:root {
  --paper: #f7f4ec;
  --ink: #1c1c1c;
  --accent: #1e66d6;
  --accent-soft: #e3edfb;
  --line: #c9c2b2;
  --panel: #fffdf8;
  --danger: #c0392b;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-user-select: none;
  user-select: none;
  -webkit-touch-callout: none;
  -webkit-tap-highlight-color: transparent;
}

#toolbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--panel);
  border-bottom: 1px solid var(--line);
  padding: 8px 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
}
.brand .logo { font-size: 22px; color: var(--accent); }
.brand h1 { font-size: 16px; margin: 0; font-weight: 650; letter-spacing: 0.2px; }
.brand .version {
  font-size: 11px;
  font-weight: 600;
  color: #6b6555;
  background: #f0ede4;
  border-radius: 8px;
  padding: 2px 8px;
  margin-left: 2px;
}

.tb-row {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  align-items: center;
  margin-bottom: 6px;
}
.tb-row:last-child { margin-bottom: 0; }

.tb-group {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  align-items: center;
  background: #f0ede4;
  border-radius: 10px;
  padding: 13px 4px 4px;
}
.tb-group::before {
  content: attr(data-label);
  position: absolute;
  top: 3px;
  left: 8px;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.4px;
  text-transform: uppercase;
  color: #8b8573;
  pointer-events: none;
}

.tb-group button, .tb-group select {
  appearance: none;
  border: 1px solid transparent;
  background: transparent;
  border-radius: 8px;
  padding: 8px 10px;
  font-size: 14px;
  color: var(--ink);
  cursor: pointer;
  min-height: 40px;
  white-space: nowrap;
}
.tb-group select {
  border: 1px solid var(--line);
  background: #fff;
  padding-right: 24px;
}
.tb-group button:hover { background: #e6e2d6; }
.tb-group button.active {
  background: var(--accent);
  color: #fff;
  font-weight: 600;
}
.tb-group button.danger { color: var(--danger); }
.tb-group button.danger:hover { background: #f5deda; }

#hint {
  margin: 10px 12px 4px;
  font-size: 13px;
  color: #5a5546;
  background: var(--accent-soft);
  border: 1px solid #c9dbf5;
  border-radius: 10px;
  padding: 8px 12px;
}

main { padding: 8px 12px 40px; }

#systems { display: flex; flex-direction: column; gap: 14px; }

.system {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 10px 10px 6px;
  box-shadow: 0 1px 4px rgba(0,0,0,0.05);
}
.system-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 4px;
  padding: 0 4px;
}
.system-header .sys-name { font-size: 13px; color: #6b6555; font-weight: 600; }
.system-header button {
  appearance: none;
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 8px;
  padding: 6px 10px;
  font-size: 13px;
  cursor: pointer;
}
.system-header button:hover { background: #f0ede4; }
.system-header .spacer { flex: 1; }
.system-header .delete { color: var(--danger); border-color: #eccfc9; }

.system canvas {
  display: block;
  width: 100%;
  border-radius: 8px;
  background: #fff;
  touch-action: none;
  -webkit-user-select: none;
  user-select: none;
  cursor: crosshair;
}

.canvas-wrap { position: relative; }

.eraser-cursor {
  position: absolute;
  left: 0;
  top: 0;
  transform: translate(-50%, -50%);
  border: 2px solid rgba(214, 51, 51, 0.85);
  border-radius: 50%;
  background: rgba(214, 51, 51, 0.12);
  pointer-events: none;
  display: none;
  z-index: 5;
}

.add-system-row { margin: 12px 0; text-align: center; }
#btn-add-system {
  appearance: none;
  border: 1px dashed var(--line);
  background: transparent;
  color: #6b6555;
  border-radius: 12px;
  padding: 12px 22px;
  font-size: 15px;
  cursor: pointer;
}
#btn-add-system:hover { background: #efece2; }

footer {
  padding: 10px 16px 28px;
  font-size: 12px;
  color: #8b8573;
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: center;
}

@media (max-width: 640px) {
  .tb-group button, .tb-group select { padding: 7px 8px; font-size: 13px; min-height: 38px; }
  .brand h1 { font-size: 15px; }
}

/* ---------- Print / PDF (DIN A4) ---------- */
@media print {
  #toolbar, #hint, .add-system-row, footer, .system-header, .eraser-cursor, #file-import {
    display: none !important;
  }
  body { background: #fff; }
  main { padding: 0; }
  #systems { gap: 0; }
  .system {
    border: none;
    box-shadow: none;
    border-radius: 0;
    padding: 4px 0;
    break-inside: avoid;
    page-break-inside: avoid;
  }
  @page { size: A4; margin: 12mm; }
}