:root {
  --bg: #0f172a;
  --panel: #111827;
  --card: #ffffff;
  --muted: #64748b;
  --line: #e5e7eb;
  --accent: #2563eb;
  --danger: #dc2626;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: #f1f5f9;
  color: #0f172a;
}
.topbar {
  background: linear-gradient(135deg, #0f172a, #1e293b);
  color: #fff;
  padding: 18px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.topbar h1 { margin: 0 0 4px; font-size: 24px; }
.topbar p { margin: 0; opacity: 0.85; }
.pill {
  background: rgba(255,255,255,0.12);
  border: 1px solid rgba(255,255,255,0.15);
  padding: 8px 12px;
  border-radius: 999px;
}
.app-shell {
  display: grid;
  grid-template-columns: 360px 1fr;
  min-height: calc(100vh - 88px);
}
.sidebar {
  border-right: 1px solid #dbe2ea;
  background: #f8fafc;
  padding: 18px;
  overflow-y: auto;
}
.workspace { padding: 18px; }
.card {
  background: #fff;
  border: 1px solid #e2e8f0;
  border-radius: 16px;
  padding: 16px;
  margin-bottom: 16px;
  box-shadow: 0 8px 24px rgba(15,23,42,0.05);
}
.card h2 {
  margin: 0 0 12px;
  font-size: 17px;
}
.tool-group { margin-bottom: 12px; }
.tool-group label {
  display: block;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 6px;
}
.inline-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}
input[type="text"], input[type="number"], input[type="file"], select, button, a.download-link {
  width: 100%;
  border-radius: 10px;
  border: 1px solid #cbd5e1;
  padding: 10px 12px;
  font-size: 14px;
}
button {
  cursor: pointer;
  background: #fff;
}
button:hover { border-color: #94a3b8; }
button.primary {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}
.tool-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}
.status {
  margin-top: 10px;
  font-size: 13px;
  color: var(--muted);
  min-height: 18px;
}
.workspace-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
  gap: 10px;
}
.viewer-shell {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 16px;
  height: calc(100vh - 160px);
}
.thumbs-panel,
.canvas-panel {
  background: #fff;
  border: 1px solid #e2e8f0;
  border-radius: 16px;
  padding: 14px;
  box-shadow: 0 8px 24px rgba(15,23,42,0.05);
}
.thumbs-panel { overflow-y: auto; }
#thumbs { display: flex; flex-direction: column; gap: 10px; }
.thumb {
  border: 2px solid transparent;
  border-radius: 12px;
  padding: 8px;
  background: #f8fafc;
  cursor: pointer;
}
.thumb.active { border-color: var(--accent); }
.thumb canvas { width: 100%; display: block; border-radius: 6px; }
.thumb .thumb-label { font-size: 12px; margin-top: 6px; text-align: center; }
.canvas-panel { overflow: auto; }
.canvas-wrap {
  position: relative;
  width: fit-content;
  margin: 0 auto;
}
#pdfCanvas, #overlayCanvas {
  display: block;
  max-width: 100%;
}
#overlayCanvas {
  position: absolute;
  left: 0;
  top: 0;
  z-index: 5;
}
.download-link {
  display: none;
  text-decoration: none;
  text-align: center;
  margin-top: 10px;
  background: #ecfeff;
  color: #155e75;
}
.pager {
  display: flex;
  align-items: center;
  gap: 10px;
}
@media (max-width: 1100px) {
  .app-shell, .viewer-shell { grid-template-columns: 1fr; }
  .viewer-shell { height: auto; }
}