b7280;
  --soft: #f8fafc;
  --danger: #b91c1c;
  --shadow: 0 8px 24px rgba(15, 23, 42, 0.06);
  --radius: 16px;
  --page-shadow: 0 18px 40px rgba(15, 23, 42, 0.12);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  min-height: 100%;
  font-family: Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
}

button, input, select, textarea { font: inherit; }
button { cursor: pointer; }

.app-shell {
  min-height: 100vh;
  display: grid;
  grid-template-rows: auto 1fr;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  padding: 16px 22px;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
  position: sticky;
  top: 0;
  z-index: 20;
}

.brand-wrap {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-mark {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: #111827;
  color: white;
  font-weight: 700;
}

.brand-wrap h1,
.preview-header h2,
.section-head h2 {
  margin: 0;
  font-size: 1.05rem;
}

.brand-wrap p,
.preview-header p,
.muted {
  margin: 2px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.small-note { font-size: 0.82rem; }

.topbar-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.workspace {
  display: grid;
  grid-template-columns: minmax(370px, 450px) minmax(0, 1fr);
  gap: 18px;
  padding: 18px;
  min-height: 0;
}

.left-panel,
.right-panel { min-height: 0; }

.left-panel {
  display: grid;
  grid-template-rows: auto auto 1fr;
  gap: 16px;
}

.right-panel {
  display: grid;
  grid-template-rows: auto 1fr;
  gap: 14px;
}

.panel-block,
.preview-header {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.toolbar-panel,
.tabs-panel,
.properties-panel,
.preview-header { padding: 16px; }

.toolbar-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.toolbar-row + .toolbar-row { margin-top: 14px; }
.top-actions-row { justify-content: space-between; }

.formats-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.formats-row label,
.properties-content label {
  display: grid;
  gap: 6px;
  font-size: 0.92rem;
}

select,
textarea,
input[type="text"],
input[type="number"] {
  width: 100%;
  border: 1px solid #d1d5db;
  border-radius: 12px;
  background: white;
  padding: 10px 12px;
  color: var(--text);
}

textarea { resize: vertical; }

.btn {
  border: 1px solid #111827;
  background: #111827;
  color: white;
  padding: 10px 14px;
  border-radius: 12px;
  transition: 0.18s ease;
}

.btn:hover { transform: translateY(-1px); }
.btn.ghost { background: white; color: #111827; border-color: #d1d5db; }
.btn.primary { background: #111827; }
.btn.danger { color: var(--danger); }

.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
}

.file-btn { position: relative; overflow: hidden; }
.file-btn input {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
}

.dropdown-wrap { position: relative; }

.dropdown-menu {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  width: 260px;
  max-height: 70vh;
  overflow: auto;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: white;
  box-shadow: var(--shadow);
  z-index: 10;
}

.menu-group + .menu-group {
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
}

.menu-title {
  font-size: 0.8rem;
  color: var(--muted);
  margin: 0 0 6px;
  padding: 0 6px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.dropdown-menu button {
  display: block;
  width: 100%;
  text-align: left;
  border: 0;
  background: transparent;
  padding: 10px 12px;
  border-radius: 10px;
}

.dropdown-menu button:hover { background: var(--soft); }
.hidden { display: none !important; }

.tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 14px;
}

.tab-btn {
  border: 1px solid var(--line);
  background: white;
  color: var(--muted);
  padding: 9px 12px;
  border-radius: 12px;
}

.tab-btn.active {
  color: var(--text);
  border-color: #cbd5e1;
  background: #f8fafc;
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

.code-tab textarea {
  min-height: 290px;
  font-family: Consolas, Monaco, monospace;
  font-size: 13px;
  line-height: 1.55;
}

.code-actions {
  display: flex;
  justify-content: flex-end;
  margin-top: 10px;
}
.code-actions.between {
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}

.blocks-list {
  display: grid;
  gap: 10px;
  max-height: 340px;
  overflow: auto;
}

.block-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 12px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: white;
}

.block-card.selected {
  border-color: #94a3b8;
  background: #fafcff;
}

.block-card-main { min-width: 0; }
.block-card-type { display: block; margin-bottom: 3px; }
.block-card-summary {
  margin: 0;
  color: var(--muted);
  font-size: 0.88rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.block-card-actions {
  display: flex;
  gap: 6px;
}

.block-card-actions button {
  width: 30px;
  height: 30px;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: white;
}

.section-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 12px;
}

.properties-content {
  display: grid;
  gap: 12px;
}

.properties-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.inline-check {
  display: flex !important;
  align-items: center;
  gap: 8px;
}
.inline-check input { width: auto; }
.empty-state {
  color: var(--muted);
  padding: 18px;
  border: 1px dashed var(--line);
  border-radius: 12px;
  background: #fbfbfc;
}

.preview-stage {
  min-height: 0;
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #eef1f5;
  padding: 20px;
}

.page-preview {
  margin: 0 auto;
  background: white;
  box-shadow: var(--page-shadow);
  transition: 0.15s ease;
}

.page-content {
  padding: 56px;
  min-height: 100%;
}

.page-preview.a4.portrait { width: 906px; min-height: 1235px; }
.page-preview.a4.landscape { width: 1235px; min-height: 906px; }
.page-preview.a5.portrait { width: 671px; min-height: 906px; }
.page-preview.a5.landscape { width: 906px; min-height: 671px; }
.page-preview.a3.portrait { width: 1235px; min-height: 1699px; }
.page-preview.a3.landscape { width: 1699px; min-height: 1235px; }



.preview-block {
  cursor: pointer;
  outline: 1px solid transparent;
  border-radius: 8px;
  transition: 0.12s ease;
}

.preview-block:hover { outline-color: #dbe4ef; }
.preview-selected {
  outline-color: #93c5fd !important;
  background: rgba(239, 246, 255, 0.55);
}

.preview-page-title,
.preview-subtitle,
.preview-paragraph,
.preview-instruction,
.preview-truefalse,
.preview-shortanswer,
.preview-fillblank,
.preview-mc {
  line-height: 1.5;
}

.preview-page-title { font-weight: 700; }
.preview-subtitle { color: #374151; font-weight: 600; }
.preview-instruction-number {
  font-weight: 700;
  margin-right: 8px;
}

.preview-tf-item,
.preview-mc-item,
.preview-fillblank-item {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 8px;
}

.preview-mc-options {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 14px;
  margin-top: 8px;
}

.preview-badges,
.preview-option-badges {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 6px;
  flex-shrink: 0;
}

.preview-badge {
  min-width: 26px;
  padding: 4px 8px;
  border: 1px solid #cbd5e1;
  border-radius: 999px;
  text-align: center;
  font-size: 0.86em;
}

.preview-shortanswer-line {
  border-bottom: 1px solid #9ca3af;
  height: 18px;
  margin-top: 8px;
}

.preview-fillblank-gap {
  display: inline-block;
  min-width: 120px;
  border-bottom: 1px solid #111827;
  transform: translateY(-2px);
}

.preview-image figure {
  margin: 0;
}

.preview-image img {
  display: block;
  max-width: 100%;
  height: auto;
}

.preview-image figcaption {
  margin-top: 6px;
  color: var(--muted);
  font-size: 0.9em;
}

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

.preview-table th,
.preview-table td {
  border: 1px solid #cbd5e1;
  padding: 10px;
}

.preview-math-source {
  margin-top: 8px;
  color: var(--muted);
  font-family: Consolas, Monaco, monospace;
  font-size: 0.85em;
}

@media (max-width: 1180px) {
  .workspace {
    grid-template-columns: 1fr;
  }

  .preview-stage { padding: 10px; }
  .page-preview.a4.portrait,
  .page-preview.a5.portrait,
  .page-preview.a3.portrait,
  .page-preview.a4.landscape,
  .page-preview.a5.landscape,
  .page-preview.a3.landscape {
    width: 100%;
    min-height: auto;
  }
}

@media print {
  .topbar,
  .left-panel,
  .preview-header {
    display: none !important;
  }

  .workspace {
    display: block;
    padding: 0;
  }

  .right-panel { display: block; }
  .preview-stage {
    padding: 0;
    border: 0;
    background: white;
    overflow: visible;
  }

  .page-preview {
    width: auto !important;
    min-height: auto !important;
    box-shadow: none;
  }

  .page-content { padding: 0; }


  
  .preview-selected {
    outline: none !important;
    background: none !important;
  
}

}


.preview-exercise-points {
  text-align: right;
  margin-top: 8px;
  font-size: 0.95em;
}

.preview-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.preview-header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.page-nav {
  display: flex;
  align-items: center;
  gap: 8px;
}

#pageIndicator {
  min-width: 90px;
  text-align: center;
}

.preview-header-row {
  display: flex;
  gap: 20px;
  align-items: flex-end;
  flex-wrap: wrap;
}

.preview-header-field {
  display: flex;
  flex-direction: column;
}

.preview-header-label {
  font-size: 0.9em;
  margin-bottom: 4px;
}

.preview-header-line {
  min-height: 16px;
  border-bottom: 1px solid #111827;
}


.preview-page-title {
  font-size: 24px;
}

.preview-subtitle {
  font-size: 22px;
}

.preview-paragraph,
.preview-instruction,
.preview-truefalse,
.preview-shortanswer,
.preview-fillblank,
.preview-mc {
  font-size: 16px;
}

.preview-fillblank-gap {
  display: inline-block;
  width: 120px;
  border-bottom: 1px solid #111827;
  margin: 0 4px;
}

.preview-header-row {
  width: 100%;
}